TWI556570B - Measuring device for property of solar cell and measuring method using the same - Google Patents

Description

Solar cell characteristic measuring device and measuring method using same

The present invention relates to a measuring device for solar cell characteristics and a measuring method using the same, and in particular to a measuring device for solar cell characteristics and a measuring method using the same.

Solar cells convert light energy into electrical energy. Before using a solar cell, it is necessary to understand the characteristics of the solar cell to provide an appropriate electrical signal to the solar cell to obtain a corresponding illuminance and/or illuminating color temperature. Therefore, how to accurately obtain the characteristic curve of the solar cell is one of the efforts of the industry.

Therefore, the present invention provides a measuring device and a measuring method using the same, which can obtain an accurate solar cell characteristic curve.

According to an embodiment of the invention, a measuring device is proposed. The measuring device is used to measure the characteristics of a solar cell. The measuring device comprises a plurality of light sources, a feedback control module and a power measuring unit. The color lights of the respective light sources are different, and each light source includes a plurality of symmetrical light emitting elements. Feedback control module to control these hair An illuminance of light emitted by an optical component. The feedback control module is configured to determine whether the instability of the illumination is less than a first preset ratio. If the instability of the illuminance is less than the first predetermined ratio, the power supply measuring unit measures the characteristics of the solar battery under the illuminance.

According to another embodiment of the present invention, a measurement method is proposed. The measurement method is used to measure the characteristics of a solar cell. The measurement method includes the following steps. A measuring device is provided, wherein the measuring device comprises a plurality of light sources, a feedback control module and a power measuring unit. The feedback control module controls an illuminance of the light in a feedback control manner; determines whether the illuminance instability is less than a first preset ratio; and if the illuminance instability is less than the first preset ratio, The characteristics of the solar cell are measured under illumination.

In order to better understand the above and other aspects of the present invention, the preferred embodiments are described below, and in conjunction with the drawings, the detailed description is as follows:

10‧‧‧ solar cells

100‧‧‧Measurement device

110‧‧‧Receipt Department

120‧‧‧ lamp holder

120b‧‧‧lower surface

130, 140‧‧‧ light source

131‧‧‧First light source

1311‧‧‧Lighting elements

132‧‧‧second light source

133‧‧‧ Third light source

134‧‧‧fourth light source

135‧‧‧ fifth light source

136‧‧‧ sixth light source

150‧‧‧ Carrier Board

150u‧‧‧ upper surface

160‧‧‧Feedback control module

161‧‧‧Light sensor

162‧‧‧Responsible controller

163‧‧‧ illuminance uniformity calculator

170‧‧‧Power Measurement Unit

a, b, c, d, e, f‧‧ points

C1, C2, C3, C4‧‧‧ curves

C5, C6‧‧‧ linear equation

e(t)‧‧‧ error signal

FF‧‧‧fill factor

Isc‧‧‧Short-circuit current

L1‧‧‧Light

M ₀ ‧‧‧ initial illuminance

M _a ‧ ‧ illuminance average

M _av ‧‧‧ illuminance unevenness

M _max ‧‧‧maximum illumination value

M _min ‧‧‧ minimum illumination value

M _t ‧‧‧illuminance instability

r(t)‧‧‧ initial value

R1‧‧‧ area

S1‧‧‧closed space

S110 to S150‧‧‧ steps

S _d ‧‧‧ illuminance standard deviation

t ₀ , t ₁ , t ₂ ‧‧‧ points

△ t ‧‧‧ time interval

u(t)‧‧‧ Input signal

FIG. 1 is a flow chart showing a measurement method according to an embodiment of the invention.

2 is a schematic view of a measuring device according to an embodiment of the invention.

Figure 3 is a bottom view of the lamp holder and the light source of Figure 2.

Figure 4A is a schematic view showing the use of the measuring device of Figure 2 to define an area.

FIG. 4B is a top view of the measuring device of FIG. 4A (the lamp holder and the light source are not shown).

FIG. 5A is a schematic diagram showing the illumination of the light source controlled by the measuring device of FIG. 2.

FIG. 5B is a top view of the measuring device of FIG. 5A (the lamp holder and the light source are not shown).

Figure 6 is a block diagram showing the function of the feedback controller of Figure 2.

Figure 7 is a graph showing changes in illuminance of light emitted by the light source of Figure 5A.

Fig. 8 is a graph showing the relationship between the voltage and current of the solar cell of Fig. 5A.

Fig. 9 is a graph showing the relationship between the illuminance and the short-circuit current of the solar cell of Fig. 5A.

Figure 10 is a graph showing the relationship between the temperature and the fill factor of the solar cell of Figure 5A.

FIG. 1 is a flow chart showing a measurement method according to an embodiment of the invention.

In step S110, the measuring device 100 is provided.

Please refer to FIGS. 2 and 3 . FIG. 2 is a schematic diagram of a measuring device 100 according to an embodiment of the invention. FIG. 3 is a bottom view of the lamp holder 120 and the light source 130 of FIG. 2 . The measuring device 100 includes a receiving portion 110, a socket 120, a plurality of light sources 130, a light source 140, a carrier 150, a feedback control module 160, and a power measuring unit 170.

The measuring device 100 is used to measure the characteristics of the solar cell 10. The solar cell 10 is provided on the upper surface 150u of the carrier 150. The solar cell 10 is electrically connected to the power measuring unit 170. The source measuring unit (SMU) 170 can calculate various characteristics of the solar cell 10 according to the electrical signals of the solar cell 10, such as voltage and current characteristic curves, illuminance and short circuit. Current characteristic curve, Temperature and fill factor (FF) characteristics or other characteristics.

The accommodating portion 110 is disposed between the socket 120 and the carrier 150. The accommodating portion 110, the lamp holder 120 and the carrier 150 form a closed space S1. The light source 130 can be disposed in the closed space S1 to reduce or even avoid the amount of light leakage from the light source 130. In one embodiment, the receiving portion 110 can be in a closed loop shape, and the cross section can be circular, polygonal or other shape.

The lamp holder 120 can be controlled by the feedback control module 160 so that the light source 130 disposed on the lamp holder 120 can be controlled by the feedback control module 160.

The light source 130 is disposed on the lower surface 120b of the socket 120. Each light source 130 may be a standard light source for indoor or outdoor lighting, such as ISO/CIE 8995-1, North American Lighting Association IESNA, British BS EN 12464-1, German prEN 12464-1, Japan JIS Z0125. -2007, Singapore SS531-2006, Australia AS/NZS 1680-2006, US ASHARE90.1-2007 and other light sources. Specifically, each light source 130 may be a D65 light source (simulating blue sky daylight) with a color temperature of 6500K, a D75 light source with a color temperature of 7500K (which can simulate the northern average sunlight), a D50 light source with a color temperature of 5000K (which can simulate natural sunlight), and a color temperature. 4000K TL84 light source (can simulate European store lighting), D65 light source with color temperature 4100K (simulating blue sky daylight), CWF light source with color temperature of 6500K (can simulate American store lighting), U30 light source with color temperature 3000K (can simulate another American store lighting) ), U35 light source with color temperature of 3500K (can simulate the designated store lighting), F light source with color temperature of 2700K (can simulate the warm light of family hotel) or white light (Incandescent) light source with color temperature of 2856K (can simulate the projection lamp of the exhibition hall).

Each of the light sources 130 can emit visible light of different color temperatures, for example, visible light that can emit a color temperature between 2700K and 7500K, but can also be other color light ranges. In addition, another light source 140 is disposed at a central position of the socket 120, which emits invisible light, such as an ultraviolet light source.

Light source 130 can be a point source or a line source. At least one of the plurality of light sources 130 may be a point source, and the others may be line sources. For example, the light source 130 may include a first light source 131, a second light source 132, a third light source 133, a fourth light source 134, a fifth light source 135, and a sixth light source 136, wherein the first light source 131, the second light source 132, and the third light source 133. The fourth light source 134, the fifth light source 135, and the sixth light source 136 may be point light sources, and the third light source 133 and the sixth light source 136 may be point light sources.

In addition, each light source 130 includes a plurality of symmetrical light emitting elements. For example, the first light source 131 includes a plurality of symmetrically arranged light-emitting elements 1311 that are symmetrically disposed with respect to a central position of the socket 120. Since a plurality of light-emitting elements of the respective light sources 130 are symmetrically arranged, overall illumination uniformity can be increased.

The feedback control module 160 includes a photo sensor 161, a feedback controller 162, and an illuminance uniformity calculator 163. The photo sensor 161 can be disposed in the enclosed space S1 and can detect the emission of the light emitting element of the light source 130. The illuminance of the light ray L1, the feedback controller 162 can control at least one of the plurality of light sources 130 to emit light, and the illuminance uniformity calculator 163 can define the uniformity of illumination according to the illuminance detection signal of the light sensor 161. An area. The feedback controller 162 can control the illumination stability. In addition, the feedback controller 162 and/or the illuminance uniformity calculator 163 may be half Conductor circuits, software and/or firmware, both of which can be integrated or individually configured. In addition, the feedback controller 162 and the illuminance uniformity calculator 163 can be provided on a desktop computer, a server, a notebook computer, or other types of electronic devices.

In step S120, the illuminance uniformity calculator 163 may define a region R1 in which the illuminance unevenness of the light ray L1 emitted by the illuminating element of the light source 130 is smaller than the second preset ratio, wherein the second preset ratio is, for example, 1% or other. The appropriate ratio value.

For example, please refer to FIG. 4A and FIG. 4B, FIG. 4A is a schematic diagram showing the region R1 defined by the measuring device 100 of FIG. 2, and FIG. 4B is a top view of the measuring device 100 of FIG. 4A (not shown) The lamp holder 120 and the light source 130). The plurality of photo sensors 161 may be arranged in an array on the upper surface 150u of the carrier 150, and the photo sensors 161 may be electrically connected to the illuminance uniformity calculator 163. Then, each photo sensor 161 transmits the detected illuminance detection signal of the light L1 to the illuminance uniformity calculator 163. The illuminance uniformity calculator 163 calculates the range of the region R1 in which the illuminance unevenness M _{av is} smaller than the second preset ratio according to the illuminance detection signals of the photo sensors 161 .

The calculation formula of the illuminance unevenness M _av of the present embodiment is as follows (1). In the formula (1), M _max represents the maximum illuminance value in the region R1, and M _min represents the minimum illuminance value in the region R1.

In step S130, the illuminance of the light L1 emitted by the light source 130 can be controlled in a manner of feedback control, so that the illuminance stability is less than a first preset ratio. For example, to increase the accuracy of the solar cell characteristics measured by the measuring device 100. The "accuracy" herein means that the solar cell characteristic curve measured by the measuring device 100 of the embodiment of the present invention can accurately reflect the inherent characteristics of the solar cell 10 itself. Further explanation below.

Please refer to FIG. 5A and FIG. 5B , FIG. 5A is a schematic diagram showing the illumination of the light source 130 by using the measuring device 100 of FIG. 2 , and FIG. 5B is a top view of the measuring device 100 of FIG. 5A ( the light is not shown) Seat 120 and light source 130). In this step, the solar cell 10 and the photo sensor 161 can be disposed in the region R1. Since the illuminance unevenness M _{av of the} region R1 is smaller than the second predetermined ratio, the accuracy with which the power supply measuring unit 170 measures the characteristics of the solar cell 10 can be increased.

FIG. 6 is a functional block diagram of the feedback controller 162 of FIG. 2. The feedback controller 162 controls the illumination instability of the light L1 emitted by the light-emitting elements to be less than a first predetermined ratio in a manner of feedback control to increase the accuracy of the power measurement unit 170 for measuring the characteristics of the solar battery 10. Degree, wherein the first predetermined ratio is, for example, 1% or other suitable ratio value.

In this embodiment, the feedback controller 162 is, for example, a proportional-integral-differential (PID) controller, which is composed of a proportional unit, an integral unit, and a differential unit, which respectively pass Kp, Ki, and Kd. Parameter settings. In this embodiment, the feedback controller 162 is a 5-parameter PID controller. For example, the parameters of the feedback controller 162 include Td and Ti parameters in addition to the above three parameters Kp, Ki and Kd, wherein the parameter Td is equal to Kd/Kp (the quotient or ratio of Kd and Kp), and the parameter Ti is equal to Kp. /Ki (the quotient or ratio of Kd to Ki). Feedback control of Figure 6 The 162 can output a signal u(t) to control the illuminance of the light source 130. The relationship between the output signal u(t) and the error signal e(t) and the 5 parameter is as follows (2).

Due to the design of the 5-parameter, the illuminance instability of the light ray L1 can be reduced, so that the sensing error of the photo sensor 161 can be compensated. Further, in general, the photo sensor 161 has a certain sensing error. The smaller the sensing error, the more complicated the circuit design and the higher the cost; otherwise, the circuit design is simpler and the cost is lower. Since the measuring device 100 of the embodiment of the present invention controls the illuminance instability to a predetermined ratio through the feedback control, even if the photo sensor 161 having a large amount of sensing error is used, the measured solar energy can be obtained. The accuracy of the characteristics of the battery 10 is maintained within a tolerance range.

FIG. 7 is a diagram showing changes in illuminance of light emitted by the light source 130 of FIG. 5A. The curve CI represents the tendency of the illuminance of the ray L1 to change with time. At the time point t ₀ , the initial value of the input feedback controller 162 is r(t), so that the light source 130 emits the light ray L1 whose initial illuminance is M ₀ . Since the feedback controller 162 continuously receives the illumination detection signal of the photo sensor 161, the control mode can be fed back, and the illumination of the light L1 is controlled to develop in a more stable direction according to the latest illumination detection signal. For example, the illumination of the light ray L1 is gradually stabilized from the time point t ₀ to the time point t ₁ by the feedback control method. In one embodiment, the period from time point t ₀ to time point t ₁ is about 20 minutes to 30 minutes. Under the feedback control, the illuminance instability M _t after the time point t _{1 is} smaller than the first preset ratio, so that the accuracy of the power measurement unit 170 to measure the characteristics of the solar cell 10 can be increased.

The calculation formula of the illuminance instability M _t of the present embodiment is as follows (3). In the formula (3), S _d represents the standard illumination region R1 of a time interval difference (Standard Deviation), and M _a represents the average value of illuminance in the time interval region R1. For example, the time point t2 illumination instability M _t is the quotient of the standard illuminance and the illuminance difference between the average value S _d M _a in the time interval △ t, where △ t time interval, for example, farther back from the time point t2 period Time, which can be ten minutes or any time interval.

In addition, since the measuring device 100 of the embodiment of the present invention automatically adjusts the illuminance of the light L1 emitted by the light source 130 by using the feedback control mode, it is not necessary to manually adjust the illuminance of the light source, and it is not necessary to adjust the distance between the solar cell 10 and the light source 130. Way to adjust the illumination.

In step S140, the feedback controller 162 determines whether the illuminance instability M _t is less than the first preset ratio, and if so, proceeds to step S150; if not, returns to step S130 until the illuminance instability M _{t is} controlled to be less than a preset ratio.

In step S150, the power supply measuring unit 170 measures the characteristics of the solar cell 10, such as a voltage-current relationship curve, an illuminance and a short-circuit current relationship curve, and/or temperature, when the illuminance instability _{Mt is} less than the first predetermined ratio. Curve with the fill factor.

Fig. 8 is a graph showing the relationship between voltage and current of the solar cell 10 of Fig. 5A. Curve C2 is measured using the measuring device 100 of FIG. 5A A characteristic curve of the voltage and current of the solar cell 10 is measured. Due to the design of the measuring device 100 of the embodiment of the present invention, the illuminance instability of the light ray L1 is less than the first preset ratio and/or the illuminance unevenness is less than the second preset ratio, so at different times (or different measurements) The trend of several curves measured by the batch is roughly the same or overlap, as curve C2. In contrast, if the illuminance instability of the light ray L1 is greater than the first preset ratio and/or the illuminance non-uniformity change is greater than the first preset ratio, the plurality of curves measured at different times will be inconsistent, such as a time. The point is measured by the curve C3, while the other time point is measured by the different curve C4.

Fig. 9 is a graph showing the relationship between the illuminance of the solar cell 10 of Fig. 5A and the short-circuit current Isc. Points a, b, and c in Fig. 9 measure the characteristic points of the solar cell 10 using the measuring device 100 of Fig. 5A. Points a, b, and c indicate the tendency of the short-circuit current Isc of the solar cell 10 to vary with illumination at the same temperature of the solar cell 10. The short-circuit current Isc at each point is different under different illumination levels. For example, in the case of point a, the short-circuit current of solar cell 10 is about 0.08 milliamperes (mA) under illumination of light illuminance Llux of 50 lux; at point b, the illumination is 200 lux. Under the irradiation of the light beam L1, the short-circuit current of the solar cell 10 is about 0.21 mA; at point c, the short-circuit current of the solar cell 10 is about 0.83 mA under the irradiation of the light L1 having an illuminance of 1000 lux. By the mathematical method of fitting the curve by polynomial, the linear equation C5 of points a, b and c can be obtained, and the linear equation C5 can be regarded as the illuminance and short-circuit current characteristic curve of the solar cell 10.

In another embodiment, the carrier 150 of FIG. 5A may be a temperature control panel. For example, the carrier 150 has a heater and a cooler, which are permeable to heat and/or cold. However, the temperature of the solar cell 10 is controlled. Since the carrier 150 can control the temperature of the solar cell 10 to be maintained at a temperature value or to another temperature value.

A characteristic curve of the temperature and the filling factor of the solar cell 10 can be obtained by temperature control of the carrier 150, which will be further described below with reference to FIG.

Fig. 10 is a graph showing the relationship between the temperature and the filling factor of the solar cell 10 of Fig. 5A. Points d, e, and f of Fig. 10 are used to measure the characteristic points of the solar cell 10 using the measuring device 100 of Fig. 5A. Points d, e, and f represent the same type of light source 130 and the filling factor FF of the solar cell 10 changes with temperature under the same illuminance. At different temperatures, the fill factor FF of each point is different. For example, in the case of point d, when the temperature of the solar cell 10 is 15 degrees Celsius, the filling factor of the solar cell 10 is about 44.5%; at the point e, when the temperature of the solar cell 10 is 26 degrees Celsius, the solar energy The fill factor of the battery 10 is about 45.7%; at point f, the fill factor of the solar cell 10 is about 46.2% at a temperature of the solar cell 10 of 35 degrees Celsius. A linear equation C6 of points d, e, and f can be obtained by a mathematical method of fitting a curve by a polynomial, and the linear equation C6 can be regarded as a temperature and fill factor characteristic curve of the solar cell 10.

During the execution of step S150, the feedback controller 162 still uses the feedback control method to continuously control the illuminance instability Mt within the first predetermined ratio to maintain the accuracy of the measured solar cell 10 characteristics. degree.

In summary, since the measuring device of the embodiment of the present invention automatically controls the illuminance of the light emitted by the light source by using the feedback control method, it is not necessary to manually adjust the illuminance of the light source, and it is not necessary to adjust the distance between the light source and the solar battery. Illuminance, and the accuracy of the obtained solar cell characteristics can be improved.

In conclusion, the present invention has been disclosed in the above preferred embodiments, and is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

10‧‧‧ solar cells

100‧‧‧Measurement device

110‧‧‧Receipt Department

120‧‧‧ lamp holder

120b‧‧‧lower surface

130‧‧‧Light source

150‧‧‧ Carrier Board

150u‧‧‧ upper surface

160‧‧‧Feedback control module

161‧‧‧Light sensor

162‧‧‧Responsible controller

163‧‧‧ illuminance uniformity calculator

170‧‧‧Power Measurement Unit

Claims (16)

A measuring device for measuring characteristics of a solar cell, the measuring device comprising: a plurality of light sources, each of the light sources having different color light systems, and each of the light sources comprises a plurality of symmetrically arranged light emitting elements; a feedback control module for controlling an illuminance of one of the light emitted by the illuminating elements and determining whether the illuminance instability is less than a first predetermined ratio; and a power measuring unit, if the illuminance is not The stability is less than the first predetermined ratio, and the power measuring unit measures the characteristics of the solar cell under the illumination. The measuring device according to claim 1, wherein the first preset ratio is 1%. The measuring device of claim 1, wherein the feedback control module comprises: a feedback controller; and a light sensor for detecting the illumination of the light. The measuring device of claim 3, wherein the feedback controller is a proportional-integral-derivative (PID) controller. The measuring device according to claim 4, wherein the PID control The number of parameters of the controller is five. The measuring device of claim 1, wherein the solar cell is located in an area below the light source, and an unevenness of the illuminance in the area is less than a second predetermined ratio. The measuring device of claim 6, wherein the second predetermined ratio is 1%. The measuring device of claim 1, further comprising: a lamp holder, wherein the light sources are disposed on the lamp holder; a carrier plate for carrying the solar cell; and a receiving portion located at the The lamp holder is disposed between the lamp holder and the carrier plate for receiving the light source and the solar cell. The measuring device of claim 8, wherein the carrier is a temperature control panel. A measuring method for measuring characteristics of a solar cell, the measuring method comprising: providing a measuring device as described in claim 1 of the patent application; the feedback control module is in a feedback control manner, Controlling the light-emitting elements Shooting an illumination of a light; the feedback control module determines whether the instability of the illumination is less than a first preset ratio; and if the instability of the illumination is less than the first preset ratio, the power measurement The unit measures the characteristics of the solar cell under the illumination. The measuring method according to claim 10, wherein the first preset ratio is 1%. The measuring method of claim 10, further comprising: defining an area in which the unevenness of the illuminance is less than a second predetermined ratio; wherein, in the step of measuring characteristics of the solar cell, The solar cell is located in this area. The measuring method according to claim 12, wherein the second preset ratio is 1%. The measurement method of claim 10, wherein the feedback control module comprises: a feedback controller; and a light sensor for detecting the illumination of the light. The measuring method of claim 14, wherein the feedback controller is a PID controller. The measuring method according to claim 15, wherein the number of parameters of the PID controller is five.