二、填空题（本大题共10小题，每小题1分，共10分） §0
1. ★Photovoltaics (often abbreviated as PV ) is a simple and elegant method of harnessing the sun's energy. 2. ★PV devices (solar cells) are unique in that they directly convert the incident solar radiation into electricity , with no noise, pollution or moving parts, making them robust, reliable and long lasting.
3. ★Photovoltaics is the process of converting sunlight directly into electricity using solar cells . 4. ★The first photovoltaic device was demonstrated in 1839 by Edmond Becquerel, as a young 19 year old working in his father‘s laboratory in France.
5. ★The first practical photovoltaic device was demonstrated in the 1950s. 6. ★★Research and development of photovoltaics received its first major boost from the space industry in the 1960s. §1
1. ★A photon is characterized by either a wavelength, denoted by , or equivalently an energy, denoted by E. 2. ★★There is an inverse relationship between the energy of a photon (E) and the wavelength of the light ()
given by the equation: ，.
3. ★★The photon flux is defined as the number of photons per second per unit area. 4. ★★★The total power density emitted from a light source can be calculated by integrating the spectral irradiance over all wavelengths or energies of interest. 5. ★★In the analysis of solar cells, the photon flux is often needed as well as the spectral irradiance. 6. ★The blackbody sources which are of interest to photovoltaics, emit light in the visible region. 7. ★★★The spectral irradiance from a blackbody is given by Plank's radiation law. 8. ★★The peak wavelength of the spectral irradiance is determined by differentiating the spectral irradiance and solving the derivative when it equals 0. The result is known as Wien‗s Law:pm
2900 T.R29. ★★★Solar radiation in space: H02Hsun Hsun=5.961×107W/m2.
D.
10. ★The solar radiation outside the earth's atmosphere have been defined as a standard value called air mass zero (AM0) and takes a value of 1.353 kW/m2.
11. ★The spectral irradiance from a blackbody at 6000 K (at the same apparent diameter as the sun when viewed
from earth); from the sun‘s photosphere as observed just outside earth‘s atmosphere (AM0); and from the sun‘s photosphere after having passed through 1.5 times the thickness of earth‘s atmosphere (AM1.5G). 2s where is the angle from the vertical (zenith 12. ★★The Air Mass is defined as:AM1AM1cosh. ,1
angle).
13. ★★When the sun is directly overhead, the Air Mass is 1. 14. ★The standard spectrum at the Earth's surface is called AM1.5G (the G stands for global and includes both
direct and diffuse radiation) or AM1.5D (which includes direct radiation only), these calculations give approximately 970 W/m2 for AM1.5G。
15. ★The standard AM1.5G spectrum has been normalized to give 1 kW/m2 due to the convenience of the round
number and the fact that there are inherently variations in incident solar radiation.
16. ★The standard spectrum outside the Earth's atmosphere is called AM0, because at no stage does the light
pass through the atmosphere.
17. ★The standard AM0 spectrum is typically used to predict the expected performance of cells in space. 18. ★★★Wavelengths below 0.3 m are strongly absorbed by ozone. The absorption bands around 1 m are
produced by water vapor absorption, complemented by CO2 absorption at longer wavelengths.
19. ★★★The air mass represents the proportion of atmosphere that the light must pass through before striking
the Earth relative to its overhead pathlength.
20. ★★Diffuse radiation is predominantly at the blue end of the spectrum because of more effective scattering at small wavelengths. Hence, the sky appears blue.
21. ★★AM1 radiation (radiation when the sun is directly overhead), has a diffuse component of about 10%
when skies are clear.
22. ★★★Carbon dioxide absorbs strongly in the 13-19 m wavelength band and water vapour, another
atmospheric gas, absorbs strongly in the 4-7 m wavelength band. Most outgoing radiation (70%) escapes in the ―window‖ between 7-13 m.
23. ★★The two common methods which characterize solar radiation are the solar radiance (or radiation) and
solar insolation. 24. ★★While solar irradiance is most commonly measured, a more common form of radiation data used in
system design is the solar insolation. 25. ★The solar radiance is an instantaneous power density in units of kW/m2. 26. ★★The solar insolation is the total amount of solar energy received at a particular location during a specified time period, often in units of kWh/(m2 day), also in units of MJ/m2 per year. 27. ★★The average daily solar insolation in units of kWh/m2 per day is sometimes referred to as ―peak sun hours‖. For example, a location that receives 8 kWh/m2 per day can be said to have received 8 hours of sun per day at 1 kW/m2.
28. ★The declination of the sun is the angle between the equator and a line drawn from the centre of the earth to 360 the centre of the sun. δ23.45sin365284d29. ★★★The declination of the sun is zero at the equinoxes (March 22 and September 22), positive during the northern hemisphere summer and negative during the northern hemisphere winter. 30. ★★★The elevation or altitude angle is the angular height of the sun in the sky measured from the horizontal.
The elevation is 0° at sunrise and 90° when the sun is directly overhead. 31. ★★The zenith angle is similar to the elevation angle but it is measured from the vertical rather than from the horizontal.
32. ★★★The azimuth angle is the compass direction from which the sunlight is coming with North = 0°, South
= 180°, 90° at sunrise and 270° at sunset.
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33. ★★For a fixed tilt angle, the maximum power over the course of a year is obtained when the tilt angle is
equal to the latitude of the location. 34. ★The module is orientated to the equator so it faces north in the southern hemisphere and south in the
northern hemisphere.
35. ★★The sun is at an altitude of 30° to the horizontal, the corresponding air mass is 2 . 36. ★★The length of the shadow cast by a vertical post with a height of 1 m under AM1.5 illumination
is . §2
1. ★★The most important parameters of a semiconductor material for solar cell operation are: (1) the band gap; (2）the number of free carriers available for conduction; (3）the generation and recombination of free carriers in response to light shining on the material.
2. ★The electrical properties of semiconductors can be explained using two models, the bond and the band models.
3. ★★The band model describes semiconductor behavior in terms of the energy level between valence and conduction bands. 4. ★★The lower energy level of a semiconductor is called the \"valence band\" (EV) and the energy level at which an electron can be considered free is called the \"conduction band\" (EC). The band gap (EG) is the distance between the conduction band and valence band.
5. ★The band gap corresponds to the minimum energy needed to release an electron from a valence bond to the conduction band where it can conduct a current.
6. ★★★Both the electron and hole can participate in conduction and are called \"carriers\". 7. ★★It is possible to shift the balance of electrons and holes in a silicon crystal lattice by \"doping\" it with other atoms.
8. ★★Atoms with one more valence electron than silicon are used to produce \"n-type\" semiconductor material, which adds electrons to the conduction band and hence increases the number of electrons.
9. ★★★In p-type material, the number of electrons trapped in bonds is higher, thus effectively increasing the number of holes.
10. ★★In doped material, there is always more of one type of carrier than the other and the type of carrier with
the higher concentration is called a \"majority carrier\while the lower concentration carrier is called a \"minority carrier\". 11. ★★★The number of carriers in the conduction and valence band with no externally applied bias is called the
intrinsic carrier concentration. 12. ★★★For majority carriers, the equilibrium carrier concentration is equal to the intrinsic carrier concentration
plus the number of free carriers added by doping the semiconductor. 13. ★★Silicon or other semiconductor materials used for solar cells can be single crystalline, multicrystalline,
polycrystalline or amorphous. 14. ★★Terminology for various types of crystalline silicon (c-Si)
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Descriptor Single crystal Multicrystalline Polycrystalline Microcrystalline Symbol sc-Si mc-Si pc-Si c-Si Grain Size >10cm 1mm-10cm 1m-1mm <1m Common Growth Techniques Czochralski (CZ) float zone (FZ) Cast, sheet, ribbon Chemical-vapor deposition Plasma deposition 15. ★★★It has been found that the incorporation of atomic hydrogen in amorphous silicon, to a level of 5–10%, saturates the dangling bonds and improves the quality of the material.
16. ★★The minority carrier diffusion lengths in the silicon-hydrogen alloys (a-Si:H) are much less than 1 m. 17. ★★Photons incident on the surface of a semiconductor will be either reflected from the top surface, will be absorbed in the material or, failing either of the above two processes, will be transmitted through the material. 18. ★For photovoltaic devices, reflection and transmission are typically considered loss mechanisms as photons which are not absorbed do not generate power.
19. ★★★If the photon is absorbed it will raise an electron from the valence band to the conduction band. 20. ★The absorption depth is a useful parameter which gives the distance into the material at which the light drops
to about 36% of its original intensity, or alternately has dropped by a factor of 1/e. 21. ★★Neglecting reflection, the amount of light which is absorbed by a material depends on the absorption coefficient and the thickness of the absorbing material. 22. ★★★Assuming that the loss in light intensity (i.e., the absorption of photons) directly causes the generation
of an electron-hole pair, and then the generation G in a thin slice of material is determined by finding the change in light intensity across this slice. 23. ★★★There are three basic types of recombination in the bulk of a single-crystal semiconductor. These are
Radiative recombination, Auger recombination and Shockley-Read-Hall(SRH) recombination. 24. ★★Auger recombination is most important in heavily doped or heavily excited material. 25. ★★The \"minority carrier lifetime\" of a material, is defined the average time for recombination to occur
electron-hole generation. A related parameter, the \"minority carrier diffusion length\" is the average distance a carrier can move from point of generation until it recombines.
26. ★For many types of silicon solar cell, SRH recombination is the dominant recombination mechanism. 27. ★★In silicon, the lifetime can be as high as 1 s. For a single crystalline silicon solar cell, the diffusion length
is typically 100-300 m.
28. ★★The surface recombination rate is limited by the rate at which minority carriers move towards the surface. 29. ★★The reduction of the number of dangling bonds, and hence the recombination, is achieved by growing a
layer on top of the semiconductor surface which ties up some of these dangling bonds. This reduction of dangling bonds is known as surface passivation. 30. ★★★Electrons in the conduction band and holes in the valence band are considered \"free\" carriers in the
sense that they can move throughout the semiconductor crystal.
31. ★★Although carriers in a semiconductor are in constant random motion, there is no net motion of carriers
unless there is a concentration gradient or an electric field. 32. ★★A p-n junction aggregates the recombination, generation, diffusion and drift effects described in the
previous pages into a single device.
33. ★★★The current caused by the diffusion of carriers across the junction is called the diffusion current. 34. ★★★Minority carriers which reach the edge of the diffusion region are swept across it by the electric field in
the depletion region. This current is called the drift current 35. ★★★In equilibrium, the net current from the device is zero. 36. ★★★Semiconductor devices have three modes of operation: (1)thermal Equilibrium, (2)Steady State, (3)Transient. 4
37. ★★By applying a positive voltage to the p-type material and a negative voltage to the n-type material, an
electric field with opposite direction to that in the depletion region is applied across the device. §3
1. ★A solar cell is an electronic device which directly converts sunlight into electricity. 2. ★★Light shining on the solar cell produces both a current and a voltage to generate electric power. This process requires firstly, a material in which the absorption of light raises an electron to a higher energy state, and secondly, the movement of this higher energy electron from the solar cell into an external circuit. 3. ★★The basic steps in the operation of a solar cell are: (1)the generation of light-generated carriers; (2)the collection of the light-generated carries to generate a current; (3)the generation of a large voltage across the solar cell; (4)the dissipation of power in the load and in parasitic resistances.
4. ★★Electron-hole pairs will be generated in the solar cell provided that the incident photon has an energy greater than that of the band gap. 5. ★★The collection probability in conjunction with the generation rate in the solar cell determine the light-generated current from the solar cell.
6. ★★The \"quantum efficiency\" (QE) is the ratio of the number of carriers collected by the solar cell to the number of photons of a given energy incident on the solar cell.
7. ★★Maximum use can only be made of incoming sunlight if the bandgap is in the range 1.0–1.6 eV. 8. ★★The bandgap of silicon, at 1.1 eV, is close to optimum, while that of gallium arsenide, at 1.4 eV, is even better, in principle.
9. ★★★This strong wavelength dependence of response makes cell performance in turn strongly dependent on the spectral content of sunlight. 10. ★★Voltage is generated in a solar cell by a process known as the \"photovoltaic effect\". 11. ★★★The collection of light-generated carriers by the p-n junction causes a movement of electrons to the n-type side and holes to the p-type side of the junction.
12. ★★★The current from the solar cell is the difference between light-generated current and the forward bias current.
13. ★★The short-circuit current is the maximum current through the solar cell when the voltage across the solar cell is zero. 14. ★★When comparing solar cells of the same material type, the most critical material parameter is the diffusion length and surface passivation. 15. ★★The open-circuit voltage is the maximum voltage available from a solar cell, and occurs when the current through the device is zero.
16. ★★The fill factor (FF) is defined as the ratio of the maximum power from the solar cell to the product of the short-circuit current (Isc) and the open-circuit voltage (Voc). 17. ★★Efficiency is defined as the ratio of energy output from the solar cell to input energy from the sun. 18. ★★★The characteristic resistance of a solar cell is the output resistance of the solar cell at its maximum
power point. If the resistance of the load is equal to the characteristic resistance of the solar cell, then the maximum power is transferred to the load and the solar cell operates at its maximum power point. 19. ★The most common parasitic resistances in solar cells are series resistance and shunt resistance. 20. ★In most cases and for typical values of shunt and series resistance, the key impact of parasitic resistance is to
reduce the fill factor. 21. ★★★Series resistance in a solar cell has three causes: firstly, the movement of current through the emitter and
base of the solar cell; secondly, the contact resistance between the metal contact and the silicon; finally, the 5
resistance of the top and rear metal contacts.
22. ★The main impact of series resistance is to reduce the fill factor, although excessively high values may also reduce the short-circuit current. 23. ★Series resistance does not affect the open-circuit voltage of the solar cell since the overall current flow
through the solar cell, and therefore through the series resistance is zero.
24. ★A straight-forward method of estimating the series resistance from a solar cell is to find the slope of the IV
curve at the open-circuit voltage point.
25. ★An estimate for the value of the shunt resistance of a solar cell can be determined from the slope of the IV
curve near the short-circuit current point. 26. ★★★Increases in temperature reduce the band gap of a semiconductor, thereby effecting most of the
semiconductor material parameters.
27. ★In a solar cell, the parameter most affected by an increase in temperature is the open-circuit voltage. 28. ★★A concentrator cell is a solar cell designed to operate under illumination greater than 1 sun. 29. ★★★The most common and basic measurement technique for determining solar cell performance is the
measurement of the IV curve under lighted conditions, using a carefully controlled light source and controlling the temperature of the solar cell. 30. ★★Four point probes are used to eliminate the effect of series resistance in the test leads and contact
resistance between the probes and the cell.
31. ★Terrestrial solar cells are measured under AM1.5 conditions and at a temperature of 25°C. §4
1. ★★★For silicon solar cells, a more realistic efficiency under one sun operation is about 26 to 28%. The maximum efficiency measured for a silicon solar cell is currently 24.7% under AM1.5G. 2. ★Optical losses chiefly affect the power from a solar cell by lowering the short-circuit current. 3. ★★★The thickness of the anti-reflection coating is chosen so that the wavelength in the dielectric material is one quarter the wavelength of the incoming wave. 4. ★★For photovoltaic applications, the refractive index, and thickness are chosen in order to minimize reflection for a wavelength of 0.6 m.
5. ★★★Surface texturing, either in combination with an anti-reflection coating or by itself, can also be used to minimize reflection. 6. ★★★This type of texturing is called ―random pyramid‖ texture, and is commonly used in industry for single
crystalline wafers.
7. ★★★ Surface texturing used is known as \"inverted pyramid\" texturing. Using this texturing
scheme, the pyramids are etched down into the silicon surface rather than etched pointing upwards from the surface.
8. ★★★Using total internal reflection, light can be trapped inside the cell and make multiple passes through the cell, thus allowing even a thin solar cell to maintain a high optical path length.
9. ★★The metallic top contacts are necessary to collect the current generated by a solar cell. while \"fingers\" are finer areas of metalization which collect current for delivery to the busbars，which are connected directly to the external leads.
10. ★★Contact resistance losses occur at the interface between the silicon solar cell and the metal contact. To
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keep top contact losses low, the top N layer must be as heavily doped as possible. 11. ★★★If a high level of phosphorus is diffused into silicon, the excess phosphorus lies at the surface of the cell,
creating a \"dead layer\12. ★★An optimum silicon solar cell with light trapping and very good surface passivation is about 100 μm thick. However, thickness between 200 and 500 μm are typically used.
13. ★While the low absorption coefficient for silicon can be overcome by light trapping. §5
1. ★★★A PV module consists of individual solar cells electrically connected together to increase their power output. 2. ★★★A PV module consists of a number of interconnected solar cells (typically 36/60 connected in series) encapsulated into a single, long-lasting, stable unit.
3. ★Amorphous silicon solar cells are often encapsulated into a flexible array, while bulk silicon solar cells for remote power applications are usually rigid with glass front surfaces. 4. ★Module lifetimes and warranties on bulk silicon PV modules are often about 20 years, indicating the robustness of an encapsulated PV module.
5. ★★Most bulk silicon PV modules consist of a transparent top surface, an encapsulant, a rear layer and a frame around the outer edge.
6. ★★★In most bulk silicon PV modules, the top surface is glass, the encapsulant is EVA (ethyl vinyl acetate) and the rear layer is Tedlar. 7. ★★★There are several choices for a top surface material including acrylic, polymers and glass. Tempered, low iron-content glass is most commonly used as it is low cost, strong, stable, highly transparent, impervious to water and gases and has good self-cleaning properties.
8. ★★★In bifacial modules both the front and the rear must be optically transparent. 9. ★★The packing density of solar cells in a PV module refers to the area of the module that is covered with solar cells compared to that which is blank.
10. ★★A bulk silicon PV module consists of multiple individual solar cells connected, nearly always in series, to increase the power and voltage above that from a single solar cell.
11. ★★The voltage of a PV module is usually chosen to be compatible with a 12V battery. 12. ★Mismatch losses are caused by the interconnection of solar cells or modules which do not have identical
properties or which experience different conditions from one another.
13. ★Mismatch losses are a serious problem in PV modules and arrays under some conditions because the output
of the entire PV module is determined by the solar cell with the lowest output. 14. ★★Although mismatch may occur in any of the cell parameters, large mismatches are most commonly caused
by differences in either the short-circuit current or open-circuit voltage. 15. ★Of the two simplest types of mismatch considered (mismatch in short-circuit current or in open-circuit
voltage), a mismatch in the short-circuit current is more common, as it can easily be caused by shading part of the module.
16. ★★Hot-spot heating occurs when a large number of series connected cells cause a large reverse bias across the shaded cell, leading to large dissipation of power in the poor cell.
17. ★The destructive effects of hot-spot heating may be circumvented through the use of a by-pass diode. 18. ★★Under normal operation, each solar cell will be forward biased and therefore the bypass diode will be
reverse biased and will effectively be an open circuit. 19. ★In addition to the use of by-pass diodes to prevent mismatch losses, an additional diode, called a blocking diode, may be used to minimize mismatch losses.
20. ★★★An unwanted side-effect of the encapsulation of solar cells into a PV module is that the encapsulation
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alters the heat flow into and out of the PV module, thereby increasing the operating temperature of the PV module.
21. ★★A PV module exposed to sunlight generates heat as well as electricity. 22. ★★★Light which has an energy below that of the band gap of the solar cells cannot contribute to electrical power, but if it is absorbed by the solar cells or by the module, this light will contribute to heating. 23. ★★The ability of the PV module to transfer heat to its surroundings is characterized by the thermal resistance and configuration of the materials used to encapsulate the solar cells. 24. ★A PV module will be typically rated at 25°C under 1 kW/m2.
25. ★★The Nominal Operating Cell Temperature (NOCT) is defined as the temperature reached by open circuited cells in a module under the conditions as listed below: (1) Irradiance on cell surface = 800 W/m2; (2) Air Temperature = 20°C; (3) Wind Velocity = 1 m/s; Mounting = open back side.
26. ★★If glass is used for the top surface, it must be tempered, since the central areas of the module become
hotter than areas near the frame.
27. ★★★Nevertheless, there are several failure modes and degradation mechanisms which may reduce the power
output or cause the module to fail. Nearly all of these mechanisms are related to water ingress or temperature stress. 28. ★★Bypass diodes, used to overcome cell mismatching problems, can themselves fail, usually due to
overheating, often due to undersizing. §6
1. ★★In a stand-alone system, solar modules are usually used to charge a battery. 2. ★★Typical characteristics for each (screen printed) cell would be：Voc = 600 mV (25°C) , Isc = 3.0 A , FF = 75% , Vmp = 500 mV (25°C) , Imp = 2.7 A, Area = 100 cm2; Therefore, 36 cells in series give: Voc = 21.6 V (25°C), Isc = 3.0 A, FF = 75%, Vmp = 18 V (25°C), Imp = 2.7 A. 3. ★★★The life expectancy of solar cells is determined primarily by the quality of the encapsulation, particularly with regard to protection against ingression of moisture. 4. ★There are many types of batteries potentially available for use in stand-alone PV systems, including lead-acid, nickel-cadmium, nickel-metal-hydride, rechargeable alkaline manganese (RAM), lithium-ion, lithium-polymer and redox batteries. At present, the most commonly used is lead-acid. 5. ★★Battery maintenance can be a major limitation for stand-alone PV systems. 6. ★★Energy efficiency of battery is the product of the Charge (coulomic) and voltage efficiencies. 7. ★★★The power rating of a battery is defined as the maximum rate of charge and discharge, measured in amperes (A). 8. ★★★Battery capacity is the maximum amount of energy that can be extracted from a battery without the battery voltage falling below a prescribed value. The battery capacity is measured in kilowatt-hours (kWh) or ampere-hours (Ah), at a constant discharge rate. 9. ★★Depth-of-discharge is the percentage of the rated capacity withdrawn from the battery. Shallow cycling batteries should not be discharged more than 25% of rated capacity, while up to 80% of the capacity of deep cycling batteries may be discharged.
10. ★Lead-acid (Pb-acid) batteries are the most commonly used in present stand-alone power systems. 11. ★★★They come in a variety of types—deep or shallow cycling, gelled batteries, batteries with captive or
liquid electrolyte, sealed or open batteries. 12. ★★★Lead-calcium plates are used in VRLA/sealed batteries for low gassing rates. 13. ★★Lead-antimony batteries are usually only available as open batteries, owing to the high rate of electrolyte use and consequent need for topping-up regularly.
14. ★★★Crystals of lead sulphate grow on the battery plates during periods of low state-of-charge, reducing the
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battery efficiency and accessible capacity. This is known as sulphation. 15. ★Limiting discharge levels to a maximum of 50% can minimize this effect and keep sulphuric acid
concentration high.
16. ★The most common method of regulation and control of lead-acid batteries is based on the approximate state
of charge, measured via battery voltage. 17. ★Typical efficiencies of lead-acid batteries are as follows: (1) charge efficiency—85%, (2) voltage
efficiency—85% , (3) energy efficiency—72%. 18. ★Nickel-cadmium (NiCd) batteries are commonly used as rechargeable batteries for household appliances and can be suitable for stand-alone PV systems, especially in cold climates.
19. ★★Blocking diodes protect the battery from short circuits in the solar array, as well as preventing the batteries
from discharging through the solar cells when they are not illuminated. 20. ★Battery voltage regulators, also known as charge controllers, are needed in PV-based power systems to
protect batteries by limiting discharge levels and overcharging. 21. ★★★On reaching Voltage regulation (VR), the controller either discontinues charging or regulates the current delivered to the battery.
22. ★★★Voltage regulation hysteresis (VRH) is defined as the difference between VR and the voltage at which maximum array charging current is restored.
23. ★★★The voltage level VR – VRH is called the ‗Voltage regulation reconnect‘ (VRR). 24. ★★★Low voltage disconnect (LVD) prevents over-discharge. 25. ★★★Low voltage disconnect hysteresis (LVDH) is defined as the voltage span between the LVD and the
voltage at which load reconnection is allowable following disconnection.
26. ★★★The voltage level LVD + LVDH is called the ‗low voltage reconnect‘ (LVR).
27. ★★★For Interrupting (on/off) regulation, the controller acts as a switch, allowing all available PV current to the battery during charging.
28. ★★★On reaching VR, the controller switches off the charging current, by introducing either an open or short circuit. When the voltage falls to VRR (VR – VRH), the current is reconnected. 29. ★★★As for on/off regulation, the available charging current for Constant voltage (constant potential)
regulation is passed to the battery until VR is reached. Then however, the charging current is tapered to ensure that the battery can store all the delivered current.
30. ★★Consequently, self-regulating systems are substantially cheaper, not only because of the elimination of the
battery controller, but also because of the reduced wiring, simpler installation, and the reduced number of solar cells required.
31. ★Self-regulating systems are best suited to batteries such as nickel-cadmium that can tolerate substantial
amounts of over-charging.
32. ★★★Protection against excessive discharge basically requires disconnection of the load at the LVD point and reconnection at the LVR point after sufficient recharge. 33. ★Inverters are needed in PV-based power systems when power is required as alternating current (AC), rather than the direct current (DC) produced by the PV array.
34. ★Inverters use switching devices to convert DC to AC power, at the same time stepping up the voltage. 35. ★★★Inverters in stand-alone systems are required to supply constant voltage and frequency, despite varying load conditions, and need to supply or absorb reactive power in the case of reactive loads.
36. ★Most inverters for stand-alone PV systems include isolation transformers that separate the DC and AC
circuits.
37. ★★Batteries, regulators, inverters and other system components are collectively referred to as the balance of system, or BOS. Frequently used BOS components to be considered here include constituents of the electrical wiring system, mounting and housing. 9
38. ★★As in all electrical systems, over-current protection devices, such as circuit breakers or fuses, are needed to protect equipment and personnel.
39. ★★★Care must be taken to ensure that devices used within the DC circuit are rated for DC operation and for the potentially high DC currents possible in PV systems.
40. ★★★Switches, which may sometimes take the form of circuit breakers or fuses, are installed to isolate the array, battery, controller and load.
41. ★★Some residential systems use roof mounting, in which case a gap of at least 7 cm should be provided
beneath the modules for air flow, while some small lighting systems and telephone transmitters have their solar panels mounted on poles. 42. ★Fixed arrays are the most commonly used. 43. ★★★For mid-latitude locations, adjustment to the tilt angles every three months increases the annual energy
production by less than 5%. 44. ★★An experimental study found that insolation on an array could be increased by 18% compared to a fixed array by azimuth tracking around a vertical axis or by 11% using a tilted-axis tracker. 45. ★★Researcher measured a 30% insolation improvement relative to a fixed-tilt array. §7
1. ★★System availability (A) is defined as the percentage of time that a power system is capable of meeting the load requirements.
2. ★★★In stand-alone PV-based systems, availability depends primarily on battery size.
3. ★Typically, non-critical stand-alone systems are designed with an availability of about 95%, whereas critical systems are likely to require 99% availability. 4. ★★Telecommunication repeater stations would be considered critical, a PV cathodic protection unit may be non-critical, while low availability is acceptable for a grid-connected system. §8
1. ★Cells used in space are not protected by the earth‘s magnetic field and atmosphere and are subject to high energy particles and radiation, which reduce life expectancy to about seven years. 2. ★★★The ability of a solar cell to withstand such bombardment in space without serious degradation is known as radiation hardness. 3. ★★★Cathodic protection (CP) involves the use of an electrical current to counteract natural, corrosive electrochemical currents.
4. ★★★A 90% availability for cathodic protection would be expected to extend the life expectancy of the structure being protected by a factor of 10.
5. ★The consumer product market is already very large, and growing rapidly, concluding a wide range of watches, calculators and small toys powered by low cost amorphous silicon solar cells. 6. ★★Critical medical supplies, costing many thousands of dollars can be lost if there is a power failure to a vaccine or medical supply refrigerator. Therefore, its availability must approach 100%. 7. ★DC refrigerators of high efficiency are becoming cheaper and should be used in all applications to avoid conversion losses and the extra cost of a larger inverter, as well as to improve reliability. 8. ★★★For solar cars, efficient driving is important to ensure optimal use of the batteries and the solar input. §9
1. ★★Remote area power supply systems in non-grid areas may take on a range of configurations with a mix of possible electrical energy generating sources, plus inverters and batteries.
2. ★In many countries, new appliances, particularly refrigerators, freezers, dishwashers, air conditioners, washing
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machines and clothes dryers receive ‗energy ratings ‘, making it easier for consumers to select efficient appliances.
3. ★Power used by equipment left for long periods on ‗standby‘ is an underappreciated load that should be minimized in RAPS situations.
4. ★DC appliances are commonly more efficient and avoid the need for an inverter, with its associated loss. 5. ★The most common configuration for RAPS systems currently being installed is a photovoltaic-battery-inverter system, with a diesel or petrol generator for emergency use or for peak loads . 6. ★★For a diesel-battery or photovoltaic-diesel-battery system, batteries with appropriate characteristics must be selected.
7. ★★Many batteries commonly used in photovoltaic systems have strictly limited charging/discharging rates, which could lead to their destruction if used in a diesel system with less than three days of storage.
8. ★★★Some types of battery are only for ‗float‘ applications where they remain almost fully charged most of the time.
9. ★★★The hybrid system voltage should be selected in accordance with the inverter characteristics and requirements.
10. ★★Present generating options in remote areas not include . A. photovoltaic modules B. hydroelectric generators C. diesel or petrol generators D. grid connection 11. ★★Refrigerators and freezers can be major energy users and should be chosen carefully. 12. ★★ Microwave ovens are the only oven type suited to a RAPS system.
13. ★★As a guide, do not consider a hybrid system unless the inclusion of photovoltaics offsets at least 30%
of the estimated diesel‘s operation and maintenance costs.
14. ★The most suitable design for hybrid system will probably correspond to a photovoltaic availability of about
80% .
15. ★Stand-alone photovoltaic power systems that require availabilities in excess of 90% often need
considerable oversizing of the array for summer months and sunny days to ensure adequate electricity generation in the winter months and for periods of prolonged cloudy weather. §10
1. ★As for stand-alone PV systems, an inverter , or power conditioning unit, is needed, since photovoltaic arrays generate DC power at low voltage.
2. ★★★Two main types of inverters can be used to achieve AC power at the voltage used in the main grid. These are:
(1) Line -commutated—where the grid signal is used to synchronize the inverter with the grid.
(2) Self -commutated—where the inverter‘s intrinsic electronics lock the inverter signal with that of the grid.
3. ★★Run-on or ‗islanding‘, for instance, can result in the grid being energized, even when disconnected. Isolation
transformers are therefore commonly used.
4. ★★★The array‘s maximum power voltage at standard operating conditions must be compatible with the inverter nominal DC input voltage. The maximum array open circuit voltage should also be well within the inverter‘s tolerable voltage range. Maximum power point trackers are commonly included with grid-connected inverters to control the operating voltage of the array.
5. ★★★ inverters are designed to convert the output of all the parallel strings of modules in large arrays, with total power in the range 20–400 kW. Self-commutated designs based on insulated gate bipolar transistors (IGBTs) or field effect transistors (FETs) are now dominant.
6. ★★★ inverters accept power only from a single string, with total power in the range 1–3 kW.
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7. ★★★ inverters include various independent DC-to-DC converters, which feed their outputs to a common inverter. These allow the acceptance of power from module strings with different configurations or orientations, each able to operate at its own maximum power point.
8. ★★★ inverters sit behind individual modules, resulting in an integrated AC module.
A. Central B. String C. Multi-string D. AC module
9. ★Typically, the integral mount would be used with new construction, replacing the conventional roofing material. The use of frameless laminates can reduce costs, while solar tiles provide easy installation and a standard roof profile.
10. ★Direct mounts are secured onto the roofing material but are likely to suffer from overheating owing to
limited air flow behind the modules.
A. integral B. standoff C. rack D. direct
11. ★★★Blocking diodes protect against large current flows into shorts to ground, while over-current devices provide fuse protection in the event of failure of the blocking diode.
12. ★Grid-connected photovoltaic systems can continue to operate when the grid shuts down, a phenomenon
called ‗islanding‘, if the injected real and reactive powers are equal between production and consumption in the separated section of the grid.
13. ★★There are two basic approaches to the control of islanding via the inverter or via the distribution network. 14. ★★Disconnection must occur within two seconds of the specified islanding conditions beginning. 15. ★★The assigned capacity credit is based on the statistical probability with which the grid can meet demand. 16. ★★Apart from energy and capacity benefits, this can also give substantial ‗distributed benefits‘, such as
delaying the need for transformer, conductor or circuit upgrading, reducing transmission, distribution and transformer losses, increasing reliability and providing kVAR support in some specialized cases. §11
1. ★★In the simplest photovoltaic water pumping systems, the solar panels are directly connected to a DC motor that drives the water pump. For such simplified systems, DC motors and centrifugal pumps are virtually mandatory, because of their ability to be matched to the output of the solar panels.
2. ★★★Therefore when volumetric pumps are used, power conditioning or maximum power point tracking circuitry is commonly included between the solar panels and the motor/pump, to convert the electrical energy into a suitable useable form.
3. ★For AC motors, an inverter must be included between the solar panels and the motor. 4. ★★★Batteries have the benefit of holding the operating point of the solar panels near their maximum power points. They can thus be considered to be a ‗power conditioning‘ element in the circuit between solar panels and motor, although they may also be used to provide energy storage for a period of days during poor weather. 5. ★★★In fact, the system becomes quite complex if an AC motor is used with a volumetric pump. Batteries or power conditioning circuitry may be used to provide the high starting currents, although if batteries are used, a voltage regulator at their input and an inverter at their output to drive the AC motor, are necessary. 6. ★★★Submerged pump and motor is often used for medium depth bores with centrifugal pumps, which are then automatically primed and safer from damage and theft.
7. ★★★Submerged pump with surface motor allows easier motor maintenance but introduces reliability and efficiency problems through the mechanical drive down the bore. The reciprocating displacement pump uses a vertically-reciprocating shaft to transfer energy from the surface motor.
8. ★★★Floating pump/motor set is unsuited to boreholes but attractive for pumping from dams, canals and open wells.
9. ★★★Surface suction pump set is convenient for maintenance but can be problematic for pump priming. 10. ★★There is an abundance of names and classifications for pumps but they may all be separated into two
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categories: (1)Dynamic: in which the water velocity is continuously incremented, then reduced at the output, leading to a pressure increase. (2)Displacement(volumetric):including reciprocal and rotary types, in which energy is added periodically by forcing volume changes of an enclosure.
11. ★★★The series DC motor has a severe limitation when being driven directly by photovoltaic panels because a drop in motor current accompanying a fall in light intensity on the solar panels affects both the field and armature winding.
12. ★★★The permanent magnet DC motor greatly improves the starting torque of the motors, particularly at low light levels, and gives them excellent performance under reduced load.
13. ★★★The DC shunt motor unsuitable for direct coupling to photovoltaic panels, with the result that these
can only be used in conjunction with appropriate power conditioning circuitry.
14. ★★★The brushless DC motor tends to be more expensive but have the significant advantages of highest
efficiency and enhanced reliability, owing to the avoided need for brush replacement.
15. ★★★The role of power conditioning circuitry is to provide the motor/pump with the most suitable
voltage-current combination, while ensuring the solar panels operate at their maximum power points. 16. ★★Power conditioning circuitry must consume very little power to justify its inclusion and, in most systems,
will typically consume 4–7% of total power.
17. ★A DC-to-DC converter can again be beneficially used to produce the high starting currents by effectively converting the excess array voltage into current.
18. ★★An alternative approach commonly used for providing high starting currents is through the use of a
‗starting capacitor‘, which stores sufficient charge to provide a large current burst to start the motor/pump.
19. ★★If a MPPT is to be used, ensure internal transient protection is included, to minimize the risk of damage in the event of lightning strikes.
20. ★★★Batteries can be used effectively for power conditioning by holding the solar array at a constant voltage, which is selected to closely match the maximum power point of the solar array over the complete range of insolation levels.
21. ★★All systems using batteries should include voltage regulation circuitry to prevent the battery from
over-charging.
22. ★When AC motors are used, a DC-to-AC inverter is essential.
23. ★★Batteries may be used in water pumping systems for two independent purposes: storage of energy and as a power conditioning mechanism. 24. ★★★When batteries are to be used simply for power conditioning, nickel-cadmium batteries should be
seriously considered. The additional cost becomes less significant owing to the small quantity required, while the ability to be deep cycled, overcharged and left for long periods fully discharged, in conjunction with their longer life expectancy, robustness, greater reliability and freedom from requiring ongoing maintenance, make them well suited for such use.
25. ★★Designing a photovoltaic water pumping system has two very important aspects: Selection of the most
suitable system component types; Matching of system components。
26. ★A directly-coupled system is one where a low starting torque pump (such as a centrifugal pump) can be
driven by a DC motor that receives its power directly from the solar panels. 27. ★If the demand profile throughout the year is reasonably constant (such as for a domestic water supply), a tilt
angle in the vicinity of latitude + 20° will be necessary to give the most uniform insolation levels throughout the year falling on the solar panels.
28. ★If the amount of water to be pumped is to be reasonably constant throughout the year, but with a definite bias
towards summer months (such as for drinking water), a tilt angle in the vicinity of latitude + 10° will probably be desirable.
29. ★If the annual amount of water pumped is to be maximized (such as with a large storage reservoir), a tilt angle
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in the range latitude to latitude – 10° should be used.
30. ★If the water pumped during summer months is to be maximized (such as for some irrigation applications), a
tilt angle in the vicinity of latitude –20° will be preferable, to ensure the solar panels point more directly at the midday summer sun.
31. ★★In general, more uniform pumping throughout the year will be provided by increasing the tilt angle.
三、判断题（判断下列说法是否正确，正确T，错误F。请把答案填入答题框中相应的题号下。每小题1分，共10分。） §1
1. ★Light consisting of high energy photons (such as ―blue‖ light) has a short wavelength. Light consisting of low energy photons (such as ―red‖ light) has a long wavelength. 2. ★The photon flux alone is not sufficient to determine the current from a solar cell or specify the properties of a light source.
3. ★The radiant power density incident on the surface is the same for both the blue and red light, but fewer blue photons are needed since each one has more energy.
4. ★The photon flux of high energy (or short wavelength) photons needed to give a certain radiant power density will be lower than the photon flux of low energy (or long wavelength) photons required to give the same radiant power density.
5. ★The spectral irradiance as a function of photon wavelength (or energy), denoted by F, is the most common way of characterizing a light source.
6. ★★★Cumulus or bulky, low altitude clouds, are very effective in blocking sunlight. Cirrus, or wispy, high altitude clouds, are not as effective in blocking sunlight.
7. ★★While the units of solar insolation and solar irradiance are both a power density, solar insolation is quite different than the solar irradiance as the solar insolation is the instantaneous solar irradiance averaged over a given time period.
8. ★★Solar insolation data is commonly used for simple PV system design while solar radiance is used in more complicated PV system performance which calculates the system performance at each point in the day.
9. ★★★The most common format for solar radiation data is TMY data which includes daily variability in the data. However, average solar radiation data, particularly for each month of the year is also extensively used in rough estimates on the amount of PV panels required.
10. ★★★Steeper tilt angles are optimized for large winter loads, while lower title angles use a greater fraction of
light in the summer. §2
1. ★★★Minority carriers are created either thermally or by incident photons.
2. ★At equilibrium, the product of the majority and minority carrier concentration is a constant. 3. ★The number of minority carriers decreases as the doping level increases.
4. ★★Single crystalline wafers typically have better material parameters but are also more expensive. 5. ★★The optical and electronic properties of microcrystalline silicon are similar to those of bulk silicon.
6. ★★Since high energy light has a large absorption coefficient, it is absorbed in a short distance of the surface, while red is absorbed less strongly.
7. Light intensity exponentially decreases throughout the material and further that the generation rate is the highest at the surface of the material.
8. ★★SRH recombination, does not occur in perfectly pure, undefected material. 9. ★★An Auger recombination involves three carriers.
10. ★★★The higher the rate of recombination events, the greater the current which flows across the junction.
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11. ★★Reverse bias is applied across the device so that the electric field at the junction increases.
§3
1. ★★The quantum efficiency gives the number of electrons output by the solar cell compared to the number of photons incident on the device, while the spectral response is the ratio of the current generated by the solar cell to the power incident on the solar cell.
2. ★★Any energy above the band gap energy is not utilized by the solar cell and instead goes to heating the solar cell.
3. ★★★The inability to fully utilize the incident energy at high energies, and the inability to absorb low energies of light represents a significant power loss in solar cells.
4. ★★For an ideal solar cell at most moderate resistive loss mechanisms, the short-circuit current and the light-generated current are identical.
5. ★Significant power losses caused by the presence of a shunt resistance are typically due to manufacturing defects, rather than poor solar cell design.
6. ★The effect of a shunt resistance is particularly severe at low light levels, since there will be less light-generated current.
7. ★At low light levels, the effect of the shunt resistance becomes increasingly important. §4
1. ★★In a commercial environment where the objective is to produce a competitively priced solar cell, the cost of fabricating a particular solar cell structure must be taken into consideration. However, in a research environment where the objective is to produce a highly efficient laboratory-type cell, maximizing efficiency rather than cost, is the main consideration. §5
1. ★★The front surface of a PV module must have a high transmission in the wavelengths which can used by the solar cells in the PV module.
2. ★★In addition, the reflection from the front surface should be low.
3. ★★★Therefore, if single-crystalline solar cells are not cut squarely, the packing density of a single crystalline module will be lower than that of a multicrystalline module.
4. ★★If all the solar cells in a module have identical electrical characteristics, and they all experience the same insolation and temperature, then all the cells will be operating at exactly the same current and voltage. In this case, the IV curve of the PV module has the same shape as that of the individual cells, except that the voltage and current are increased.
5. ★A mismatch in the open-circuit voltage of series-connected cells is a relatively benign form of mismatch. 6. ★A mismatch in the short-circuit current of series connected solar cells can have a drastic impact on the PV module, depending on the operating point of the module and the degree of mismatch. 7. ★★A bypass diode is connected in parallel, but with opposite polarity, to a solar cell.
8. ★★★The cells will generate significant amounts of heat, usually higher than the module encapsulation and rear backing layer. §6
1. ★★In practice, cells encapsulated in modules usually have lower average efficiencies than unencapsulated cells.
2. ★★Sealed batteries require less maintenance than open batteries.
3. ★★★The sub-array switching topology are suitable for use in larger systems, with a number of solar array
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sections.
4. ★★★Self-regulating systems is suitable only where the climate has small seasonal temperature variations and the battery is large relative to the array size.
5. ★Efficiencies of inverters can be very low for smaller loads. 6. ★AC switches are not used for DC applications.
7. ★Lightning protection is required when a system is deemed to be prone to lighting but is usually not necessary. 8. ★The batteries themselves should never be placed directly onto concrete, as this will increase the self-discharge rate, particularly when the concrete is moist.
9. ★★Since direct solar radiation is the most effectively-concentrated, concentrator systems are suitable only for sites with characteristically high levels of direct versus indirect radiation. §7
1. ★★System costs increase rapidly in trying to obtain the last few percent of availability.
2. ★★Obviously, for many applications, particularly in remote areas, generators and PV are quite incompatible. §8
1. ★Cells used in space are not protected by the earth‘s magnetic field and atmosphere.
2. ★★Float types for cathodic protection, such as lead calcium, are not suitable, and deep cycle types, such as nickel cadmium or deep cycle lead-acid batteries are therefore used.
3. ★Self-discharge rates of the battery for solar powered cars are not critically important but the charge capacity-to-weight ratio is. §9
1. ★This oversizing of the array is very costly, but is necessary for many applications in remote areas, where maintenance and refuelling are difficult and expensive.
2. ★★★Where humans are in close proximity, PV-only availability can be reduced, usually resulting in vastly more efficient use of photovoltaics throughout the year.
3. ★★Grid-connected households use AC power for virtually all appliances. For RAPS systems, however, this may not be the most cost-effective choice. DC appliances are commonly more efficient and avoid the need for an inverter, with its associated loss.
4. ★★★LED lighting is approximately the same lighting efficiency as fluorescents and is well suited to small, low power lighting tasks.
5. ★If the hot water is heated by electricity generated by the RAPS system, connect to cold water. If your water is heated by solar collectors or a slow combustion stove, connect to hot water.
6. ★Probably the most common failure mechanism or cause for dissatisfaction with RAPS systems results from inappropriate use of the system, rather than poor system design.
7. ★Batteries used in RAPS systems with diesel generators must be of the deep-cycle type, but do not necessarily need low self-discharge rates.
8. ★★The hybrid system design should provide for infrequent use of the diesel, but for relatively long periods of time on each occasion used. §10
1. ★★★DC injection, which is inherently prevented by inverters with line-frequency transformers but not by transformerless or high-frequency transformer designs, would saturate the utility transformers and cause outages.
2. ★On-site storage is not essential for grid-connected systems, since it is possible to sell excess power to the grid
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during daylight and buy power at night. However, the addition of storage to PV systems can greatly increase their value.
3. ★The best approach in large systems is not to replace modules containing failed cells, but to design the system to be tolerant to such failures.
4. ★★Simple disconnection of large (high voltage) arrays from loads or inverters does not make them safe since they are live whenever illuminated.
5. ★Blocking diodes are not substitutes for over-current devices and are optional.
6. ★★★Both passive and active anti-islanding protection are required to prevent the situation where islanding may occur by multiple inverters providing a frequency and voltage reference for one another. §11
1. ★Volumetric pumps, often referred to as (positive) displacement pumps, have completely different torque-speed characteristics and are not well suited to being directly coupled to solar panels. 2. ★The speed of a volumetric pump is not well matched to that of an AC motor.
3. ★★Centrifugal pumps are normally used in low head/low pressure, high volume applications, particularly if direct connection to the solar panels is required.
4. ★★★Displacement or volumetric pumps are the other class of pumps often used for water pumping applications, particularly for lower pump rates from deep wells or bores.
5. ★The performance of volumetric pumps is quite poor for small heads, owing to the large component of friction.
6. ★★AC motors are very reliable and relatively inexpensive, being typically half the cost of an equivalent size DC motor.
7. ★Maximum power point tracking (MPPT) circuitry may be included in any system to boost efficiency.
8. ★For a directly-coupled PV water pumping system, no batteries, inverters, or power conditioning circuitry is used. 五、 句子英译汉题（本大题共8小题，每小题3分，共24分） §0
1. ★The understanding and exploitation of this effect was to depend on some of the most important scientific and technological developments of the 20th century. One is the development of quantum mechanics. Another, dependent on the first, is the development of semiconductor technology. 对于光伏效应的理解与探索，则是基于20世纪最为至关重要的两项科技进步之上。其一， 是量子力学的发展。其二， 是以量子论为基石的半导体技术。
2. ★Today solar cells are recognized not only as a means for providing power and increased quality of life to those who do not have grid access, but they are also a means of significantly diminishing the impact of environmental damage caused by conventional electricity generation in advanced industrial countries. 而今天，太阳能电池不再被认为只是一种提供电力和提高那些电网还没到达的偏远地区的人们生活质量的方法，而是还作为一种能显著地减少由先进工业国家造成的环境破坏的影响的方法。 §1
1. ★★★Sunlight is a form of \"electromagnetic radiation\" and the visible light that we see is a small subset of the electromagnetic spectrum. 太阳光是电磁辐射的其中一种形式，而我们看到的可见光也只是我们看到的电磁波谱的一个小子集。
2. ★Although the bulk of photovoltaic devices today are used for purely practical and economic reasons, a potential benefit of photovoltaics is that PV is one of the most environmentally benign of any electricity generating source. 尽管因为其十足的实用性和经济性，太阳能电池在今天被所人们使用着，但是使用太阳能发电的潜在好处就是，光伏发电是所有发电方式中对环境最友好的一种。
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3. ★Since the energy sector is the major producer of ―greenhouse gases‖ via the combustion of fossil fuels, technologies such as photovoltaics, which can substitute for fossil fuels, must increasingly be used. 能源领域因为其燃烧化石燃料而成为温室气体的最主要生产者，像光伏发电这种能够代替化石燃料的技术必须得到越来越多的应用。
4. ★★★The apparent motion of the sun, caused by the rotation of the Earth about its axis, changes the angle at which the direct component of light will strike the Earth. ―太阳视运动‖是由地球绕其轴自转引起的表面现象，它改变着射入地球的光线的直射分量角度。
5. ★★The power incident on a PV module depends not only on the power contained in the sunlight, but also on the angle between the module and the sun. 入射到光伏组件上的能量不仅取决于太阳光所包含的能量，还受到组件与太阳光夹角大小的影响。 §2
1. ★★Solar cells are manufactured from semiconductor materials; that is, materials that act as insulators at low temperatures, but as conductors when energy or heat is available. 太阳能电池是由半导体材料制造而成的；这种材料在低温下是绝缘体，但在有能量或热输入时就成为了导体。
2. ★★★Silicon is the most commonly used semiconductor material as it forms the basis for integrated circuit (IC) chips and is the most mature technology and most solar cells are also silicon based. 硅是使用最为广泛的半导体材料，它是集成电路（IC）芯片的基础，也是最为成熟的技术，而大多数的太阳能电池也是以硅作为基本材料的。
3. ★★★A large band gap will make it more difficult for a carrier to be thermally excited across the band gap, and therefore the intrinsic carrier concentration is lower in higher band gap materials. 宽禁带会使得载流子很难通过热激发来穿过它，因此宽禁带的本征载流子浓度一般比较低。
4. ★★★Increasing the temperature makes it more likely that an electron will be excited into the conduction band, which will increase the intrinsic carrier concentration. 通过提高温度让电子更容易被激发到导带，同时也提高了本征载流子的浓度。
5. ★★★Under most conditions, the doping of the semiconductor is several orders of magnitude greater than the intrinsic carrier concentration, such that the number of majority carriers is approximately equal to the doping. 在多数情况下，掺杂后半导体的自由载流子浓度要比本征载流子浓度高出几个数量级，因此多子的浓度几乎等于掺杂载流子的浓度。
6. ★★The cheaper multicrystalline or polycrystalline silicon (poly-silicon), and amorphous silicon are therefore increasingly being used for solar cells, despite their less ideal qualities. 价格更为低廉的多晶(包括 mc和pc) 与非晶材料正在快速广泛地被用来制造太阳能电池，尽管质量上稍逊于单晶。
7. ★★★To avoid significant recombination losses at grain boundaries, grain sizes on the order of at least a few millimeters are required. This also allows single grains to extend from front to back of the cell, providing less resistance to carrier flow and generally decreasing the length of grain boundaries per unit of cell. 晶粒尺寸的数量级至少在几个毫米大小以防止严重的晶界层复合损失。这也使得单独的晶粒从电池的正面延伸到背面，减小载流子迁移的阻力，而且电池上每个单位面积的晶界长度通常会减小。
8. ★★The high absorption coefficient of a-Si, which makes the material only a few microns thick, also means that the depletion region is large by comparison with the thickness of the emitter and base. 非晶硅的高吸收系数使得电池的材料只有几微米厚，也意味着，比起发射区和基区来，耗散区的厚度要大得多。
9. ★★★However, a-Si used in outdoor applications or under light sources with a high UV light content may experience degradation in efficiency caused by the splitting of the Si-H bond induced by UV light. 然而，在户外或在含有紫外线的光源下使用的非晶硅电池会有降低效率的可能，因为紫外线会破坏Si-H的价键结构。
10. ★★For photons which have an energy very close to that of the band gap, the absorption is relatively low since
only those electrons directly at the valence band edge can interact with the photon to cause absorption. As the
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photon energy increases, there are a larger number of electrons which can interact with the photon and result in the photon being absorbed. However, for photovoltaic applications, the photon energy greater than the band gap is wasted as electrons quickly thermalize back down to the band edges. 对于一个能量大小非常接近于禁带宽度的光子来说，其吸收的概率是相对较低的，因为只有处在价带边缘的电子才能与之作用并被吸收。当光子的能量增大时，能够与之相互作用并吸收光子的电子数目也会增大。然而，对于光伏应用来说，比禁带宽度多出的那部分光子能量是没有实际作用的，因为运动到导带后的电子又很快因为热作用回到导带的边缘。
11. ★★The number of photo-generated minority carriers outweighs the number of minority carriers existing in the
solar cell in the dark, and therefore the number of minority carriers in an illuminated solar cell can be approximated by the number of light generated carriers. 由光产生的少子的数目要远高于原本无光照时的光子数目，也因此在有光照的太阳能电池内的少子数目几乎等于光产生的少子数目。 §3
1. ★The generation of current in a solar cell, known as the \"light-generated current\
The first process is the absorption of incident photons to create electron-hole pairs, and the second process is the collection of these carriers by the p-n junction. 在太阳能电池中产生的电流叫做―光生电流‖，它的产生包括了两个主要的过程。第一个过程是吸收入射光电子并产生电子空穴对, 第二个过程是，p-n结通过对这些光生载流子的收集。
2. ★★★The \"collection probability\" describes the probability that a light generated carrier absorbed in a certain
region of the device will be collected by the p-n junction and therefore contribute to the light-generated current, but probability depends on the distance that a light-generated carrier must travel compared to the diffusion length. Collection probability also depends on the surface properties of the device. 收集概率描述了光照射到电池的某个区域产生的载流子被pn结收集并参与到电流流动的概率，它的大小取决于光生载流子需要运动的距离和电池的表面特性。
3. ★★★Under open circuit conditions, the forward bias of the junction increases to a point where the
light-generated current is exactly balanced by the forward bias diffusion current, and the net current is zero. The voltage required to cause these two currents to balance is called the ―open-circuit voltage‖. 在电池开路的情况下，pn结的正向偏压处在新的一点，此时，光生电流大小等于扩散电流大小，且方向相反，即总的电流为零。当两个电流达到平衡时的电压叫做―开路电压‖。
4. ★★★In equilibrium (i.e. in the dark) both the diffusion and drift current are small. Under open circuit
conditions, the light-generated carriers forward bias the junction, thus increasing the diffusion current. Since the drift and diffusion current are in opposite direction, there is no net current from the solar cell at open circuit. Under short circuit conditions, the minority carrier concentration on either side of the junction is increased and the drift current, which depends on the number of minority carriers, is increased. 在热平衡下（光照为零），扩散电流和漂移电流都非常小。在开路时，光生载流子引起正向偏压，因此增加了扩散电流。因为扩散电流和漂移电流的方向相反，所以开路时电池总电流为零。而电池短路时，pn结两边的少数载流子浓度以及由少数载流子决定大小的漂移电流都将增加。
5. ★Changing the light intensity incident on a solar cell changes all solar cell parameters, including the
short-circuit current, the open-circuit voltage, the FF, the efficiency and the impact of series and shunt resistances. 改变入射光的强度将改变所有太阳能电池的参数，包括短路电流、开路电压、填充因子FF、转换效率以及并联电阻和串联电阻对电池的影响。
6. ★★Concentrators have several potential advantages, including a higher efficiency potential than a one-sun
solar cell and the possibility of lower cost. The short-circuit current from a solar cell depends linearly on light intensity. The efficiency benefits arise from the logarithmic dependence of the open-circuit voltage on short circuit. 聚光太阳能电池有几个潜在的优势，包括比平板太阳能电池更高的转换效率和更低的成本。电池的短路电流大小与光的强度成线性关系，由于开路电压与短路电流呈对数关系，转换效率得以提升。
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7. ★★★The efficiency benefits of concentration may be reduced by increased losses in series resistance as the
short-circuit current increases and also by the increased temperature operation of the solar cell. 聚光电池的效率优势可能会因串联电阻的增加而有所下降，因为短路电流成线性增加，同时电池的温度也迅速上升。 §4
1. ★★Solar cell design involves specifying the parameters of a solar cell structure in order to maximize efficiency, given a certain set of constraints. These constraints will be defined by the working environment in which solar cells are produced. 太阳能电池的设计包括明确电池结构的参数以使转换效率达到最大，以及设置一定的条件。这些条件由太阳能电池所处的制造环境所决定。
2. ★★In designing such single junction solar cells, the principles for maximizing cell efficiency are: (1)increasing the amount of light collected by the cell that is turned into carriers; (2)increasing the collection of light-generated carriers by the p-n junction; (3)minimizing the forward bias dark current; (4)extracting the current from the cell without resistive losses. 为获得最高效率，在设计单结太阳能电池时，应注意几项原则：（1）提高能被电池吸收并生成载流子的光子的数量。（2）提高pn结收集光生载流子的能力。（3）尽量减小前置暗电流。（4）提取不受电阻损耗的电流。
3. ★★There are a number of ways to reduce the optical losses: (1) Top contact coverage of the cell surface can be minimized ; (2) Anti-reflection coatings can be used on the top surface of the cell; (3)Reflection can be reduced by surface texturing. (4) The solar cell can be made thicker to increase absorption; (5) The optical path length in the solar cell may be increased by a combination of surface texturing and light trapping. 下面将介绍几种能减少光损失的方法：(1)尽量使电池顶端电极覆盖的面积达到最小; (2)在电池表面铺上减反射膜; (3)表面制; (4)增加电池的厚度以提高吸收; (5)通过表面制绒与光陷阱的结合来增加电池中光的路径长度 4. ★★★By adding more than one anti-reflection layer, the reflectivity can be reduced over a wide range of wavelengths. However, this is usually too expensive for most commercial solar cells. 如果镀上多层减反射膜，能减少反射率的光谱范围将非常宽。但是，对于多数商业太阳能电池来说，这样的成本通常太高。 5. ★★★An optimum solar cell structure will typically have \"light trapping\" in which the optical path length is several times the actual device thickness, where the optical path length of a device refers to the distance that an unabsorbed photon may travel within the device before it escapes out of the device. This is usually defined in terms of device thickness. 经过结构优化的太阳电池通常拥有比电池实际厚度长几倍的光路径长度，所谓电池光路径长度是指没被吸收的光在射出电池前在电池内所走的距离。通常称它为器件厚度。
6. ★★A solar cell with no light trapping features may have an optical path length of one device thickness, while a solar cell with good light trapping may have an optical path length of 50, indicating that light bounces back and forth within the cell many times. 一个没有光陷阱结构的电池，它的光路径长度可能只相当于电池实际厚度，而经过光陷阱结构优化的电池的路径长度能达到厚度的50倍，这意味着光线能在电池内来回反弹许多遍。
7. ★★★Typically, recombination at the surface (surface recombination) or in the bulk of the solar cell (bulk recombination) are the main areas of recombination. The depletion region is another area in which recombination can occur (depletion region recombination). 一般来说，发生在电池表面（表面复合）和电池体内（体复合）的复合是主要的复合形式。而耗尽区则是另外一个会发生复合的区域。
8. ★★★The presence of localized recombination sites at both the front and the rear surfaces of a silicon solar cell means that photons of different energy will have different collection probabilities. 电池的前表面和背表面存在局部复合区域，意味着能量不同的光子将有不同的收集概率。
9. ★★★A detrimentally low shunt resistance is a processing defect rather than a design parameter. However, the series resistance, controlled by the top contact design and emitter resistance, needs to be carefully designed for each type and size of solar cell structure in order to optimize solar cell efficiency. 有害的低并联电阻是一种制造缺陷，而不是参数设计的问题。然而，由顶端电极电阻和发射区电阻组成的串联电阻就跟并联电阻有所不同，必须小心设计电池结构的类型和尺度以优化电池的效率。
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10. ★★★The design of the top contact involves not only the minimisation of the finger and busbar resistance, but
the overall reduction of losses associated with the top contact. These include resistive losses in the emitter, resistive losses in the metal top contact and shading losses. The critical features of the top contact design which determine how the magnitude of these losses are the finger and busbar spacing, the metal height-to-width aspect ratio, the minimum metal line width and the resistivity of the metal. 顶端电极的优化设计不只有子栅和母栅电阻的最小化，还包括与顶端电阻有关的总的损耗的最小化，即包括发射区的电阻损耗、金属电极的电阻损耗和阴影损耗。一些设计的因素决定了损耗规模的大小，它们包括子栅和母栅的间距、金属的宽高横纵比、金属栅条的最小宽度以及金属的电阻率。
11. ★The overriding reason for this difference in efficiency is that the research techniques used in the laboratory
are not suitable for commercial production within the photovoltaic industry and therefore lower cost techniques, which result in lower efficiency, are used. 造成两者差别这么大的最主要原因为实验室使用的研究技术并不适用于现代商业制造中，因此低成本导致低效率。
12. ★For a given module cost, more efficient modules are also more cost effective because fewer additional costs
(such as lade area, wiring costs, etc.) are needed to generate the same amount of power. Ultimately, this means that the more efficient a PV module is, and thus the more cost effective it becomes, the more attractive photovoltaics will be as an electricity source for both domestic and industrial use. 对于给定成本的电池板来说，效率更高代表成本效益更好，因为生产同等电力所需额外的成本减少了（比如运输成本、电路系统成本等）。最终，也意味着效率更高、经济效益更高的太阳能电池对住宅和工业用电系统都更具吸引力。 §5
1. ★A PV module consists of individual solar cells electrically connected together to increase their power output. They are packaged so that they are protected from the environment and so that the user is protected from electrical shock. 一块光伏组件是由许多单个太阳能电池连接而成的，这样能增加功率输出。电池被封装起来以阻止来自周围环境的破坏和防止人们触电。
2. ★★The most important effects in PV modules or arrays are:(1)losses due to the interconnection of mismatched solar cells;(2)the temperature of the module;(3)failure modes of PV modules. 光伏组件或阵列最主要的影响是：(1)不匹配的电池之间的互联引起的损耗；(2)光伏组件的温度；(3)光伏组件的故障模式。 3. ★★The two key functions of encapsulation are to prevent mechanical damage to the solar cells and to prevent water or water vapor from corroding the electrical contacts. 封装的两个主要功能是保护太阳能电池不受机械破坏以及电极不受水或水蒸气腐蚀。
4. ★★For two cells connected in series, the current through the two cells is the same. The total voltage produced is the sum of the individual cell voltages. 对于两个互相串联的电池来说，流过两者的电流大小是一样的。产生的总电压等于每个电池的电压的总和。
5. ★★An easy method of calculating the combined short-circuit current of series connected mismatched cells. The current at the point of intersection represents the short-circuit current of the series combination. 这是计算串联电池的错配短路电流的一个简单方法。两线交点的电流表示串联电路的短路电流。
6. ★However, if a solar cell is reverse biased due to the a mismatch in short-circuit current between several series connected cells, then the bypass diode conducts, thereby allowing the current from the good solar cells to flow in the external circuit rather than forward biasing each good cell. 然而，如果串联电池中有一个电池因为发生错配而导致电压被反向偏置，则旁路二极管就会立即导通，因此使得来自好电池的电流能流向外部电路而不是变成每个电池正向偏压。
7. ★★In practice, however, one bypass diode per solar cell is generally too expensive and instead bypass diodes are usually placed across groups of solar cells. 然而，实际上如果每个电池都连接一个二极管的话，成本会很高，所以一般改为一个二极管连接几个电池。
8. ★★★An easy method of calculating the combined open circuit voltage (Voc) of mismatched cells in parallel. The curve for one of the cells is reflected in the voltage axis so that the intersection point is the Voc of the
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parallel configuration. 有个简单的方法可以计算错配并联电池的开路电压，即在坐标图中以电压为自变量画出IV曲线，则两线的交点就是并联电路的开路电压。
9. ★Parallel connections in combination with mismatch effects may also lead to problems if the by-pass diodes are not rated to handle the current of the entire parallel connected array. 如果旁路二极管的额定电流与整个并联电路的输出电流大小不匹配的话，则并联电路的错配效应同样会导致严重的问题。
10. ★With parallel connected modules, each string to be connected in parallel should have its own blocking diode.
This not only reduces the required current carrying capability of the blocking diode, but also prevents current flowing from one parallel string into a lower-current string and therefore help to minimize mismatch losses arising in parallel connected arrays. 在互相并联的组件中，每个组件都串联一个阻塞二极管。这不仅能降低驱动阻塞二极管的电流，还能阻止电流从一个好的电池板流到有问题的电池板，也因此减小了并联组件的错配损失。
11. ★★★The operating temperature of a module is determined by the equilibrium between the heat produced by
the PV module, the heat lost to the environment and the ambient operating temperature. 组件的工作温度决定于组件产生的热量、向外传输的热量和周围环境的温度之间的平衡。
12. ★★The heat produced by the module depends on the operating point of the module, the optical properties of
the module and solar cells, and the packing density of the solar cells in the PV module. The heat lost to the environment can proceed via one of three mechanisms: conduction, convection and radiation. 组件产生的热量决定于组件所在的工作点、组件的光学特性和电池的封装密度。组件向外散发热量可以分为三个过程：传导、对流和辐射。
13. ★★★The factors which affect the heating of the module are: (1) the reflection from the top surface of the
module; (2) the electrical operating point of the module; (3) absorption of sunlight by the PV module in regions which are not covered by solar cells; (4) absorption of low energy (infrared) light in the module or solar cells; (5) the packing density of the solar cells. 影响组件的热生成的几个因素包括：（1）组件表面的反射；（2）组件所处的工作点；（3）组件中没有被电池片占据的空白部分对阳光的吸收;（4）组件或电池对低能光（红外光）的吸收；（5）太阳能电池的封装密度。
14. ★★★The operating temperature of a PV module is an equilibrium between the heat generated by the PV
module and the heat loss to the surrounding environment. 光伏组件的工作温度是组件所产生的热量与向外界传输的热量之间的动态平衡。
15. ★★★Degradation mechanisms may involve either a gradual reduction in the output power of a PV module
over time or an overall reduction in power due to failure of an individual solar cell in the module. 老化机制即可能是由于时间的流逝而导致整体输出功率的减小，也可能是由于组件中个别太阳能电池的恶化而导致总输出功率的减小。
16. ★★★A gradual degradation in module performance can be caused by: (1) increases in RS due to decreased
adherence of contacts or corrosion (usually caused by water vapor); (2) decreases in RSH due to metal migration through the p-n junction; (3) antireflection coating deterioration. 引起电池组件的整体老化的因素：(1)电极接触面积的减小和腐蚀（通常由水蒸气引起）导致RS增加; (2)穿过pn结的金属漂移使Rsh减小; (3)减反射膜的老化。 §6
1. ★★Grid-connected applications are of increasing interest and have now overtaken stand-alone systems as the main market for photovoltaic modules worldwide. 并网发电应用正在日益发展并且现已超过系统，成为光伏市场的主力军。
2. ★★The cost-effective region for using a stand-alone system, versus connecting to the grid, varies with load, distance from the grid and the stand-alone system chosen. The design of a stand-alone PV-based power system is determined by the location, climate, site characteristics and equipment to be used. 同并网发电相比，光伏系统的成本效率随着电网的负载、离电网的距离和系统本身的设计而变化。基于光伏系统的电力
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系统，其设计由地点、气候、地理特征和设备选择所决定。
3. ★★A module Vmp of 18 V is required when charging a 12 V lead-acid battery because: (1)~2.8 V is lost to temperature rises to 60°C; (2)A drop of ~0.6 V occurs across the blocking diode; (3)A drop of 1.0 V typically occurs across the regulator; (4)There can be some voltage loss with reducing light intensity; (5)The batteries must be charged to 14.0–14.5 V to reach their full state of charge. 为一个12V的铅酸蓄电池充电，需要使用Vmp =18 V的组件，这是因为：（1）当太阳能电池工作温度升到60℃时电压损失约2.8 V；（2）通过阻塞二极管时电压下降0.67V；（3）通过稳压器时通常电压下降1.0V；（4）光照强度不足的情况下电压也会下降；（5）要使蓄电池完全充足电，需要14.0-14.5V。
4. ★★★Batteries can be used for: （1）Power conditioning (e.g. in water pumping systems)；（2）Short-term storage, to effectively redistribute the load over a 24 hour period；（3）Longer-term storage, to ensure system availability throughout periods of low insolation. 蓄电池可以用作：（1）维持系统运行(如水泵系统)；（2）周期性短期存储，以便更有效地分配电力(如以24小时为一循环)；（3）为保证系统能够度过低日照月份而进行长期存储。
5. ★★Typical requirements for a battery system to be used for long term storage are: （1）long life；（2）very low self-discharge；（3）long duty cycle (long periods of low charge) ；（4）high charge storage efficiency ；（5）low cost；（6）low maintenance.对必须长期运行的蓄电池系统来说，主要需要满足以下特征：（1）寿命长；（2）较低的漏电量；（3）较长的负载周期和 (长期低电量使用)；（4）比较高的充电效率；（5）低价格；（6）低维护。
6. ★★★Battery capacity is affected by temperature, falling by about 1% per degree below about 20°C. At the other extreme, however, high temperatures accelerate aging, self-discharge and electrolyte use. 蓄电池的容量还受温度影响，在20℃以下时温度每降低1℃容量大约会下降1%。然而在另一端，高温会加速蓄电池的老化、漏电以及电解液消耗。
7. ★Since battery life is a function of the average state of charge of the battery, a compromise must be made when designing a system between cycling depth and size of the battery. 因为蓄电池寿命受蓄电池的平均充电状态所影响，因此我们在设计一个系统时必须协调好电池的循环深度和容量之间的关系。
8. ★★★If VRH is set too large, there will be long interruptions to charging. If VRH is set too small there will be frequent oscillations, possibly with noise and with the potential to damage the switching elements. 如果滞后电压设置得太大。充电就会被长时间中断。如果滞后电压设定得太小那么电路就会在断开与闭合之间作频繁的振动，可能造成噪音并且有可能损坏开关组件。
9. ★★★If LVDH is set too small, the load cycles on and off rapidly at low battery state of charge, possibly leading to controller and/or load damage. If it is too high, the load will remain off for extended periods. 如果开路滞后电压设定得太小，在低电位上负载电路会非常迅速地开合，可能导致控制器和负载受损。然而如果设得太高，电路则会长时间保持关闭状态。
10. ★If left on, inverters can continue to draw significant power, even with no load. This can rapidly run down
solar-charged batteries, so that systems with an inverter must incorporate some means of inverter control, if this is not built-in. 如果不将逆变器关闭，就算没有负载连接它也会不断地消耗大量能量，这样会迅速耗尽蓄电池里的电能。所以如果逆变器里没有集成一个控制电路的话，我们就必须自行在系统中加入一些逆变控制器件。
11. ★★★Preferred requirements for inverters in stand-alone PV systems are: (1) large input voltage range; (2)
voltage waveform close to sinusoidal; (3) tight control of output voltage (±8%) and frequency (±2%); (4) high efficiency for low loads (>90% at 10% load); (5) tolerance of short overloads, particularly for motor starting ; (6) good behaviour with reactive loads; (7) tolerance of loads that use half-wave rectification; (8) tolerance of short circuits. 在光伏系统中，对逆变器的要求如下：（1）可承载的输人电压范围较大;（2）电压波形近似于正弦波;（3）输出电压（士8%以内）以及频率（士2%以内)误差小;（4）低负载工作时保持高效率〔10%负载时效率最好达到90%以上);（5）能够承受瞬时过载(尤其在电机启动时);（6）自动针对负载变化作出恰当调整;（7）适用于设置了半波整流的负载;（8）不易短路。
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12. ★★★Ideally, copper wire should always be used in PV power systems, although it is more expensive than
aluminium wire. However, given the cost difference, aluminium wire may be acceptable for very long runs. 虽然铜制导线比铝制导线价格更高，但太阳能系统中一般会使用铜制导线。然而，出于成本的考虑，也可以在超长距离使用铝线。 §7
1. ★Design of a stand-alone PV system centers on the selection and sizing of appropriate components to meet the requirements of a particular load. Component costs and efficiencies are required, in addition to load characteristics. 光伏系统设计的核心在于根据特定负载的需求来选择适合的配件。除了负载的特征，同时也需要考虑组件成本及其工作效率。
2. ★★Trade-offs can usually be made between components to meet budget constraints, although system reliability and life expectancy are likely to be compromised. 尽管系统的可靠性和使用寿命会受到影响，但往往由于预算，在实际设计中不会采用最佳性能的配置。
3. ★★★Depending on the situation, major design criteria may include: (1) lowest life cycle cost—this can be three times the initial investment cost, with extensions of battery life having a strong impact on its reduction; (2) tolerance of load and insolation variations;(3) modularity and flexibility;(4) ease of maintenance and repair ; (5) quality of power supply; (6) Reliability;(7) social factors. 根据不同情况，主要的设计准则包括以下几点：（1）最低寿命周期成本——可达初期投资成本的三倍，如果能尽量延长电池寿命则将极大地压缩后期维护费用；（2）允许负载和阳光辐照量的波动；（3）设计的模块化和灵活性；（4）维护和修理的简易程度；（5）输出电能的品质；（6）可靠性;（7）社会因素。
4. ★In designing a system, the requirements of each specific application, solar variability at the site and financial limitations will determine the appropriate availability. 在光伏系统的设计过程中， 根据每套系统的确切用途，该系统所处地区的日照变化情况，以及工程顶算的决定了这套系统应该具备多高的利用率。 5. ★★For normal power systems, such as for households, the general approach is to design a system with non-critical availability, increasing the system components later if necessary and as more finance becomes available. 一般性电力系统，如家用太阳能系统，可先按照非关键设备标准来设置其系统利用率，使用时如果必须提高利用率，则可逐渐升级系统配置，届时资金压力也许可以得到缓解。
6. ★In some applications, it is both economical and desirable to use a hybrid system, whereby the PV supplies some or most of the load, but with a diesel or petrol generator as a backup. 在一些项目中使用混合能源系统是一个既稳定、节能，又经济划算的选择。该系统用光伏发电来满足部分或绝大部分的电力负载需求，并使用柴油或汽油发电机作为备用。 §8
1. ★Many space cells are made from gallium arsenide and related compounds, rather than silicon, yielding higher efficiency but at much higher cost. 很多空间用太阳能电池采用砷化镓以及相关化合物制作，砷化镓电池与晶体硅太阳能电池相比具有更高的光电转换效率，但是需要更高的成本。
2. ★★★Although PV battery systems are preferred, hybrid systems are sometimes used. These use a diesel generator to provide less than 10% of the annual power requirement, but significantly reduce the necessary solar array and battery size and ensure system availability approaches 100%. The resultant cost reduction further increases the cost-effectiveness of photovoltaics, although increased maintenance for such systems is inevitable, such that these hybrid systems are not suited for use in very remote areas. 尽管在这方面的应用中，光伏发电-蓄电池能源供应系统是能源供应系统的首选，有时也会采用混合能源供应系统。混合能源供应系统采用柴油发电机提供中继站全年所需能源的10%，它最显著的作用是减少了对光伏组件以及蓄电池的需求，并且确保了中继站的运行率达到近100%。这节约了太阳能电池能源系统的成本，但是同时也为系统的维护增加了成本，因此混合能源供应系统不适合在过于边远的地区使用。
3. ★★★During operation, a controller is virtually essential in a CP system, to adjust the current so as to keep the
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reference voltage on the metal structure constant (i.e. control the current to overcome the varying electrochemical potential). 在实际操作过程中，控制器是阴极保护电路的核心部分，它用来调整电流以适应参考电压从而使金属结构保持恒定(也就是调整电流来适应变化的电化学电势)。
4. ★★★Vandalism and theft are also problems. For these reasons, pole mounting is preferable, but can lead to increased wiring losses and higher installation costs, unless specially-designed integrated systems are used. 在应用过程中由于人为破坏以及盗窃问题的存在，使用杆支式的光伏系统更有优势，但是这样会增加电缆的长度而导致能源损耗并且会增加光伏发电系统的成本，除非使用特殊设计的集成系统。
5. ★★★Markets for photovoltaic-powered cathodic protection systems will continue to grow as a better understanding of photovoltaic systems is gained, as photovoltaic prices fall and as metal coatings improve in quality. The latter results in higher integrity factors, which would therefore reduce loads, making photovoltaic systems more economical. 随着光伏系统供电的优势被越来越多的人所理解，光伏供电系统成本的下降以及金属镀层质量的提高，光伏供电阴极保护系统的市场将越来越好。最终的结果就是产生低载荷、高完整性因子、更加经济的光伏发电阴极保护系统。
6. ★Photovoltaics offer low maintenance, cleanliness, ease of use and installation, reliability, long life, unattended operation, and can be easily matched to any need. 光伏发电系统具有很多优良特性，包括低维护性、清洁、便于使用和安装、高可靠性、长寿命、无须人员操作并且可以轻易地适用于各种需要。 7. ★Where rechargeable batteries are already used as a power source, solar modules can be used to keep the batteries fully charged during periods of reduced use, compensating for self-discharge. 在使用可充电电池作为电源的场合，太阳能电池组件可以在电量不足的时候用于充电以保证电量的充足，还可以用来弥补充电电池的自放电。
8. ★Photovoltaics is particularly attractive because of its high reliability, non-dependence on fuel supplies, long life and low maintenance. However, some level of continuing support, education and training of users is necessary to avoid a high incidence of system failures. 光伏发电由于可靠性高、无燃料依赖、寿命长以及维护费用低而显得非常吸引人。但是，用户的持续支持、对用户相关知识的教育和培训是必需的，这样可以避免系统的高失效率。
9. ★★★It is likely to be many years before large numbers of regular commuter vehicles are powered by photovoltaics, owing to the need for: (1) cost reductions; (2) on-road compatibility with other vehicles, such as trucks; (3) acceptance by transport authorities, particularly on the grounds of safety; (4) standardized, reliable designs; (5) consumer acceptance; (6) mass-produced low-weight solar panels; (7) regenerative braking, which is necessary to maintain efficiency where frequent stopping occurs; (10) establishment of recharging stations. 目前，在市场上出现太阳能驱动的汽车可能还需要很多年，是由于需要：(1) 降低成本;(2) 和其他交通工具的道路的兼容性，比如卡车;(3) 运输部门的认可，尤其在安全性方面;(4) 相关的标准化、可靠性设计;(5) 消费者的认可;(6) 大批量生产的轻型太阳能电池组件;(7) 制动能量回馈，在频繁停车发生的情况下保持效率; (8) 建立充电站。
10. ★★★Although gradually improving in quality, many of the photovoltaic-powered garden lighting kits
marketed over the last decade tend to be gimmicky and unsuitable for their intended use for any reasonable period of time. 尽管产品的质量在逐步地改进，但是过去十年中，很多市面上销售的光伏庭院灯套装一般偏重设计新潮而忽略了使用时的实用价值。
11. ★★★Since fluorescent lamps are over four times more efficient than incandescent lamps, they are preferred
in photovoltaic systems. 荧光灯的效率是普通白炽灯的4倍，因此在光伏照明系统中应当选用荧光灯。 12. ★★With any monitoring system, power is required for the instrumentation and the data communications
equipment. Since these power requirements are typically quite low (loads can often be measured in mAh per day), monitoring applications are ideal for photovoltaic systems. 任何一个监测系统都需要使用电，因为仪器使用的需要以及数据传输的需要。由于这些电能的需求一般都非常低(每天负载通常以mAh为单位)，所以光伏发电系统成为监测系统的理想电源。
13. ★PV systems can be connected directly to the load, typically using only one module. Such direct-drive
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systems have considerable appeal, as they avoid the use of batteries, blocking diodes, and all power conditioning circuitry. 光伏系统可以直接连接到负载。通常这样的情况只使用一个太阳能电池组件。这样的直接驱动系统值得推荐，这是因为它避免使用蓄电池、阻塞二极管以及其他相关电源控制电路。 §9
1. ★★Stand-alone photovoltaic power systems that require availabilities in excess of 90% often need considerable oversizing of the array for summer months and sunny days to ensure adequate electricity generation in the winter months and for periods of prolonged cloudy weather. 当式光伏电力系统供电需要保证系统利用率在90%以上的时候，通常必须考虑到太阳能阵列的面积是否够大，以确保在冬天的月份或是长期阴雨天气时仍有足够的发电量。
2. ★To maximize the efficiency of photovoltaic use in the system, it is necessary that all generated electricity be used either directly by the load, or be stored in the batteries. 为了要提升系统使用光伏的效能至最大，负载必须直接使用掉全部光伏的发电或者直接由蓄电池储存所有的发电。
3. ★★★House design and orientation, as well as selection of appropriate energy sources and appliances for different end uses, such as cooking, heating and lighting, are of critical importance when using a RAPS system. 当采用偏远地区的供电系统时，房屋的设计、方位以及为不同的电器选择适当的能源供给，诸如烹饪、取暖和照明等，是至关重要的。
4. ★★A combination of AC and DC wiring has advantages when considering the range of available appliances and their relative efficiencies, but may introduce safety problems and complications during maintenance. 同时采用交流和直流可以有助于优化选择各种用电器及其相对效率，但是这可能会带来安全方面的问题，增加维修的难度。
5. ★★★In general, the most important design criterion for a RAPS system is to avoid the use of electrical appliances wherever possible, in favour of non-electrical substitutes. 一般来说，偏远地区光伏供电系统(RAPS)中最重要的设计标准是尽可能避免使用电器产品，并尽可能采用非电器类的替代产品。
6. ★The most common configuration for RAPS systems currently being installed is a photovoltaic-battery-inverter system, with a diesel or petrol generator for emergency use or for peak loads. 目前最为常见被安装的RAPS系统配置是光伏-蓄电池-逆变器系统，而柴油或汽油发电机是为了峰值负载时的应急之用。
7. ★Despite the high initial costs, where diesels are currently used, the addition of solar panels, batteries and controller can greatly improve the efficiency of generator usage as well as substantially reducing system operating costs. Conversely, a diesel generator removes the need for oversized photovoltaic arrays, which would be both costly and poorly utilized. 尽管初期成本较高，然而当前在使用的柴油发电机加上太阳能板、蓄电池和控制器可以大大提高发电机的工作效率以及大幅降低系统的营运成本。反过来说，安装一个柴油发电机可以避免超额添置光伏阵列的必要，因此省下许多开销并避免了太阳能板的闲置。
8. ★Some of the costs that need to be considered include system components—photovoltaic array, batteries, inverter, tracker, generator, wiring, control boards and regulators. In addition, the fuel costs for diesel and petrol generators must be estimated, as must the installation costs, maintenance costs and lifetimes for all components, which will vary. 一些系统组件的费用支出，包括光伏阵列、蓄电池、逆变器、、发电机、电线、控制板和稳压器等都必须要加以考虑。同时，柴油和汽油发电机的燃料花费、安装费用、维修费用和所有配件的使用寿命都必须予以估计。
9. ★★Inverters are expensive and where possible should be downsized from the peak loads by having periods of peak demand coinciding with periods of diesel or petrol generator usage. 逆变器的价格高昂，如有可能应将已达到需要使用柴油或汽油发电机的时段或使用尖峰时段的峰值负载的规模缩小。
10. ★An increased tilt (i.e. greater than the latitude) gives more uniform all-year-round generation, but at the
expense of total annual output. 增加倾斜角度〔即使倾角大于纬度角)会让全年的发电量更为均匀，但是其代价为年总发电量会降低。
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11. ★★For a photovoltaic-diesel hybrid system, downgrade the availability/array size so that on a clear sunny day
in summer, at the design tilt angle, the electrical energy generated (allowing for subsystem inefficiencies) just matches or is slightly less than that consumed by the load over a 24 hour period. 在给定的设计倾角下，适当减小光伏-柴油混合系统的太阳能组件面积和系统利用率。减少的尺度为:在晴朗的夏日，光伏发电量刚好满足或略少于负载24 h的消耗(需考虑低效能的子系统)。
12. ★★★If less photovoltaics is desired (to cut system costs), the array tilt angle should be decreased to provide
greater annual electrical energy generation. This will boost summer generation at the expense of winter generation but will reduce overall diesel operating time and hence O&M costs. 如果需要较少的光伏（以降低系统成本)，阵列的倾角应减少并能提供更大的全年总发电量。这将使得夏季的发电量突增但必须牺牲掉冬季原来的发电量，但整体来说将会降低柴油发电机的总的工作时间，连带性地降低了柴油发电机的工作成本和维护开销。
13. ★★There are numerous situations where portable RAPS systems can be of value owing to their independence
of existing infrastructure, speed of installation and their modularity. 便携式RAPS系统能够不需要配套基础设施就可以运作，具有快速安装以及模块化的特点，因此在很多场合具有使用价值。 §10
1. ★Photovoltaics can be used in grid-connected mode in two ways: as arrays installed at the end use site, such as on rooftops, or as utility-scale generating stations. 光伏并网发电可以通过两种模式来实现：将太阳能板安置于用户终端(如安装在民居屋顶)或者是集中建设大型光伏发电站。
2. ★For a household system, the essential components are: PV modules, a grid-interactive inverter, so that the electricity is utility-compatible, and metering equipment to feed and measure the power exchange between the house and the grid. 对于一般的家庭应用来说，典型光伏系统的主要组成部分包括：光伏组件(即太阳能板)、并网交互逆变器(保证系统输电与电网的兼容性)和电表(用以记录和反馈系统与电网之间的能量交换)。
3. ★On-site storage is not essential for grid-connected systems, since it is possible to sell excess power to the grid during daylight and buy power at night. However, the addition of storage to PV systems can greatly increase their value. 对于并网发电系统来说本地存储并非不可或缺，因为它可以在白天把多余的能源卖给电网上的其他用户，然后在晚上从电网提取电能。
4. ★★However, the addition of storage to PV systems can greatly increase their value. Storage can be provided on site, typically via batteries or, for larger systems, via pumped hydro, providing storage for peak period use. 尽管如此，在光伏系统中加装蓄电设备可以极大地提高其实际应用价值。存贮器可以直接安置在光伏系统附近，一般会选择蓄电池。大型系统也可以通过泵把电力转化为水的势能，留待用电高峰期来临时作以补充。
5. ★★On-site storage can also be used as a demand-side management tool, to reduce peak load power requirements, and hence costs, for the building as well as providing high value peak load power to the grid. 本地储存系统同样可以作为对电力需求的控制手段，从而来缓解用电高峰期的供电压力，同时也可以在用电高峰期对电网的电量进行补充。
6. ★★★To keep costs down, more emphasis needs to be placed on simplification of design, provision for maintenance, standardization, and in-built protection and control systems. 为了控制最终的系统预算，有许多重要的地方需要注意改善，如简化设计、维修服务、产品的标准化、防护设备的配套和操作系统等。 7. ★★Despite the apparent opportunities and benefits of PV use, most electricity utilities are faced with a number of perceived risks, which they have no historical basis for quantifying, when assessing the feasibility of photovoltaic systems. 尽管太阳能技术的前景和利润预期非常诱人，但实施一个项目要面对许多风险，尤其是对于光伏系统这样的新技术来说，设计者缺乏足够的经验、数据和范例。
8. ★★Many safety issues are common for building-integrated, building-mounted or central station grid-connected PV systems. Safety aspects that need to be considered include fire resistance, correct wiring,
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placement, grounding, and security against local weather conditions, particularly wind. 对于安装在建筑物上的光伏系统，或并网光伏电站来说，安全问题至关重要。我们需要考虑的安全问题主要包括：防火、正确布线、安置地点的选择、接地以及对气候变化尤其是强风的防范措施。
9. ★The value to the grid of PV-generated electricity depends largely on the time of day when the grid experiences peak demand. Electricity supplied during this peak can be worth 3–4 times that generated ‗off-peak‘. 太阳能发电在电网中的价值和当地电力需求高峰期出现的时间有很大关联。光伏电能在用电高峰时段所创造的价值可达平时的3-4倍。
10. ★By generating electricity locally, the amount of power to be transmitted along the distribution line is reduced,
delaying the need for upgrading. In addition, just by reducing the current through a transformer prior to its peak load, its lower temperature allows it to carry a higher peak without overheating. 本地化的发电模式，使得通过电线来传送的电能的总量被减少，并且延长了设备使用寿命。除此之外，减小流过变压器的电流也会降低其温度，进而使变压器在更高峰值出现的时候能导通更大的电流，而不会有过热的危险。
11. ★PV can also be used for demand side management, to the benefit of both the utility and customer. For
instance, PV systems on the rooftops of large electricity users can reduce peak load energy and demand. 太阳能发电还可以被用来管理用电需求。这对公共电网和消费者来说都有好处。例如，在用电量较大的建筑物屋顶上安装光伏系统，就可以有效降低其在用电高峰期对电网供电的依赖。 §11
1. ★★Water pumping applications can vary widely, both in their requirements and in the conditions under which the pumping must take place. Considerable variability exists in volumes of water required, timing of water requirements, water source capacity, depth from which it is to be pumped, replenishment rates of the source, seasonal variability of static head, bore or well diameters, and solar insolation characteristics. 由于使用条件的制约，水泵的应用与配置方法种类繁多。所需水量、用水时间、水源容量、抽水深度、水源补给率、季节变化对静压头的影响、井口直径，以及基本日照数据等众多因素都必须加以考虑。
2. ★★★Selection of the most suitable components and configurations for each specific application and site is critical to the economic viability and the long-term performance of the system. 设计者要能够针对每个具体的地点和项目来选择最适合的系统结构和系统部件，这对于项目的经济可行性及系统的长期表现而言至关重要。
3. ★★Batteries for energy storage are sometimes a necessity in such systems, particularly if it is critical that pumping take place at specific times, if pump rates exceed replenishment rates for the water source, or even to provide power conditioning for the pump/motor. 在光伏水泵系统中，有时需要使用蓄电池来储存能量。比如说，当用户必须在某些特定时段抽水时，或是当抽水速率超过水源的加注率时，甚至在需要对水泵电动机进行功率时，都可以通过使用蓄电池来实现。
4. ★Where possible, however, the use of batteries or other forms of storage should be avoided because of their relatively short life expectancies, requirements for maintenance, poor reliability, high cost, their need for protection by a voltage regulator and for environmental reasons. 但是，如果可能的话，应该尽量避免使用蓄电池或其他形式的储能设备，因为它们相对系统其他配件来说寿命短、需要维护、可靠性低、价格高昂，并且依赖充电控制器来保护其正常运行，除此之外还有环保等其他问题。
5. ★★In particular, small motors of about 1 kW or less suffer from very low efficiencies, making them not well suited to photovoltaic-powered systems. In addition, they require costly inverters at their inputs, which can exacerbate reliability problems. Furthermore, to provide high starting currents, additional power conditioning circuitry is generally required. 特别是那些小型交流电机(功率等于或小于1 kW)，其工作效率非常之低，以至于无法适用于光伏动力系统。此外，交流电动机还需在输人端加装一个昂贵的逆变器，这还可能造成系统稳定性降低。再者，为了提供高启动电流，还需要额外的功率调节电路。
6. ★★When batteries are to be used simply for power conditioning, nickel-cadmium batteries should be seriously considered. The additional cost becomes less significant owing to the small quantity required, while
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the ability to be deep cycled, overcharged and left for long periods fully discharged, in conjunction with their longer life expectancy, robustness, greater reliability and freedom from requiring ongoing maintenance, make them well suited for such use. 若蓄电池仅仅是用来作为电力调节设备的话，那么就应优先考虑镍镉电池。因为电力调节需要的数量不多。并且镍镉电池具有深度放电、可过充、长时间处于低电压不充电也不会报废、相对使用寿命较长、稳定可靠以及不需要日常维护等优点，这样，加装蓄电池的额外的成本就显得比预期的低很多，并且非常适合电力调节应用。
7. ★★★The general approach to designing a system can be summarized as follows: (1)Determine the volume of water to be pumped each day, and at what head; (2)Calculate the pump rate from the number of sunlight hours; (3)Select the pump type; (4)From the torque-speed characteristic of the pump, select a motor with a compatible torque-speed characteristic; (5)Select appropriate solar modules; (6)Select module mounting method—fixed or manual tracking. 一般设计一个系统的流程可以总结如下：(l)确定每天要抽取的水量以及其扬程大小；(2)从日照小时的时数计算抽取速率；(3)选择合适的水泵种类；(4)依照泵的扭矩与速度的特性，选取一个能兼容此特性的电动机；(5)选择适当的太阳能组件；(6)选择组件安装方式（固定或跟踪）。
六、案例分析题（本大题共8小题，每小题3分，共24分） §1 1. ★
ShorizontalSincidentsinSmoduleSincidentsin
where is the altitude angle of the sun at noon, and is given by
=90--（Facing south in the Northern hemisphere） =90--（Facing north in the Southern hemisphere）
β is the tilt angle of the module measured from the horizontal, is the latitude; and is the declination angle.
SmoduleShorizontalsinαβsinα
§2
2. ★★The following table summarizes the properties of semiconductor types. Dopant Bonds Majority Carriers Minority Carriers 3. ★
29
P-type (positive) Group III (E.g. Boron) Missing Electrons (Holes) Holes Electrons N-type (negative) Group V (e.g. Phosphorous) Excess Electrons Electrons Holes
Cross section of a solar cell.
4. ★★The collection probability of carriers generated in the depletion region is unity as the electron-hole pair
is quickly swept apart by the electric field and are collected. Away from the junction, the collection
probability drops. If the carrier is generated more than a diffusion length away from the junction, then the collection probability of this carrier is quite low. Similarly, if the carrier is generated closer to a region such as a surface with higher recombination than the junction, then the carrier will recombine.
5. ★★Front surface passivation affects carriers generated near the surface, and since blue light is absorbed
very close to the surface, high front surface recombination will affect the \"blue\" portion of the quantum efficiency. Similarly, green light is absorbed in the bulk of a solar cell and a low diffusion length will affect the collection probability from the solar cell bulk and reduce the quantum efficiency in the green portion of the spectrum.
6. ★★(a) A silicon solar cell (bandgap 1.12 eV) is uniformly illuminated by monochromatic light of
wavelength 800 nm and intensity 20 mW/cm2. Given that its quantum efficiency at this wavelength is 0.80, calculate the short circuit current of the cell if its area is 4 cm2.
(b) For the same quantum efficiency, what would be the value of this current if the cell were made from a
30
semiconductor of bandgap (i) 0.7 eV, (ii) 2.0 eV.
(c) For the silicon cell of part (a), calculate the open circuit voltage, fill factor and energy conversion efficiency, given that its ideality factor is 1.2 and dark saturation current density is 1 pA/cm2.
(d) Estimate the range of values of (i) series resistance and (ii) shunt resistance that would cause a relative reduction in the fill factor and energy conversion efficiency of less than 5%.
7. ★★★(a) When the cell temperature is 300 K, a certain silicon cell of 100 cm2 area has an open circuit
voltage of 600 mV and a short circuit current of 3.3 A under 1 kW/m2 illumination. Assuming that the cell behaves ideally, what is its energy conversion efficiency at the maximum power point? (b) What would be its corresponding efficiency if the cell had a series resistance of 0.1 and a shunt resistance of 3?
8. ★★Techniques for reducing the impact of surface recombination.
Since the passivating layer for silicon solar cells is usually an insulator, any region which has an ohmic metal contact cannot be passivated using silicon dioxide. Instead, under the top contacts the effect of the surface recombination can be minimized by increasing the doping. 9. ★
10. ★A schematic of a typical PV-based stand-alone power system
11. ★★7.3 For a location at latitude 34°N, find the angle of solar array tilt that will maximize a system‘s output
for November, using the approximate methods outlined in the text. The average global radiation at this location, on a horizontal surface in November, is 12 MJ/m2/day, and the corresponding figure for diffuse
31
radiation is 4.1 MJ/m2/day.
12. ★★7.4 Design a stand-alone PV system for a location at latitude 23°N. The system is to supply a constant
load of 250 W at 48 VDC. Starting in January, the global figures for radiation on a horizontal surface for the 12 months of the year are (the numbers in parentheses are the corresponding figures for diffuse radiation): 15.5 (3.2), 17.2 (4.2), 21.6 (4.0), 23.3 (6.0), 24.9 (7.0), 24.1 (8.8), 23.8 (8.9), 22.9 (8.1), 20.7 (7.3), 18.9 (4.8), 15.6 (4.7) and 14.5 (3.8) MJ/m2/day, respectively. 1. ★★For a stand-alone PV system for a location at latitude 32.98°N. The system is to supply a constant load of 100 W at 24 VDC , and the required storage 15 days. The average global radiation at this location, on a horizontal surface in July, is 676 mW/cm2/day, and the corresponding figure for diffuse radiation is 214 mW/cm2/day. Answer the following questions: (1) Load determination (2) Select battery capacity (3) First approximation of tilt angle (4) Solar insolation
(5) First approximation of array size
(6) Calculate Ah generated the month, allowing for 10% loss owing to dust coverage. (7) Calculate the monthly load in Ah, allowing for 3% loss due to self-discharge of the battery. (8) Calculate the state of charge of the batteries at the end of the month. (9) Calculate the range of the maximum depth-of-discharge 13. ★★
14. ★
32
15. ★★
16. ★★
Fig. 11.5 Simple DC-to-DC converter. R = resistor, V =voltage source, L=inductor, C=capacitor, Q= transistor, S=control signal, D=diode, Ra=armature resistance, La=armature inductance, E=motor back emf.
四、词组英汉互译题（本大题共10小题，每小题1分，共20分） §0 9. ★★★electromagnetic spectrum 电磁波谱 1. ★solar energy 太阳能 10. ★★★greenhouse effect 温室效应 2. ★applied photovoltaics 应用光伏学 11. ★★★latitude 纬度 §1 12. ★★light intensity 光照强度 1. ★air mass 大气质量 13. ★★★interference effect 干涉效应 2. ★★★atmosphere 大气 14. ★peak sun hours 峰值日照小时数（峰值太阳时） 3. ★★absorption bands 吸收波段 15. ★★★Plank's radiation law 普朗克辐射定律 4. ★★★blackbody radiation 黑体辐射 16. ★★photoelectric effect 光电效应 5. ★★declination of sun 太阳日偏角 17. ★★★photons 光子 6. ★★diffuse radiation 漫射辐射 18. ★photon flux 光子通量 7. ★★direct radiation 直接辐射 19. ★photovoltaic applications 光伏应用 8. ★★★electromagnetic radiation 电磁辐射 20. ★★★quantum mechanics 量子力学
33
21. ★radiant power density 辐射功率密度 22. ★★scattering of light 散射 23. ★★★shading 遮光 24. ★★★spectrum 光谱
25. ★★spectral content 光谱成分
26. ★★★spectral distribution 光谱分布 27. ★spectral irradiance 光谱辐照度
28. ★solar radiation(irradiance) 太阳辐射 29. ★solar insolation 日照
30. ★standard solar spectrum 标准太阳光谱 31. ★★★sunlight 太阳光 32. ★★tilt angle 倾斜角
33. ★★★tilted surfaces 倾斜表面
34. ★typical meteorological year 典型气象年35. ★visible light 可见光 36. ★★★wavelength 波长
37. ★★★wave-particle duality 波粒二象性 §2
1. ★★★absorption 吸收
2. ★absorption coefficient 吸收系数 3. ★absorption depth 吸收深度 4. ★amorphous silicon 非晶硅 5. ★★★bandgap 带隙
6. ★bond model 化学键模型 7. ★band model 能带模型
8. ★★built in potential 内建电势 9. ★★★carrier 载流子
10. ★★conduction band 导带 11. ★★covalent bonds 共价键 12. ★★★crystal lattice 晶格 13. ★crystalline silicon 晶体硅 14. ★★dangling hands 挂键
15. ★dark saturation current 暗饱和电流 16. ★depletion region 耗尽区 17. ★★★diffusion 扩散
18. ★diffusion length 扩散长度 19. ★★★drift 漂移
20. ★★drift transport 漂移传输（输运） 21. ★★★diodes 二极管 22. ★★electric field 电场
23. ★electron-hole pair 电子空穴对 24. ★forward bias 正向偏压 25. ★generation rate 产生率
26. ★★★ideality factor 理想因子
27. ★★ideal diode law 理想二极管定律
28. ★light-induced degradation 光致衰退 29. ★minority carrier lifetime 少子寿命 30. ★★N-type N型(半导体) 31. ★★★recombination 复合 32. ★recombination rate 复合率 33. ★reverse bias 反向偏压
34. ★★★semiconductor 半导体 35. ★★★series 串联
36. ★surface passivation 表面钝化 37. ★P-N junction P-N结 38. ★★P-type P型(半导体)
39. ★photovoltaic effect 光伏效应
40. ★photo(light)-generated carriers 光生载流子 41. ★polycrystalline silicon 多晶硅 42. ★★★potential 势能 43. ★★thin film 薄膜 44. ★★valence band 价带 §3
1. ★★characteristic resistance 特征电阻 2. ★contact resistance 接触电阻 3. ★★concentrator cells 聚光电池 4. ★★collection probability 收集概率
5. ★★current-voltage characteristic 电流电压特性6. ★★★efficiency 效率 7. ★fill factor 填充因子
8. ★light-generated current 光生电流 9. ★★open circuit 开路
10. ★open circuit voltage 开路电压 11. ★parasitic resistance 寄生电阻 12. ★quantum efficiency 量子效率 13. ★series resistance 串联电阻 14. ★★★reflection 反射 15. ★★★resistance 电阻
16. ★★★responsivity 响应度 17. ★series resistance 串联电阻 18. ★★short circuit 短路
19. ★short circuit current 短路电流 20. ★shunt resistance 并联电阻 21. ★spectral response 光谱响应
22. ★★★temperature effect 温度效应 §4
1. ★antireflection coating 减反膜
2. ★★back surface field（BSF） 背电场 3. ★★bulk resistance 体电阻
34
4. ★★★busbars 主栅线 17. ★nominal operating cell temperature (NOCT) 5. ★★★cell thickness 电池厚度 额定电池工作温度 6. ★★★contact resistance losses 接触电阻损失 18. ★packing density 封装密度 7. ★current density 电流密度 19. ★★power dissipation 功率消耗 8. ★★dead layer 死层 20. ★★★thermal resistance 热阻抗 9. ★★★etching 刻蚀 21. ★★★thermal stress 热应力
10. ★★★grid lines 栅线
11. ★★★fingers 副栅线 §6 12. ★high efficiency solar cells 高效率太阳能电池 1. ★★alternating current 交变电流 13. ★laser grooved, buried contact solar cells 2. ★★★alkaline manganese batterie 碱性锰电池
激光刻槽，埋栅太阳能电池 3. ★★★batteries 电池，蓄电池 14. ★light trapping 光陷阱 4. ★★★battery housing 电池安置 15. ★★★losses 损耗 5. ★★★cable 电缆，布线 16. ★optical losses 光学损失 6. ★charge controllers 充电控制器 17. ★★production lines 生产线 7. ★charge regulator 充电稳压器 18. ★★★pyramids 金字塔(结构) 8. ★constant voltage regulation 恒压调节 19. ★★rear contact solar cells 背电极太阳能电池 9. ★★concentrator arrays 聚光发电阵列 20. ★★rear surface reflection 背面反射 10. ★★coulombic efficiency 库仑效率 21. ★recombination losses 复合损失 11. ★backup generator 备用发电机 22. ★★refractive index 折射率 12. ★battery efficiency 蓄电池效率 23. ★★★resistivity 电阻率 13. ★battery capacity 蓄电池容量 24. ★★resistive losses 电阻损耗 14. ★★battery charging 蓄电池充电 25. ★screen printed cells 丝网印刷电池 15. ★★connectors 连接器 26. ★★shading losses 遮光损失 16. ★depth-of-discharge 放电深度 27. ★★sheet resistivity 方块(薄层)电阻率 17. ★★direct drive applications 直接驱动应用 28. ★★spacing 间距 18. ★★discharge rate 放电速率 29. ★★surface texturing 表面织构 19. ★DC-to-DC converter 直流-直流转换器 30. ★top contact 顶电极 20. ★★★earthing (grounding) 接地 21. ★★electricity grid 电力网络 §5 22. ★★★electrolyte agitation 电解液搅拌 1. blocking diode 阻塞二极管 23. ★★electronics 电子器件 2. bypass diodes 旁路二极管 24. ★★energy efficiency 能量使用效率 3. cell degradation 电池老化 25. ★★energy storage 能量存储 4. circuit design 电路设计 26. ★★fixed arrays 固定阵列 5. commercial modules 商用组件 27. ★★★fuses 保险丝 6. corrosion 腐蚀 28. ★★freeze protection 冻结防护 7. delamination 脱层 29. ★grid-connected systems 并网系统 8. encapsulant failure 封装失效 30. ★★high voltage disconnect 高压断路 9. environmental protection 抗候性，耐候性 31. ★★★hysteresis 滞后(电压) 10. load 负载 32. ★★interrupting(on/off) regulation 中断(开11. hot spots 热斑 关)调节 12. insulation 绝缘 33. ★★★inverter 逆变器 13. interconnects 互联 34. ★induction motors 感应电动机 14. interconnect-busbars 互联主栅线 35. ★isolation transformers 绝缘变压器 15. mismatch losses 错配损失 36. ★lead-acid batteries 铅酸蓄电池 16. modules 组件 37. ★life expectancy 寿命期望
35
38. ★★lightning protection 避雷 39. ★★★lithium batteries 锂电池
40. ★★★low voltage disconnect 低压断路
41. ★maximum power point tracker 最大功率点
42. ★★module mounting 组件支架 43. ★★motor starting 电动机启动 44. ★★★navigational aids 航海协助 45. ★nickel-cadmium batteries 镍镉电池
46. ★★★nickel-metal-hydride batteries 镍氢电池 47. ★★over-current protection 过流保护 48. ★power conditioning 功率调节 49. ★power rating 额定功率
50. ★★pulse width modulation 脉宽调制 51. ★★redox-flow batteries 氧化还原蓄电池 52. ★★★regulators 稳压器，调节器 53. ★remote areas 偏远地区 . ★self-discharge 漏电
55. ★self-regulating systems 自我调制系统 56. ★★series regulators 串联调节器 57. ★★shunt regulators 并联调节器
58. ★shunt resistance 并联电阻，分流电阻，旁
路电阻
59. ★★★signage 标识 60. ★★sine wave 正弦波
61. ★★★square wave inverters 方波逆变器 62. ★standby power loss(draw) 待机能耗 63. ★stand-alone systems 系统 . ★state of charge 充电状态 65. ★★★subsidies 补贴 66. ★★★sulphation 硫酸化
67. ★★super capacitors 超级电容器 68. ★★★switches 开关
69. ★★system components 系统组成部分 70. ★system design 系统设计
71. ★★temperature sensitivity 温度敏感度 72. ★★★tracking 跟踪 73. ★★★ventilation 通风
74. ★voltage efficiency 电压效率
75. ★voltage regulator 电压调整器，稳压器
§7
1. ★charging efficiency 充电效率 2. ★★electrical loads 电力负载 3. ★★peak watts 峰瓦 4. ★★load profile 负载型态
36
5. ★★loss-of-load probability 负载流失概率 6. ★hybrid system 混合系统
7. ★★microwave repeater station 微波中继站 8. ★★★modularity 模块性
9. ★★resource assessment 资源评估 10. ★★★simulation 模拟
11. ★system availability 系统利用率 §8
1. ★★★airships 飞空艇 2. ★★anode 阳极，正极
3. ★battery charger 蓄电池充电器 4. ★cathodic protection 阴极保护 5. ★charging efficiency 充电效率 6. ★consumer education 消费者教育 7. ★★consumer products 消费品 8. ★★★controllers 控制器
9. ★★current controller 电流控制器 10. ★DC-DC conversion 直流-直流转换 11. ★★deep cycle battery 深循环电池 12. ★★electric motors 电动机 13. ★★electric fences 电栅栏
14. ★★★electrochemical potenitial 电化学势 15. ★★gallium arsenide 砷化稼
16. ★★★integrity factors 完整性因子 17. ★★★lighting 照明
18. ★★★mobile phone 移动电话 19. ★★★monitoring 监控
20. ★monitoring systems 监控系统 21. ★★★noise barriers 噪音屏障 22. ★★★optical fiber 光导纤维 23. ★★pole mounted 杆端安装 24. ★★pumping head 泵扬程
25. ★★★radiation hardness 辐射硬度 26. ★★★radio telephone 无线电电话 27. ★★★refrigeration 冷藏 28. ★★remote monitoring 远程监测 29. ★★repeater stations 中继站 30. ★★replenishment rate 补给率 31. ★★space applications 空间应用 32. ★solar cars 太阳能汽车
33. ★★solar-powered aircraft 太阳能飞行器 34. ★★system sizing 系统规模制定 35. ★★★telecommunications 电信
36. ★★transportable solar power supply 可运
输式太阳能电力供应
37. ★water pumping 抽水 38. ★wiring losses 配线损耗 §9
1. ★AC power 交流电
2. ★★assistance schemes 援助计划
3. ★charging/discharging rates 充电/放电速率 4. ★★diesel generator 柴油发电机 5. ★★fluorescent lights 荧光灯
6. ★household power systems 家用电力系统 7. ★hybrid systems 混合系统 8. ★inverter losses 逆变器损失 9. ★★passive solar 被动太阳能 10. ★★petrol generator 汽油发电机 11. ★portable systems 便携式系统 12. ★peak load 峰值负载
13. ★★reliability and maintenance 可靠性和维护 14. ★remote area power supply (RAPS) systems 偏
远地区供电系统
15. ★solar water heater 太阳能热水器 §10
1. ★building-integrated PV (BIPV) 光伏建筑一
体化
2. ★semiconductor switches 半导体开关 3. ★★capacity factor 产能要素 4. ★★capacity credit 产能信用度 5. ★★capacity value 产能值
6. ★cell interconnection 电池互联
7. ★distrbution network 电力供应网络 8. ★circuit breakers 断路器
9. ★distributed photovoltaic systems 分布式光
伏系统
10. ★distributed utility concept 分布式供电概念 11. ★load management 负载管理 12. ★★power factor 功率因数 13. ★★★islanding 孤岛效应
14. ★★value of PV generated power 光伏发电的
价值
15. ★★integral mount 集成安装
16. ★★★economic viability 经济可行性 17. ★★★experience curve 经验曲线 18. ★★★venting 排风、通风
19. ★renewable energy 可再生能源 20. ★Thermal overload 热负载
21. ★life expectancy 寿命期望，平均寿命 22. ★★line losses 输电线能量损耗 23. ★net metering 双向电表 24. ★★★externality 外在性
25. ★★rooftop systems 屋顶系统 26. ★★summer peaking 夏季峰值
27. ★★★rural electrification 乡村电气化 28. ★★★harmonic content 谐波成分 29. ★★demand-side management 需求方管理 30. ★array arcing 阵列电弧
31. ★★rack mounts 支架固定器 §11
1. ★★★pumps 泵
2. ★series DC motor 串联直流电动机 3. ★★law starting torque 低启动扭矩 4. ★★armature resistance 电枢电阻
5. ★★sealed batteries 封装电池，密封电池 6. ★AC motors 交流电动机 7. ★centrifugal pumps 离心泵 8. ★★starting torque 启动扭矩
9. ★★submersible pumps 潜水式泵 10. ★★submersible mortar 潜水式电动机 11. ★volumetric pump 容积泵
12. ★manual tracking system 手动跟踪系统 13. ★★reciprocating piston pump 往复式活塞泵 14. ★★array mounting 阵列固定 15. ★DC shunt motor 直流并励电动机 16. ★DC motor 直流电动机
17. ★★self-priming centrifugal pumps 自吸离心泵
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