阅读说明：本技术 太阳能发电系统及检测方法 (Solar power generation system and detection method ) 是由 李雷鸣 林信晃 于 2020-05-08 设计创作，主要内容包括：本公开内容关于一种太阳能发电系统及检测方法,其中检测方法用以对太阳能发电系统进行检测。太阳能发电系统包含太阳能板以及直交流转换器,当直交流转换器处于发电模式时,太阳能板产生的光电电能经过直交流转换器传送至外部电网。检测方法包含：当直交流转换器进入与发电模式相异的检测模式时,控制直交流转换器由外部电网汲取电能,产生检测电能传送至太阳能板,使太阳能板在检测电能通过的情况下由检测仪器得到太阳能板的检测结果。(The disclosure relates to a solar power generation system and a detection method, wherein the detection method is used for detecting the solar power generation system. The solar power generation system comprises a solar panel and an AC-DC converter, and when the AC-DC converter is in a power generation mode, photoelectric electric energy generated by the solar panel is transmitted to an external power grid through the AC-DC converter. The detection method comprises the following steps: when the direct-current/alternating-current converter enters a detection mode different from the power generation mode, the direct-current/alternating-current converter is controlled to draw electric energy from an external power grid, detection electric energy is generated and transmitted to the solar panel, and the solar panel obtains a detection result of the solar panel through a detection instrument under the condition that the detection electric energy passes through the solar panel.)

1. A detection method is used for detecting a solar power generation system, the solar power generation system comprises a solar panel and a direct current-alternating current converter, when the direct current-alternating current converter is in a power generation mode, photoelectric electric energy generated by the solar panel is transmitted to an external power grid through the direct current-alternating current converter, and the detection method comprises the following steps:

when the DC-AC converter enters a detection mode different from the power generation mode, the DC-AC converter is controlled to draw electric energy from the external power grid, and detection electric energy is generated and transmitted to the solar panel, so that the solar panel obtains the detection result of the solar panel through a detection instrument under the condition that the detection electric energy passes through.

2. The method of claim 1, wherein the solar power generation system further comprises a DC converter and a bypass switch circuit, the DC converter is coupled between the solar panel and the DC converter, the solar panel generates a first DC voltage in the power generation mode, the first DC voltage is converted into a second DC voltage by the DC converter, the second DC voltage is converted into an output AC voltage by the DC converter and transmitted to the external power grid, the bypass switch circuit is connected in parallel with the DC converter and coupled between the solar panel and the DC converter, the method comprises:

and under the detection mode, the bypass switch circuit is controlled to be conducted, so that the detection electric energy is transmitted to the solar panel from the direct current-alternating current converter through the bypass switch circuit.

3. The detection method of claim 2, wherein when the solar power generation system enters the detection mode from the power generation mode, the detection method comprises:

controlling the bypass switch circuit to switch from an off state to an on state; and

and controlling the DC-AC converter to draw electric energy from the external power grid to generate the detection electric energy.

4. The detection method of claim 2, wherein when the solar power generation system ends the detection mode and returns to the power generation mode, the detection method comprises:

controlling the DC-AC converter to stop generating the detection electric energy;

detecting a voltage difference between the DC-AC converter and the solar panel; and

and controlling the bypass switch circuit to be switched from the on state to the off state.

5. The detection method of claim 1, wherein the solar power generation system further comprises an energy storage capacitor coupled between the solar panel and the DC-to-AC converter, and the energy storage capacitor and the DC-to-AC converter cooperate to provide the detection power to the solar panel in the detection mode.

6. The detection method of claim 1, wherein the detection method further comprises:

and detecting the magnitude of the detection electric energy flowing into the solar panel in the detection mode.

7. The detection method of claim 1, wherein the detection method further comprises:

in the detection mode, a thermal imaging instrument or a spectrum analyzer is used for shooting a detection image of the solar panel with the inflow of the detection electric energy; and

the detection image is analyzed to judge whether the solar panel is normal or damaged.

8. The detection method of claim 1, wherein the detection method further comprises:

receiving a detection current value returned by a current sensor;

comparing the detected current value with a set current value;

and controlling the DC-AC converter according to the comparison result to adjust the voltage level or the current of the detected electric energy.

9. A solar power generation system, comprising:

a DC/AC converter coupled between an external power grid and a solar panel; and

the control unit is coupled with the DC-AC converter and is used for controlling the DC-AC converter to switch between a power generation mode and a detection mode;

when the direct current-alternating current converter is in the power generation mode, photoelectric electric energy generated by the solar panel is converted and transmitted to an external power grid through the direct current-alternating current converter;

when the DC-AC converter is in the detection mode, the control unit controls the DC-AC converter to draw electric energy from the external power grid and generate detection electric energy to be transmitted to the solar panel, so that the solar panel obtains the detection result of the solar panel by a detection instrument under the condition that the detection electric energy passes through.

10. The solar power generation system of claim 9, wherein the solar power generation system further comprises:

the direct current converter is coupled between the solar panel and the direct current-alternating current converter, the solar panel generates a first direct current voltage in the power generation mode, the first direct current voltage is converted into a second direct current voltage through the direct current converter, and the second direct current voltage is converted into an output alternating current voltage through the direct current-alternating current converter and is transmitted to the external power grid.

11. The solar power generation system of claim 10, wherein the solar power generation system further comprises:

a bypass switch circuit connected in parallel with the DC converter and coupled between the solar panel and the DC-AC converter, the control unit coupled to the bypass switch circuit,

in the detection mode, the control unit controls the bypass switch circuit to be conducted, so that the detection electric energy is transmitted to the solar panel from the direct current-alternating current converter through the bypass switch circuit.

12. The solar power generation system of claim 11, wherein the dc converter comprises a diode connected in parallel with the bypass switch circuit and configured to transmit a detection current from the solar panel to the dc-to-ac converter.

13. The solar power generation system of claim 12, wherein the dc converter further comprises an inductor, the bypass switch circuit being connected in parallel with the diode and the inductor of the dc converter.

14. The solar power generation system of claim 11, wherein the control unit controls the bypass switch circuit to switch from an off state to an on state when the solar power generation system enters the detection mode from the power generation mode; and the control unit controls the DC-AC converter to draw electric energy from the external power grid to generate the detection electric energy.

15. The solar power generation system of claim 11, wherein when the solar power generation system ends the detection mode and returns to the power generation mode, the control unit controls the dc-ac converter to stop generating the detection power; the control unit detects the voltage difference between the DC-AC converter and the solar panel; and the control unit controls the bypass switch circuit to be switched from a conducting state to a switching-off state.

16. The solar power generation system of claim 9, wherein the solar power generation system further comprises an energy storage capacitor coupled between the solar panel and the dc-to-ac converter, the energy storage capacitor and the dc-to-ac converter cooperating in the detection mode to provide the detection power to the solar panel.

17. The solar power generation system of claim 10, wherein the dc converter is a unidirectional dc converter configured to generate the second dc voltage as an output to the dc-to-ac converter according to the first dc voltage of the solar panel as an input.

18. The solar power generation system of claim 9, wherein the solar power generation system further comprises:

and the current sensor is used for detecting the magnitude of the detection electric energy flowing into the solar panel in the detection mode.

19. The solar power system of claim 9, wherein the dc-to-ac converter is a bi-directional dc-to-ac converter.

20. The solar power generation system of claim 9, wherein the control unit is further configured to receive a detected current value returned by a current sensor and compare the detected current value with a predetermined current value; the control unit is used for controlling the DC-AC converter according to the comparison result so as to adjust the voltage level or the current magnitude of the detected electric energy.

Technical Field

The present disclosure relates to a solar power generation system and a detection method, and more particularly, to a technique for detecting whether a solar panel is abnormal.

Background

The principle of Solar power generation is to use Solar panels (Solar panels) made of photoelectric semiconductors to absorb sunlight and convert the light energy into electric energy to output voltage or current. However, after the solar power generation system is operated for a long time, the solar panels may have reduced performance due to various factors, such as: hit by foreign objects, or damage to internal components, etc. Therefore, periodic inspections are required to ensure that the solar power system is operating properly.

Disclosure of Invention

One embodiment of the present disclosure is a detection method for detecting a solar power generation system. The solar power generation system comprises a solar panel and an AC-DC converter, and when the AC-DC converter is in a power generation mode, photoelectric electric energy generated by the solar panel is transmitted to an external power grid through the AC-DC converter. The detection method comprises the following steps: when the direct-current/alternating-current converter enters a detection mode different from the power generation mode, the direct-current/alternating-current converter is controlled to draw electric energy from an external power grid, detection electric energy is generated and transmitted to the solar panel, and the solar panel obtains a detection result of the solar panel through a detection instrument under the condition that the detection electric energy passes through the solar panel.

Another embodiment of the present disclosure is a solar power generation system including a dc-to-ac converter and a control unit. The DC-AC converter is coupled between an external power grid and the solar panel. The control unit is coupled to the DC-AC converter and used for controlling the DC-AC converter to switch between a power generation mode and a detection mode. When the DC-AC converter is in a power generation mode, the photoelectric electric energy generated by the solar panel is converted and transmitted to an external power grid through the DC-AC converter. When the DC-AC converter is in a detection mode, the control unit controls the DC-AC converter to draw electric energy from an external power grid and generate detection electric energy to be transmitted to the solar panel, so that the solar panel obtains a detection result of the solar panel by a detection instrument under the condition that the detection electric energy passes through.

Under the condition that the solar power generation system provides detection electric energy for the solar panel, the detection instrument can detect whether the solar panel is normal or damaged easily and effectively.

Drawings

FIG. 1 is a schematic illustration of a solar power system according to some embodiments.

FIG. 2A is a schematic illustration of a solar power system according to some embodiments.

FIG. 2B is a schematic illustration of a solar power system according to some embodiments.

Fig. 3A to 3E are schematic diagrams of an ac-dc converter according to some embodiments.

FIG. 4 is a flow chart illustrating steps of a detection scheme according to some embodiments.

FIG. 5A is a schematic illustration of a solar power system according to some embodiments.

FIG. 5B is a schematic illustration of a solar power system according to some embodiments.

FIG. 6A is a schematic illustration of a solar power system according to some embodiments.

FIG. 6B is a schematic illustration of a solar power system according to some embodiments.

FIG. 7A is a schematic illustration of a solar power system according to some embodiments.

FIG. 7B is a schematic illustration of a solar power system according to some embodiments.

FIG. 8 is a schematic illustration of a solar power system according to some embodiments.

Description of reference numerals:

100: solar power generation system

110, 110A-110E: DC-AC converter

120: control unit

121: current sensor

130,130A, 130B: DC converter

131,131A, 131B: diode with a high-voltage source

132: inductance

140,740: bypass switch circuit

141,641,741,742: bypass switching element

142: one-way conduction element

521a-521 d: current sensor

541: insulated gate bipolar transistor change-over switch

542: relay with a movable contact

621a-621 d: current sensors 821a,821 b: current sensor

840: bypass switch circuit

Vs: connection node

Vc: bus voltage

C: energy storage capacitor

D: detection instrument

E: external power grid

SP, SP1-SP 4: solar panel

T1, T2: transistor switch

Ta, Ta: change-over switch

W51-W55, WA1-WA5, WB1-WB 5: switching element

S401-S408: step (ii) of

Detailed Description

Embodiments of the invention will now be described with reference to the accompanying drawings, in which a number of practical details will be set forth, but these should not be construed as limiting the invention. In some embodiments, these implementation details are not necessary. In order to simplify the drawings, some conventional structures and elements are shown in the drawings in a simple schematic manner. When an element is referred to as being "connected" or "coupled," it can be referred to as being "electrically connected" or "electrically coupled," and can also be used to indicate that two or more elements are in mutual engagement or interaction. Although terms such as "first," "second," etc. may be used herein to describe various elements, such terms are used only to distinguish one element or operation from another element or operation described in the same technical terms. Unless the context clearly dictates otherwise, the terms do not specifically refer or imply an order or sequence nor are they intended to limit the invention.

As shown in fig. 1, in one embodiment, the solar power generation system 100 at least includes a solar panel SP, an ac-dc converter 110 and a control unit 120. The dc-ac converter 110 is coupled between the external power grid E and the solar panel SP, and the control unit 120 is coupled to the dc-ac converter 110. When the solar panel SP is irradiated by sunlight, a voltage or a current is generated due to a photoelectric effect. For the convenience of the present disclosure, the aforementioned state of power generation will be referred to herein as a "power generation mode" of the solar power generation system 100 or the dc-ac converter 110. In addition, since those skilled in the art can understand the structure and principle of the solar panel SP, the description thereof is omitted. In addition to the aforementioned "power generation mode", when the solar panel SP is not irradiated by sunlight, the solar power generation system 100 can receive electric energy from the external power grid E through the dc-ac converter 110, so that the dc-ac converter 110 reversely supplies power to the solar panel SP, thereby detecting the state of the solar panel SP. The foregoing detection process is referred to herein as a "detection mode" of the solar power generation system 100 or the dc-ac converter 110.

In one embodiment, the control unit 120 is used for controlling the dc-ac converter 110 to switch between the power generation mode and the detection mode. In other words, when the dc-ac converter 110 is in the "power generation mode", the photovoltaic power generated by the solar panel SP according to the illumination is transmitted to the external power grid E through the dc-ac converter 110. On the contrary, when the dc-ac converter 110 is in the "detection mode", the control unit 120 controls the dc-ac converter 110 to draw power from the external power grid E to generate detection power, and transmits the detection power to the solar panel SP. Accordingly, when receiving the detection power, the electrical characteristics (e.g., voltage, current, impedance) or physical state (temperature) of the solar panel SP can be detected by the detection device D, thereby detecting whether there is an abnormality in each part of the solar panel SP. In one embodiment, the control unit 120 is used for performing various operations or determinations, and may be implemented by a micro control unit (microcontroller), a microprocessor (microprocessor), a digital signal processor (digital signal processor), an Application Specific Integrated Circuit (ASIC), or a logic circuit.

In some embodiments, the detecting device D can be used to detect and determine the magnitude of the detecting power flowing into the solar panel SP, for example: it is detected whether the current or voltage is abnormal. The detection instrument D may also comprise a thermography or a spectrum analyzer. In the detection mode, the thermal imaging instrument or the spectrum analyzer is used for shooting a detection image of the solar panel SP with the inflow of the detection current. Then, the inspection image is analyzed by the inspection device D or other analysis devices (e.g., the temperature is determined by the color of the image) to determine whether the solar panel is normal or damaged. The solar power generation system 100 of the present disclosure changes the electrical characteristics or physical state of the solar panel SP by supplying power in the reverse direction (i.e., obtaining the electric energy of the external grid E through the dc-ac converter 110 and supplying the power to the solar panel SP). The detection personnel simply and rapidly detect the plurality of solar panels SP through the detection instrument D, and the detection efficiency is greatly improved.

As shown in fig. 1, in some embodiments, the solar power generation system 100 further includes a dc converter 130. The dc converter 130 is coupled between the solar panel SP and the dc-ac converter 110 (e.g., connected to the bus Vc and the connection node Vs of the solar panel SP, respectively) for converting the electric energy generated by the solar panel SP. In operation, when the power generation mode is operated, the first dc voltage generated by the solar panel SP is first converted into the second dc voltage by the dc converter 130. Then, the second dc voltage is converted into an output ac voltage by the dc-ac converter 110, and the output ac voltage is transmitted to the external power grid E by the dc-ac converter 110. However, the disclosure is not limited thereto, and in other embodiments, the dc-ac converter 110 may be directly coupled to the solar panel SP without passing through the dc converter 130.

In some other embodiments, the solar power generation system 100 further includes an energy storage capacitor C coupled between the solar panel SP and the dc-to-ac converter 110 (in different embodiments, the energy storage capacitor C may also be coupled in parallel to the dc-to-ac converter 110 and the dc-to-dc converter 130). When the detection mode is operated, the energy storage capacitor C cooperates with the dc-ac converter 110 to provide detection power to the solar panel SP. For example, after the dc-ac converter 110 obtains electric energy from the external power grid E and converts the electric energy into dc voltage, the electric energy corresponding to the dc voltage may be stored in the energy storage capacitor C, and the electric energy required for the detection operation is transmitted to the solar panel SP through discharging.

In fig. 2A and 2B, similar elements and principles related to the embodiment of fig. 1 are described in the foregoing, and are not repeated. As shown in fig. 2A, in some embodiments, the solar power system 100 further includes a bypass switch circuit 140. The bypass switch circuit 140 is connected in parallel with the dc-dc converter 130 and is coupled between the solar panel SP and the dc-ac converter 110. The control unit 120 is coupled to the bypass switch circuit 140. In operation, when the detection mode is running, the control unit 120 is configured to control the bypass switch circuit 140 to be turned on, so that the detection power is transmitted from the dc-ac converter 110 to the solar panel SP via the bypass switch circuit 140. As shown in FIG. 2B, in some embodiments, the bypass switch circuit 140 includes a bypass switch element 141 and a one-way conducting element 142 (e.g., a diode). The bypass switch element 141 is coupled to the control unit 120 and is controlled by the control unit 120 to be turned on or off, thereby controlling the whole bypass switch circuit 140 to be turned on or off. The one-way conduction device 142 is used to prevent the bypass switch circuit 140 from being turned on by mistake when the dc-ac converter 110 is in the power generation mode.

In some embodiments, the dc converter 130 is a unidirectional dc converter, and is configured to receive the first dc voltage generated by the solar panel SP to generate a second dc voltage, and output the second dc voltage to the dc-ac converter 110. As shown in fig. 2A, in some embodiments, the dc converter 130 includes a diode 131 and an inductor 132, and the bypass switch circuit 140 is connected in parallel with the diode 131 and the inductor 132 of the dc converter 130. The direction of the current through the diode 131 is from the solar panel SP to the dc-to-ac converter 110. Although the circuit structure of the dc converter 130 in the embodiment shown in fig. 2B is different from that shown in fig. 2A, those skilled in the art can understand the operation manner of the dc converter 130, and details thereof are not repeated herein.

Fig. 3A-3E are schematic diagrams of the inverters 110A-110E shown according to some embodiments of the disclosure, and the inverter 110 may also be a bidirectional inverter. In fig. 3A, the dc-to-ac converter 110A at least includes two transistor switches T1 and T2. The control unit 120 can control the transistor switches T1 and T2 to switch on and off respectively, so as to switch the input and output directions of the dc-to-ac converter 110. Although the circuit structures of the dc-to-ac converters 110B to 110E in the embodiments shown in fig. 3B to 3E are different from those shown in fig. 3A, those skilled in the art can understand the circuit structures of fig. 3A to 3E and the operations thereof, and the description thereof is omitted.

The following describes the process of the solar power generation system 100 in different operation modes with reference to fig. 4 in conjunction with the solar power generation system 100 shown in fig. 2A and 2B. As shown in fig. 4, in step S401, the control unit 120 determines that the dc-ac converter 110 is to be selectively controlled in the "power generation mode" or the "detection mode". If the control unit 120 is to control the dc-ac converter 110 to the "power generation mode", it proceeds to step S402. In step S402, the control unit 120 turns off the bypass switch circuit 140. Next, in step S403, the dc converter 130 converts the first dc voltage generated by the solar panel SP into a second dc voltage. In step S404, the dc-ac converter 110 receives the second dc voltage, converts the second dc voltage into an ac voltage, and outputs the ac voltage to the external grid E.

If the control unit 120 is to control the dc-ac converter 110 in the "detection mode", it proceeds to step S405. In step S405, the control unit 120 turns on the bypass switch circuit 140. Next, in step S406, the control unit 120 controls the dc-ac converter 110 to draw power from the external grid E to generate detection power. Then, in step S407, the dc-ac converter 110 transmits the detection power to the solar panel SP through the bypass switch circuit 140. In step S408, the detecting device D detects the electrical characteristics or physical state of the solar panel SP to obtain a detection result (e.g., a detection image) and analyze whether the solar panel SP is normal or damaged.

On the other hand, in some embodiments, as shown in fig. 2A and fig. 2B, the control unit 120 detects a voltage difference between the dc-ac converter 110 and the solar panel SP, and controls the on/off state of the bypass switch circuit 140 according to the detection result. In one embodiment, the control unit 120 is configured to detect whether the bus voltage Vc between the dc-to-ac converter 110 and the dc-to-dc converter 130 is zero (i.e., detect whether the voltage across the energy storage capacitor C is zero), so as to prevent the residual voltage from damaging the internal circuit of the solar power generation system 100. In another embodiment, the control unit 120 detects whether the bus voltage Vc is equal to the voltage at the connection node Vs of the solar panel SP to determine whether there is a residual voltage in the solar power generation system 100.

For example, in operation, if the power generation mode is to be re-entered after the detection is completed, the control unit 120 controls the dc-ac converter 110 to stop generating the detection power. Next, the control unit 120 detects whether the bus voltage Vc between the dc-ac converter 110 and the dc-dc converter 130 is zero or whether the bus voltage Vc and the voltage at the connection node Vs of the solar panel SP are equal to each other. If the bus voltage Vc is zero or the bus voltage Vc is equal to the voltage at the connection node Vs, the control unit 120 controls the bypass switch circuit 140 to switch from the on state to the off state. Similarly, if the power generation mode is performed for a period of time, and the detection mode is to be entered, the control unit 120 controls the bypass switch circuit 140 to switch from the off state to the on state. The control unit 120 then controls the dc-to-ac converter 110 to draw power from the external grid E to generate the detection power.

In the detection mode, the control unit 120 can adjust the voltage level or the current level of the detected electrical energy. Referring to fig. 2A, in some embodiments, the solar power generation system 100 further includes a current sensor 121. The current sensor 121 is coupled to the control unit 120 for detecting the magnitude of the current flowing into the solar panel SP and transmitting the detected magnitude of the current back to the control unit 120, so that the control unit 120 can adjust the current flowing into the solar panel SP according to the detected magnitude of the current.

In some embodiments, the solar power generation system 100 includes a set current value. By setting the set current value, the current flowing into the solar panel SP is not too high to cause damage to the solar panel SP. The set current value can be preset, or can be input by the user or adjusted at any time. After the control unit 120 receives the detected current value returned by the current sensor 121, the control unit 120 compares the detected current value with the set current value, and controls the dc-ac converter 110 according to the comparison result, so that the dc-ac converter 110 changes the magnitude of the output detected power. For example, when the detected current value is larger than the set current value, the voltage level or the current magnitude of the detected electric energy is reduced; when the detected current value is smaller than the set current value, the voltage level or the current magnitude of the detected electric energy is increased. In some embodiments, the current value is set to a desired current range of the dc-ac converter 110 in the "detection mode". The value or range of the set current value may be set by the user.

The detection method can also be applied to simultaneously detect a plurality of groups of solar panels. In fig. 5A and 5B, similar elements and principles related to the embodiment of fig. 1 are described in the foregoing, and are not repeated. As shown in fig. 5A, the solar power generation system 500 includes a plurality of switching elements W51 to W55. The bypass switch circuit 140 is coupled to the solar panel SP1 through the switch elements W51, W52, W53, and to another solar panel SP2 through the switch elements W51, W54, W55. The two solar panels SP1, SP2 are coupled in parallel to each other. In the inspection mode, if the switching devices W51-W55 are all turned on, the solar power generation system 500 can simultaneously provide inspection power to the solar panels SP1 and SP 2. The detecting instrument D (such as a thermal imaging instrument or a spectrum analyzer) can simultaneously detect the electrical characteristics or the physical states of the solar panels SP1 and SP 2.

Accordingly, if the switching elements W51, W52, and W53 are turned on and the switching elements W54 and W55 are turned off, the solar power generation system 500 will only provide the detection power to the solar panel SP 1. Similarly, if the switching elements W51, W54, W55 are turned on and the switching elements W52, W53 are turned off, the solar power generation system 500 will only provide the detection power to the solar panel SP 2. The control unit 120 can control the bypass switch circuit 140 to switch the mode when the voltage difference between the dc-ac converter 110 and the solar panel SP is zero. In other embodiments, as shown in fig. 5B, the solar power generation system 500 can be coupled to the solar panels SP1, SP2 through the switch elements W51, W52, W54 (i.e., without providing the switch elements W53, W55), and can also selectively detect different solar panels SP1, SP 2. The operation of the switching elements W51, W52, W54 is similar to that described above. In some embodiments, the bypass switch circuit 140 shown in fig. 5A and 5B may include a bidirectional switch element, such as an Insulated Gate Bipolar Transistor (IGBT) switch 541 or a relay 542, but not limited thereto.

In one embodiment, as shown in fig. 5A, the solar power generation system 100 detects the current flowing through the switching elements W52 and W54 by the current sensors 521a and 521b, respectively, and can calculate the current flowing through the switching element W51. The current sensors 521a and 521b operate in the same manner as the embodiment shown in fig. 2A, and are electrically connected to the control unit 120 to return the detected data to the control unit 120. In one embodiment, as shown in fig. 5B, the solar power generation system 100 detects the current flowing through the switching elements W51 and W54 by the current sensors 521a and 521B, respectively, and calculates the current flowing through the switching element W52 accordingly.

In some embodiments, the control unit 120 can also receive the detected current values returned by all the current sensors 521a and 521 b. The control unit 120 compares all the detected current values with the set current value, and controls the dc-ac converter 110 according to the comparison result, so that the dc-ac converter 110 changes the voltage level or the current magnitude of the output detected power. In some embodiments, as long as one of the detected current values is greater than the set current value (or the control unit 120 compares the maximum detected current value with the set current value), the control unit 120 controls the dc-ac converter 110 to reduce the detected power.

When the solar panels with large quantity are detected, the direct-current converter and the alternating-current converter of the solar power generation system can be connected with the multiple groups of direct-current converters in parallel, and then the multiple groups of direct-current converters are connected with the multiple groups of solar panels in parallel, so that the efficiency of the direct-current converter in a power generation mode is improved. In fig. 6A and 6B, similar elements and principles related to the embodiment of fig. 1 are described in the foregoing, and are not repeated.

As shown in fig. 6A, the dc-ac converter 110 is coupled to two sets of dc converters 130A, 130B. The bypass switch circuit 140 is connected to the switching elements WA1, WB1 through two paths, respectively. Switching element WA1 is in turn connected to solar panels SP1, SP2 via switching elements WA2, WA4, respectively, and to switching elements WA3, WA 5. The switching element WB1 is connected to the solar panels SP3 and SP4 via the switching elements WB2 and WA4, respectively, and is connected to the switching elements WB3 and WB 5. The bypass switch circuit 140 includes a bypass switch element 641 (e.g., an insulated gate bipolar transistor switch) and two unidirectional conducting elements 142. When the bypass switch 641 is controlled by the control unit 120 to be turned on, the solar panels SP1-SP4 can be detected as described above. Similarly, the bypass switch circuit 140 of FIG. 6B includes two mutually coupled bypass switch elements 641, 642 (e.g., IGBTs) and a unidirectional conducting element 142. When the bypass switching element 641 and the corresponding switching elements WA1 to WA5 are turned on, the solar power generation system 600 detects the solar panels SP1 to SP 2. Conversely, when the bypass switch 642 and the corresponding switching elements WB1 to WB5 are turned on, the solar power generation system 600 detects the solar panels SP3 to SP 4. In some other embodiments, the solar power generation system 600 may provide a separate set of bypass switch elements 641, 642 for each solar panel SP1, SP2 to switch the detection mode and the power generation mode.

In one embodiment, as shown in fig. 6A and 6B, the solar power generation system 100 detects the magnitude of the current flowing through the switching elements WA2 and WA4 connected to the solar panel SP2 through the current sensors 621a and 621B, respectively, and can calculate the magnitude of the current flowing through the switching element WA1 accordingly. Similarly, the solar power generation system 100 detects the magnitude of the current flowing through the switching elements WB2 and WB4 connected to the solar panel SP4 through the current sensors 621c and 621d, respectively, and can calculate the magnitude of the current flowing through the switching element WB1 accordingly. In addition, a current sensor may be installed between the switching elements WA1 and WA4 to calculate the current flowing through the switching element WA 2.

The "bypass switch circuit" and the "bypass switch element" in the present disclosure are not limited to those shown in fig. 1 to 6B, and both circuits capable of forming a transmission detection power path between the dc-ac converter and the solar panel in the detection mode can be used as the "bypass switch circuit" and the "bypass switch element". In fig. 7A, similar elements and principles related to the embodiment of fig. 5A are described in the foregoing, and are not repeated. As shown, in some embodiments, the bypass switch circuit 740 may include or be switched with an insulated gate bipolar transistor. In the detection mode, the control unit 120 controls the switch of the insulated gate bipolar transistor to be turned on, so that the detection power is transmitted to the solar panel SP1 or SP2 through the bypass switch circuit 740. In some embodiments, the dc converter 130 in the solar power generation system 700 includes a diode 131. In this case, the parasitic diode within the insulated gate bipolar transistor switch may act as a diode. For example, the dc converter 130 includes the diode 131, and the diode 131 may be implemented by a parasitic diode of an insulated gate bipolar transistor switch in the bypass switch circuit 740. Diode 131 is also coupled in parallel with the insulated gate bipolar transistor switch (similar to the circuit of fig. 5A). Fig. 7B is a schematic diagram of a solar power generation system 700 according to various embodiments of the disclosure, and similar elements and principles related to the embodiment of fig. 6B have been previously described and are not repeated. The bypass switch circuit includes bypass switch elements 741 and 742, and parasitic diodes of the elements can be used as the diodes 131A and 131B of the dc converters 130A and 130B, respectively.

As shown in fig. 8, in this embodiment, the bypass switching circuit 840 and the dc converter 130 of the solar power generation device 800 are coupled to the controlled switch 850 and the switching elements WA to WAC. The dc converter 130 further includes two switches Ta and Tb. The control ends of the switches Ta and Tb are coupled to the control unit 120, and can be controlled by the control unit 120 to be turned on or off. In the power generation mode, the switching elements WA to WC and the selector switches Ta to Tb are controlled to be on, and the bypass switch circuit 840 and the controlled switch 850 are turned off. At this time, the parasitic diode in the bypass switch circuit 840 will act as the diode 131 within the dc converter 130. The photovoltaic power generated by the solar panels SP1, SP2 can be output to the external power grid E through the parasitic diodes of the controlled switch 850, processed by the dc converter 130 and the dc-ac converter 110. On the other hand, in the detection mode, the bypass switching circuit 840, the controlled switch 850, and the switching elements WA to WAC are turned on, and the changeover switches Ta and Tb are turned off, so that the dc converter 130 is turned off. At this time, the dc-ac converter 110 will be able to draw power from the external power grid E to transmit the detection power to the solar panels SP1, SP2 through the bypass switch circuit 840 and the conducted controlled switch 850.

Similar to the previous embodiment, in one embodiment, as shown in fig. 8, the solar power generation system 100 detects the magnitude of the current flowing through the switching elements WA and WB connected to the solar panel SP2 through the current sensors 821a and 821b, respectively, and can calculate the magnitude of the current flowing through the switching element WC accordingly.