Anti-potential-induced-degradation circuit and photovoltaic power generation system

Abstract

The utility model provides an anti-potential-induced-degradation circuit and a photovoltaic power generation system, and relates to the technical field of photovoltaic power generation. The anti-potential-induced-degradation circuit comprises a primary side circuit and a secondary side circuit, wherein the primary side circuit comprises a first switching element and a primary side winding of a transformer; the secondary circuit comprises a secondary winding of the transformer; the first end of the second switch piece is connected with the first end of the secondary winding; the first end of the first energy storage element is connected with the second end of the second switch piece, and the first end of the first energy storage element is connected with the negative electrode of the photovoltaic module; the first end of the second energy storage element is connected with the second end of the first energy storage element, and the second end of the second energy storage element is connected with the grounding end of the photovoltaic module; the first end of the third switch piece is connected with the second end of the second energy storage element, and the second end of the third switch piece is connected with the first end of the secondary winding. According to the invention, the size and the cost of the anti-potential-induced-attenuation circuit are reduced, and the anti-electromagnetic interference capability of the transformer is also improved.

Description

Technical Field

[0001] The present application relates to the technical field of photovoltaic power generation, and in particular to an anti-potential induced degradation circuit and a photovoltaic power generation system. Background Art

[0002] A photovoltaic power generation system consists of photovoltaic modules and an inverter circuit. The positive and negative terminals of the photovoltaic modules are connected to the inverter circuit's electrical signal input terminals, while the inverter circuit's electrical signal output terminals are connected to the AC power grid. During operation, a negative voltage is generated between the negative terminal of the photovoltaic module and the ground terminal. This negative voltage reduces the output power of the entire photovoltaic power generation system, which is called potential-induced degradation.

[0003] In the related art, a DC voltage source is generated by adding a voltage conversion unit to the inverter circuit of the photovoltaic power generation system, and the potential induced decay is repaired by transmitting the DC voltage to the photovoltaic module. However, since the negative voltage between the negative pole and the grounded metal frame of the photovoltaic module is relatively high when working during the day, the number of turns of the transformer winding required to be set in the voltage conversion unit is relatively large, resulting in a larger overall circuit volume of the photovoltaic power generation system and higher cost. Utility Model Content

[0004] The present application aims to solve the technical problems in the prior art or related art of photovoltaic power generation systems, such as large overall circuit volume and high cost.

[0005] To this end, a first aspect of the present application proposes an anti-potential induced degradation circuit.

[0006] A second aspect of the present application provides a photovoltaic power generation system.

[0007] In view of this, according to the first aspect of the present application, an anti-potential induced attenuation circuit is proposed, which is applied to a photovoltaic module. The anti-potential induced attenuation circuit includes: a primary circuit, the primary circuit includes a first switch and a primary winding of a transformer, the first end of the primary winding is connected to the positive pole of the power supply, the second end of the primary winding is connected to the first end of the first switch, and the second end of the first switch is connected to the negative pole of the power supply; a secondary circuit, the secondary circuit includes: a secondary winding of the transformer, coupled to the primary winding; a second switch, the first end of the second switch is connected to the first end of the secondary winding end is connected; a first energy storage element, the first end of the first energy storage element is connected to the second end of the second switch element, and the first end of the first energy storage element is connected to the negative electrode of the photovoltaic component; a second energy storage element, the first end of the second energy storage element is connected to the second end of the first energy storage element, and the first end of the second energy storage element is connected to the second end of the secondary winding, and the second end of the second energy storage element is connected to the ground terminal of the photovoltaic component; a third switch element, the first end of the third switch element is connected to the second end of the second energy storage element, and the second end of the third switch element is connected to the first end of the secondary winding.

[0008] In this technical solution, the anti-electromotive force induced degradation circuit includes a primary circuit, a secondary circuit, and a transformer. The primary winding of the transformer is arranged in the primary circuit, i.e., the primary winding in the primary circuit, and the secondary winding of the transformer is arranged in the secondary circuit, i.e., the secondary winding in the secondary circuit.

[0009] In this technical solution, the primary winding is connected to a power supply, which supplies power to the primary winding. A first end of the primary winding is connected to the positive terminal of a DC power supply. The primary circuit also includes a first switch element, connected between the second end of the primary winding and the negative terminal of the power supply. By controlling the on / off state of the first switch element, the application of voltage to the primary winding is controlled. When voltage is applied to the primary winding, an alternating magnetic field is generated in the iron core, causing the secondary winding in the secondary circuit to generate a voltage signal under the influence of the magnetic field.

[0010] It should be noted that the power supply connected to the primary winding may be a DC power supply, and the DC power supply may be a DC power supply obtained from the output end of the inverter circuit.

[0011] In this technical solution, the secondary circuit also includes a second switch, a third switch, a first energy storage element, and a second energy storage element. The second switch and the first energy storage element form a first energy storage loop, while the third switch and the second energy storage element form a second energy storage loop. By controlling the on / off state of the first switch in the primary circuit, the first and second energy storage loops are controlled to alternate between energy storage states.

[0012] Specifically, the first switch in the primary circuit is controlled to be in the on state, and the primary winding of the transformer is in the energy storage state. At this time, the first end of the secondary winding is the negative pole, the second end of the secondary winding is the positive pole, the third switch is in the on state, and the second switch is in the off state. The second energy storage element is charged through the second energy storage circuit, and the charging voltage is such that the first end of the first energy storage element is a positive voltage and the second end of the first energy storage element is a negative voltage. The first switch in the primary circuit is controlled to be in the off state, and the primary winding of the transformer releases the stored energy. At this time, the first end of the secondary winding is the positive pole and the second end of the secondary winding is the negative pole, the second switch is in the on state, and the third switch is in the off state. The first energy storage element is charged through the first energy storage circuit, and the charging voltage is such that the first end of the second energy storage element is a positive voltage and the second end of the second energy storage element is a negative voltage.

[0013] When the first switch is in the on state, the first end of the secondary winding is the negative pole, and the second end of the secondary winding is the positive pole. The current in the second energy storage loop starts from the positive pole of the secondary winding, passes through the second energy storage element and the third switch, and then flows to the negative pole of the secondary winding. When the first switch is in the off state, the first end of the secondary winding is the negative pole, and the second end of the secondary winding is the positive pole. The current in the first energy storage loop starts from the positive pole of the secondary winding, passes through the second switch and the first energy storage element, and then flows to the negative pole of the secondary winding.

[0014] In this technical solution, the first end of the first energy storage element is connected to the negative pole of the photovoltaic module, and the second end of the second energy storage element is connected to the ground terminal of the photovoltaic module. Therefore, the repair voltage of the anti-potential induced degradation circuit when repairing the potential induced degradation effect of the photovoltaic module is numerically equal to the voltage on the first energy storage element when the first switch in the primary circuit is turned on and the voltage on the secondary winding when the first switch in the primary circuit is disconnected.

[0015] In the technical solution of the present application, when the voltage that the anti-potential induced attenuation circuit needs to output is a fixed value, since part of the voltage can be provided by the first energy storage element, compared with the solution in the related art in which the voltage on the capacitor is entirely provided by the voltage on the secondary winding, the voltage at the secondary winding of the first switch element in the primary circuit when it is disconnected can be reduced, and since the voltage on the secondary winding is proportional to the number of turns of the secondary winding, the voltage on the secondary winding of the first switch element in the primary circuit in the disconnected state can be reduced, the number of turns of the secondary winding can be reduced, the volume and cost of the anti-potential induced attenuation circuit are reduced, and the anti-electromagnetic interference ability of the transformer is improved.

[0016] In some technical solutions, optionally, when the first switch element is in the on state, the third switch element is on, and the second switch element is off; when the first switch element is in the off state, the second switch element is on, and the third switch element is off.

[0017] In this technical solution, the first switch in the primary circuit is controlled to be in the on state, and the primary winding of the transformer is in the energy storage state. At this time, the third switch is in the on state, and the second switch is in the off state. The second energy storage element is charged through the second energy storage circuit, and the charging voltage is a positive voltage at the first end of the first energy storage element and a negative voltage at the second end of the first energy storage element. The first switch in the primary circuit is controlled to be in the off state, and the primary winding of the transformer releases the stored energy. At this time, the second switch is in the on state, and the third switch is in the off state. The first energy storage element is charged through the first energy storage circuit, and the charging voltage is a positive voltage at the first end of the second energy storage element and a negative voltage at the second end of the second energy storage element.

[0018] In the technical solution of the present application, the on-off state of the second switch element and the third switch element can automatically switch the on-off state in response to the on-off state of the first switch element, thereby adjusting the current flow direction in the secondary circuit, so that when the voltage required to be output by the anti-electromotive force induced attenuation circuit is a fixed value, part of the voltage can be provided by the first energy storage element, thereby reducing the number of turns of the secondary winding, thereby reducing the volume and cost of the transformer, and also improving the transformer's ability to resist electromagnetic interference.

[0019] In some technical solutions, optionally, the second switching element includes a first diode, the first end of the first diode is connected to the first end of the secondary winding, and the second end of the first diode is connected to the negative pole of the photovoltaic component; wherein, the first end to the second end of the first diode is unidirectionally conductive.

[0020] In the technical solution of the present application, the second switching element can be optionally a diode. Specifically, the first diode is arranged as the second switching element between the first end of the secondary winding and the negative pole of the photovoltaic component, and the second end of the first diode is also connected to the first end of the first energy storage element.

[0021] Specifically, when the first switch is in the off state, the current signal at the positive pole of the secondary winding is transmitted from the first end to the second end of the first diode. Since the first end to the second end of the first diode is unidirectionally conductive, the first energy storage element can be charged at this time.

[0022] In the technical solution of the present application, the second switch element is set as a first diode, and the first end to the second end of the first diode are unidirectionally conductive. When the first switch element is in the disconnected state, the first end of the secondary winding serves as the positive electrode, and the second end of the secondary winding serves as the negative electrode, so that the second switch element can be in the on state, and the path between the secondary winding and the first energy storage element is in the on state, so that the first energy storage element is charged when the first switch element is disconnected.

[0023] In some technical solutions, optionally, the second switching element includes a first diode, the first end of the first diode is connected to the first end of the secondary winding, and the second end of the first diode is connected to the negative pole of the photovoltaic component; wherein, the first end to the second end of the first diode is unidirectionally conductive.

[0024] In the technical solution of the present application, the third switching element can be optionally a diode. Specifically, the second diode is arranged as the third switching element between the first end of the secondary winding and the second end of the second energy storage element, and the first end of the second diode is also connected to the ground end of the photovoltaic component.

[0025] Specifically, when the first switch is in the on state, the current signal at the positive pole of the secondary winding is transmitted from the first end to the second end of the second diode. Since the second diode is unidirectionally conductive from the first end to the second end, the second energy storage element can be charged at this time.

[0026] In the technical solution of the present application, the third switch element is set as a second diode, and the first end of the second diode is unidirectionally conductive to the second end. When the first switch element is in the on state, the second end of the secondary winding serves as the positive electrode and the first end of the secondary winding serves as the negative electrode, so that the third switch element can be in the on state, and the path between the secondary winding and the first energy storage element is in the on state, so that the first energy storage element is charged when the first switch element is disconnected.

[0027] In some technical solutions, optionally, the first energy storage element includes: at least one first capacitor, the positive electrode of the at least one first capacitor is connected to the second end of the first switch element; the second energy storage element includes: at least one second capacitor, the positive electrode of the at least one second capacitor is connected to the negative electrode of the at least one first capacitor, and the negative electrode of the at least one second capacitor is connected to the ground terminal of the photovoltaic component.

[0028] In the technical solution of this application, the first energy storage element can be provided with at least one first capacitor, and the second energy storage element can be provided with at least one second capacitor. By using the first capacitor and the second capacitor as the first energy storage element and the second energy storage element, respectively, the stability of energy storage can be ensured, thereby improving the effectiveness of the anti-potential induced degradation circuit in repairing the anti-potential induced effect of the photovoltaic module.

[0029] It should be noted that the number of the first capacitor and the second capacitor is not limited, and when there are multiple first capacitors or multiple second capacitors, the connection method between the multiple first capacitors and the connection method between the multiple second capacitors are also not limited.

[0030] Specifically, the positive electrode of the first capacitor serves as the first end of the first energy storage element, and the negative electrode of the first capacitor serves as the second end of the first energy storage element. The positive electrode of the second capacitor serves as the first end of the second energy storage element, and the negative electrode of the second capacitor serves as the second end of the second energy storage element.

[0031] In some technical solutions, optionally, the anti-potential induced degradation circuit further includes:

[0032] A fourth switch element, wherein a first end of the fourth switch element is connected to the first end of the first energy storage element, and a second end of the fourth switch element is connected to the negative electrode of the photovoltaic assembly.

[0033] In this technical solution, the anti-potential-induced degradation circuit also includes a fourth switch element, which is positioned between the first energy storage element and the negative electrode of the photovoltaic module. When the fourth switch element is in the on state, the anti-potential-induced degradation circuit is connected to the photovoltaic module, and the anti-potential-induced degradation circuit can compensate for the potential-induced degradation effect of the photovoltaic module. When the fourth switch element is in the off state, the anti-potential-induced degradation circuit is disconnected from the photovoltaic module, and the anti-potential-induced degradation circuit has no effect on the photovoltaic module.

[0034] In the technical solution of the present application, a fourth switch is provided between the first end of the first energy storage element and the photovoltaic assembly, so that the conduction state between the anti-potential induced decay circuit and the photovoltaic assembly can be controlled by controlling the on-off state of the fourth switch, thereby improving the flexibility of circuit control.

[0035] In some technical solutions, optionally, the anti-electromotive force induced attenuation circuit further includes: a controller, which is connected to the control end of the first switching element and the control end of the fourth switching element, and is used to control the first switching element to switch between the on state and the off state according to a preset frequency when the fourth switching element is in the on state.

[0036] In this technical solution, a controller is also provided in the anti-electromotive force induced attenuation circuit, which is connected to the control end of the first switching element and the control end of the fourth switching element. The controller can control the on-off state of the first switching element and the on-off state of the fourth switching element, thereby controlling the operation of the anti-electromotive force induced attenuation circuit.

[0037] Specifically, when the anti-potential induced degradation circuit is needed to repair the potential induced degradation effect of the photovoltaic module, the controller controls the fourth switch element to be in the on state, thereby connecting the anti-potential induced degradation circuit to the photovoltaic module. When the anti-potential induced degradation circuit is no longer needed to repair the potential induced degradation effect of the photovoltaic module, the controller controls the fourth switch element to be in the off state, thereby disconnecting the anti-potential induced degradation circuit from the photovoltaic module.

[0038] When the fourth switch is in the on state, the controller controls the first switch to alternately switch between the on and off states. When the first switch is in the on state, the primary winding of the transformer is in an energy storage state. At this time, the first end of the secondary winding is a negative electrode, and the second end of the secondary winding is a positive electrode. The third switch is in the on state, and the second switch is in the off state. The second energy storage element is charged via the second energy storage circuit, and the charging voltage is such that the first end of the first energy storage element is a positive voltage, and the second end of the first energy storage element is a negative voltage. When the first switch in the primary circuit is controlled to be in the off state, the primary winding of the transformer releases stored energy. At this time, the first end of the secondary winding is a positive electrode, and the second end of the secondary winding is a negative electrode. The second switch is in the on state, and the third switch is in the off state. The first energy storage element is charged via the first energy storage circuit, and the charging voltage is such that the first end of the second energy storage element is a positive voltage, and the second end of the second energy storage element is a negative voltage.

[0039] In the technical solution of the present application, by setting a corresponding controller in the anti-potential induced degradation circuit and controlling the conduction state of the first switch element and the fourth switch element through the controller, the control of the anti-potential induced degradation circuit to repair the potential induced degradation effect of the photovoltaic module is achieved, thereby improving the controllability of the anti-potential induced degradation circuit.

[0040] According to the second aspect of the present application, a photovoltaic power generation system is proposed, including: a photovoltaic module and an anti-potential induced attenuation circuit. The anti-potential induced attenuation circuit is the anti-potential induced attenuation circuit in any of the above-mentioned technical solutions. The anti-potential induced attenuation circuit is connected to the photovoltaic module, and thus has all the beneficial technical effects of the anti-potential induced attenuation circuit in any of the above-mentioned technical solutions, which will not be repeated here.

[0041] In some technical solutions, optionally, the photovoltaic power generation system further includes: an inverter circuit, wherein the input end of the inverter circuit is connected to the photovoltaic module, and the output end of the inverter circuit is connected to the anti-electromotive force induced degradation circuit.

[0042] In the technical solution of this application, a photovoltaic power generation system includes photovoltaic modules. When exposed to light, the photovoltaic modules generate a DC voltage signal, which is converted into an AC voltage signal by an inverter circuit. The AC voltage signal output by the inverter circuit is converted into a DC voltage signal and then transmitted to an anti-potential induced decay circuit, thereby powering the primary circuit of the anti-potential induced decay circuit.

[0043] In some technical solutions, optionally, the photovoltaic power generation system further includes: a battery assembly connected to the positive electrode and the negative electrode of the photovoltaic assembly.

[0044] In the technical solution of the present application, a battery assembly is provided in the photovoltaic power generation system, and the electric energy generated by the photovoltaic assembly is stored by the battery assembly.

[0045] Additional aspects and advantages of the present application will become apparent in the following description or may be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0047] Figure 1 A circuit diagram of an anti-potential induced degradation circuit provided in some embodiments of the present application is shown;

[0048] Figure 2 shows a circuit diagram of a photovoltaic power generation system provided in some embodiments of the present application;

[0049] Figure 3 shows one of the current direction schematic diagrams of the secondary circuit provided in some embodiments of the present application;

[0050] Figure 4 FIG2 shows a second schematic diagram of the current direction of the secondary circuit provided in some embodiments of the present application;

[0051] Figure 5 A circuit diagram of a photovoltaic power supply system in related art is shown.

[0052] The reference numerals are as follows:

[0053] 100 Anti-potential induced degradation circuit, 110 Primary circuit, 120 Secondary circuit, 121 Second switch element, 122 First energy storage element, 123 Second energy storage element, 124 Third switch element, 125 Controller, 130 Transformer, K1 First switch element, L1 Primary winding, L2 Secondary winding, D1 First diode, D2 Second diode, C1 First capacitor, C2 Second capacitor, K4 Fourth switch element, 200 Photovoltaic power generation system, 201 Photovoltaic module, 202 Inverter circuit, 203 Battery module, 204 Rectifier circuit, Pe Ground terminal, PV- Negative pole of photovoltaic module, PV+ Positive pole of photovoltaic module. DETAILED DESCRIPTION

[0054] In order to more clearly understand the above-mentioned objectives, features and advantages of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the features of this embodiment and the embodiments can be combined with each other.

[0055] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0056] Refer to the following Figures 1 to 4 An anti-potential induced degradation circuit and a photovoltaic power generation system according to some embodiments of the present application are described.

[0057] According to some embodiments of the present application, Figure 1 FIG2 shows a circuit diagram of an anti-potential induced degradation circuit provided in some embodiments of the present application. Figure 2 Schematic diagram of a photovoltaic power generation system provided in some embodiments of the present application is shown. Figure 1 and Figure 2As shown, an anti-potential induced attenuation circuit 100 is proposed and applied to a photovoltaic module 201. The anti-potential induced attenuation circuit 100 includes: a primary circuit 110, the primary circuit 110 includes a first switch K1 and a primary winding L1 of a transformer 130, a first end of the primary winding L1 is connected to the positive pole of the power supply, a second end of the primary winding L1 is connected to the first end of the first switch K1, and a second end of the first switch K1 is connected to the negative pole of the power supply; a secondary circuit 120, the secondary circuit 120 includes: a secondary winding L2 of the transformer 130, coupled to the primary winding L1; a second switch 121, a first end of the second switch 121 is connected to a first end of the secondary winding L2; a first storage Energy element 122, the first end of the first energy storage element 122 is connected to the second end of the second switch element 121, and the first end of the first energy storage element 122 is connected to the negative pole PV- of the photovoltaic module 201; the second energy storage element 123, the first end of the second energy storage element 123 is connected to the second end of the first energy storage element 122, and the first end of the second energy storage element 123 is connected to the second end of the secondary winding L2, and the second end of the second energy storage element 123 is connected to the ground terminal Pe of the photovoltaic module 201; the third switch element 124, the first end of the third switch element 124 is connected to the second end of the second energy storage element 123, and the second end of the third switch element 124 is connected to the first end of the secondary winding L2.

[0058] like Figure 2 As shown, a photovoltaic power generation system 200 includes a photovoltaic module 201. The positive electrode PV+ of the photovoltaic module 201 and the negative electrode PV- of the photovoltaic module 201 are connected to an inverter circuit 202. When irradiated by light, the photovoltaic module 201 can generate a DC voltage signal, which is converted into an AC voltage signal by the inverter circuit 202. Because the negative voltage generated between the negative electrode PV- of the photovoltaic module 201 and the ground terminal Pe can reduce the output power of the photovoltaic power generation system 200, an anti-potential induced degradation circuit 100 in an embodiment of the present application is connected to the photovoltaic module 201. The anti-potential induced degradation circuit 100 can generate a DC voltage. By transmitting the DC voltage generated by the anti-potential induced degradation circuit 100 between the negative electrode PV- of the photovoltaic module 201 and the ground terminal Pe, the DC voltage generated by the anti-potential induced degradation circuit 100 is opposite to the DC voltage between the negative electrode PV- of the photovoltaic module 201 and the ground terminal Pe. Therefore, the anti-potential induced degradation circuit 100 can repair and compensate for the potential induced degradation effect generated by the photovoltaic module 201.

[0059] In this embodiment, the circuit for resisting electromotive force induced degradation 100 includes a primary circuit 110, a secondary circuit 120, and a transformer 130. The primary winding of the transformer 130 is disposed in the primary circuit 110, namely, the primary winding L1 in the primary circuit 110, and the secondary winding of the transformer 130 is disposed in the secondary circuit 120, namely, the secondary winding L2 in the secondary circuit 120.

[0060] Exemplarily, the primary winding L1 and the secondary winding L2 may be located on the same iron core.

[0061] In this embodiment, the primary winding L1 is connected to a power supply, which supplies power to the primary winding L1. A first end of the primary winding L1 is connected to the positive terminal of the DC power supply. The primary circuit 110 also includes a first switch K1, which is connected between the second end of the primary winding L1 and the negative terminal of the power supply. By controlling the on / off state of the first switch K1, the application of voltage to the primary winding L1 is controlled. When voltage is applied to the primary winding L1, an alternating magnetic field is generated in the iron core, causing the secondary winding L2 in the secondary circuit 120 to generate a voltage signal under the influence of this magnetic field.

[0062] It should be noted that the power source connected to the primary winding L1 may be a DC power source, and the DC power source may be a DC power source obtained from the output terminal of the inverter circuit 202 .

[0063] Exemplarily, a rectifier circuit 204 is provided between the primary winding L1 and the inverter circuit 202 , and the rectifier circuit 204 converts the current electrical signal output by the inverter circuit 202 into a direct current electrical signal and transmits it to the primary winding L1 .

[0064] In this embodiment, the secondary circuit 120 further includes a second switch 121, a third switch 124, a first energy storage element 122, and a second energy storage element 123. The second switch 121 and the first energy storage element 122 form a first energy storage loop, and the third switch 124 and the second energy storage element 123 form a second energy storage loop. By controlling the on / off state of the first switch K1 in the primary circuit 110, the first and second energy storage loops are controlled to alternately store energy.

[0065] Specifically, the first switch K1 in the primary circuit 110 is controlled to be in the on state, and the primary winding L1 of the transformer 130 is in the energy storage state. At this time, the first end of the secondary winding L2 is the negative pole, the second end of the secondary winding L2 is the positive pole, the third switch 124 is in the on state, and the second switch 121 is in the off state. The second energy storage element 123 is charged through the second energy storage circuit, and the charging voltage is that the first end of the first energy storage element 122 is a positive voltage, and the second end of the first energy storage element 122 is a negative voltage. The first switch K1 in the control primary circuit 110 is in the disconnected state, and the primary winding L1 of the transformer 130 releases the stored energy. At this time, the first end of the secondary winding L2 is the positive pole, the second end of the secondary winding L2 is the negative pole, the second switch 121 is in the on state, and the third switch 124 is in the off state. The first energy storage element 122 is charged through the first energy storage circuit, and the charging voltage is the first end of the second energy storage element 123 is a positive voltage, and the second end of the second energy storage element 123 is a negative voltage.

[0066] Figure 3 shows one of the current direction schematic diagrams of the secondary circuit provided in some embodiments of the present application, Figure 4 FIG2 shows a second schematic diagram of the current direction of the secondary circuit provided in some embodiments of the present application, such as Figures 1 to 4 As shown, the first switch K1 is in the on state. At this time, the first end of the secondary winding L2 is the negative electrode, and the second end of the secondary winding L2 is the positive electrode. The current direction of the second energy storage loop is starting from the positive electrode of the secondary winding L2, passing through the second energy storage element 123 and the third switch 124 in sequence, and then flowing to the negative electrode of the secondary winding L2. The first switch K1 is in the off state. At this time, the first end of the secondary winding L2 is the negative electrode, and the second end of the secondary winding L2 is the positive electrode. The current direction of the first energy storage loop is starting from the positive electrode of the secondary winding L2, passing through the second switch 121 and the first energy storage element 122 in sequence, and then flowing to the negative electrode of the secondary winding L2.

[0067] In this embodiment, the first end of the first energy storage element 122 is connected to the negative pole PV- of the photovoltaic component 201, and the second end of the second energy storage element 123 is connected to the ground terminal Pe of the photovoltaic component 201. Therefore, the repair voltage of the anti-potential induced degradation circuit 100 when repairing the potential induced degradation effect of the photovoltaic component 201 is numerically equal to the voltage on the first energy storage element 122 when the first switch K1 of the primary circuit 110 is turned on and the voltage on the secondary winding L2 when the first switch K1 in the primary circuit 110 is disconnected.

[0068] Figure 5 A circuit diagram of a photovoltaic power supply system in related art is shown. Figure 5As shown, in the related art, a voltage conversion unit is added to the inverter circuit of the photovoltaic power generation system to generate a DC voltage source, which is then applied between the negative pole of the photovoltaic module and the ground terminal. The direction of the generated DC voltage source is opposite to the direction of the DC voltage between the negative pole and the ground terminal of the photovoltaic module during daytime operation, thereby achieving the effect of repairing potential induced degradation. The voltage conversion unit includes two parts: a primary circuit and a secondary circuit. The input of the primary circuit is the phase voltage or line voltage of the mains power, and the primary circuit provides energy to the secondary circuit by controlling the switch. The secondary circuit includes a winding L, a diode D, and a capacitor C. The winding L is used to provide the DC voltage source required by the secondary circuit. The diode D and the capacitor C are connected in series. One end of the capacitor C is grounded, and the other end of the capacitor C is connected to the negative pole of the photovoltaic module through a switch K. In a specific implementation, when the control switch of the primary circuit controls the primary circuit to be turned on, the primary circuit stores energy on the iron core. Then, when the control switch of the primary circuit controls the primary circuit to be turned off, the energy stored in the iron core is released, providing a DC voltage source for the secondary circuit. The diode D is turned on, and the current of the secondary circuit flows through the diode D and the capacitor C. At this time, the end of the capacitor C connected to the diode D is the positive electrode of the capacitor C. In this case, when the switch K is closed, the voltage value of the negative pole of the photovoltaic module to the ground will be equal to the voltage value of the capacitor C. Furthermore, a positive voltage will exist between the negative pole of the photovoltaic module and the grounded metal frame, thereby raising the voltage of the negative pole of the photovoltaic module to the ground end to a positive voltage. In addition, it can be understood that in order to achieve the repair effect, the voltage value on the capacitor C needs to be higher than or equal to the absolute value of the negative voltage between the negative pole of the photovoltaic module and the grounded metal frame when the photovoltaic module is working during the day. However, due to the higher negative voltage between the negative terminal of the photovoltaic module and the grounded metal frame during daytime operation, the required voltage across capacitor C is higher, for example, greater than 300V. This results in a larger number of turns in winding L, which in turn leads to a larger transformer 130 and higher costs. Furthermore, the larger number of turns in winding L also results in poor electromagnetic interference (EMI) performance of transformer 130.

[0069] In an embodiment of the present application, when the voltage that the anti-potential induced attenuation circuit 100 needs to output is a fixed value, since a part of the voltage can be provided by the first energy storage element 122, compared with the solution in the related art in which the voltage on the capacitor is entirely provided by the voltage on the secondary winding L2, the voltage at the secondary winding L2 of the first switch element K1 in the primary circuit 110 when the first switch element K1 is disconnected can be reduced, and since the voltage on the secondary winding L2 is proportional to the number of turns of the secondary winding L2, therefore, since the voltage on the secondary winding L2 of the first switch element K1 in the primary circuit 110 in the disconnected state can be reduced, the number of turns of the secondary winding L2 can be reduced, thereby reducing the volume and cost of the anti-potential induced attenuation circuit 100, and improving the anti-electromagnetic interference capability of the transformer 130.

[0070] In some embodiments, optionally, when the first switch element K1 is in the on state, the third switch element 124 is on, and the second switch element 121 is off; when the first switch element K1 is in the off state, the second switch element 121 is on, and the third switch element 124 is off.

[0071] In this embodiment, the first switch K1 in the primary circuit 110 is controlled to be in an on state, and the primary winding L1 of the transformer 130 is in an energy storage state. At this time, the third switch 124 is in an on state, and the second switch 121 is in an off state. The second energy storage element 123 is charged through the second energy storage circuit, and the charging voltage is such that the first end of the first energy storage element 122 is a positive voltage and the second end of the first energy storage element 122 is a negative voltage. The first switch K1 in the primary circuit 110 is controlled to be in an off state, and the primary winding L1 of the transformer 130 releases the stored energy. At this time, the second switch 121 is in an on state, and the third switch 124 is in an off state. The first energy storage element 122 is charged through the first energy storage circuit, and the charging voltage is such that the first end of the second energy storage element 123 is a positive voltage and the second end of the second energy storage element 123 is a negative voltage.

[0072] Specifically, when the first switch K1 is in the on state, the current direction A of the secondary circuit 120 is as follows: Figure 3 When the first switch K1 is in the off state, the current direction B of the secondary circuit 120 is as shown in FIG. Figure 4 shown.

[0073] In an embodiment of the present application, the on-off state of the second switch element 121 and the third switch element 124 can automatically switch the on-off state in response to the on-off state of the first switch element K1, thereby adjusting the current flow direction in the secondary circuit 120, so that when the voltage required to be output by the anti-electromotive force induced attenuation circuit 100 is a fixed value, a part of the voltage can be provided by the first energy storage element 122, thereby reducing the number of turns of the secondary winding L2, thereby reducing the volume and cost of the transformer 130, and also improving the ability of the transformer 130 to resist electromagnetic interference.

[0074] like Figures 1 to 4 As shown, in some embodiments, optionally, the second switch element 121 includes a first diode D1, a first end of the first diode D1 is connected to the first end of the secondary winding L2, and a second end of the first diode D1 is connected to the negative pole PV- of the photovoltaic component 201; wherein, the first end to the second end of the first diode D1 is unidirectionally conductive.

[0075] In an embodiment of the present application, the second switching element 121 may be optionally a diode. Specifically, the first diode D1 is arranged as the second switching element 121 between the first end of the secondary winding L2 and the negative pole PV- of the photovoltaic component 201, and the second end of the first diode D1 is also connected to the first end of the first energy storage element 122.

[0076] Specifically, when the first switch K1 is in the off state, the current signal at the positive electrode of the secondary winding L2 is transmitted from the first end to the second end of the first diode D1. Since the first end to the second end of the first diode D1 is unidirectionally conductive, the first energy storage element 122 can be charged at this time.

[0077] In the embodiment of the present application, by setting the second switch element 121 as the first diode D1, and the first end to the second end of the first diode D1 is unidirectionally conductive, when the first switch element K1 is in the disconnected state, the first end of the secondary winding L2 serves as the positive electrode, and the second end of the secondary winding L2 serves as the negative electrode, so that the second switch element 121 can be in the on state, and the path between the secondary winding L2 and the first energy storage element 122 is in the on state, so that the first energy storage element 122 is charged when the first switch element K1 is disconnected.

[0078] like Figures 1 to 4 As shown, in some embodiments, optionally, the second switch element 121 includes a first diode D1, a first end of the first diode D1 is connected to the first end of the secondary winding L2, and a second end of the first diode D1 is connected to the negative pole PV- of the photovoltaic component 201; wherein, the first end to the second end of the first diode D1 is unidirectionally conductive.

[0079] In an embodiment of the present application, the third switching element 124 can be optionally a diode. Specifically, the second diode D2 is arranged as the third switching element 124 between the first end of the secondary winding L2 and the second end of the second energy storage element 123, and the first end of the second diode D2 is also connected to the ground terminal Pe of the photovoltaic component 201.

[0080] Specifically, when the first switch K1 is in the on state, the current signal at the positive electrode of the secondary winding L2 is transmitted from the first end to the second end of the second diode D2. Since the second diode D2 is unidirectionally conductive from the first end to the second end, the second energy storage element 123 can be charged at this time.

[0081] In the embodiment of the present application, by setting the third switch element 124 as the second diode D2, and the first end to the second end of the second diode D2 is unidirectionally conductive, when the first switch element K1 is in the on state, the second end of the secondary winding L2 serves as the positive electrode, and the first end of the secondary winding L2 serves as the negative electrode, so that the third switch element 124 can be in the on state, and the path between the secondary winding L2 and the first energy storage element 122 is in the on state, so that the first energy storage element 122 is charged when the first switch element K1 is disconnected.

[0082] like Figures 1 to 4 As shown, in some embodiments, optionally, the first energy storage element 122 includes: at least one first capacitor C1, the positive electrode of at least one first capacitor C1 is connected to the second end of the first switch element K1; the second energy storage element 123 includes: at least one second capacitor C2, the positive electrode of at least one second capacitor C2 is connected to the negative electrode of at least one first capacitor C1, and the negative electrode of at least one second capacitor C2 is connected to the ground terminal Pe of the photovoltaic component 201.

[0083] In the embodiment of the present application, the first energy storage element 122 may be provided with at least one first capacitor C1, and the second energy storage element 123 may be provided with at least one second capacitor C2. By using the first capacitor C1 and the second capacitor C2 as the first energy storage element 122 and the second energy storage element 123, respectively, the stability of energy storage can be ensured, thereby improving the effectiveness of the anti-potential induced degradation circuit 100 in repairing the photovoltaic module 201 from the potential induced effect.

[0084] It should be noted that the number of first capacitors C1 and second capacitors C2 is not limited, and when there are multiple first capacitors C1 or multiple second capacitors C2, the connection method between the multiple first capacitors C1 and the connection method between the multiple second capacitors C2 are also not limited.

[0085] Specifically, the positive electrode of the first capacitor C1 serves as the first end of the first energy storage element 122, and the negative electrode of the first capacitor C1 serves as the second end of the first energy storage element 122. The positive electrode of the second capacitor C2 serves as the first end of the second energy storage element 123, and the negative electrode of the second capacitor C2 serves as the second end of the second energy storage element 123.

[0086] like Figure 2 As shown, in some embodiments, optionally, the anti-potential induced degradation circuit 100 further includes:

[0087] The fourth switch element K4 has a first end connected to the first end of the first energy storage element 122 , and a second end connected to the negative electrode PV− of the photovoltaic assembly 201 .

[0088] In this embodiment, the anti-potential-induced degradation circuit 100 further includes a fourth switch element K4, which is disposed between the first energy storage element 122 and the negative electrode PV- of the photovoltaic module 201. When the fourth switch element K4 is in the on state, the anti-potential-induced degradation circuit 100 is connected to the photovoltaic module 201, and the anti-potential-induced degradation circuit 100 can compensate for the potential-induced degradation effect of the photovoltaic module 201. When the fourth switch element K4 is in the off state, the circuit between the anti-potential-induced degradation circuit 100 and the photovoltaic module 201 is disconnected, and the anti-potential-induced degradation circuit 100 has no effect on the photovoltaic module 201.

[0089] In the embodiment of the present application, a fourth switch element K4 is provided between the first end of the first energy storage element 122 and the photovoltaic module 201, so that the conduction state between the anti-potential induced decay circuit 100 and the photovoltaic module 201 can be controlled by controlling the on-off state of the fourth switch element K4, thereby improving the flexibility of circuit control.

[0090] like Figure 2 As shown, in some embodiments, optionally, the anti-electromotive force induced attenuation circuit 100 further includes: a controller 125, the controller 125 is connected to the control end of the first switch element K1 and the control end of the fourth switch element K4, and the controller 125 is used to control the first switch element K1 to switch between the on state and the off state according to a preset frequency when the fourth switch element K4 is in the on state.

[0091] In this embodiment, a controller 125 is further provided in the anti-potential induced attenuation circuit 100. The controller 125 is connected to the control end of the first switch element K1 and the control end of the fourth switch element K4. The controller 125 can control the on-off state of the first switch element K1 and the on-off state of the fourth switch element K4, thereby controlling the operation of the anti-potential induced attenuation circuit 100.

[0092] Specifically, when the anti-potential-induced degradation circuit 100 is required to repair the potential-induced degradation effect of the photovoltaic module 201, the controller 125 controls the fourth switch K4 to be in the on state, thereby connecting the anti-potential-induced degradation circuit 100 to the photovoltaic module 201. When the anti-potential-induced degradation circuit 100 is not required to repair the potential-induced degradation effect of the photovoltaic module 201, the controller 125 controls the fourth switch K4 to be in the off state, thereby disconnecting the anti-potential-induced degradation circuit 100 from the photovoltaic module 201.

[0093] When the fourth switch element K4 is in the on state, the controller 125 controls the first switch element K1 to alternately switch between the on state and the off state. When the first switch element K1 is in the on state, the primary winding L1 of the transformer 130 is in an energy storage state. At this time, the first end of the secondary winding L2 is a negative electrode, the second end of the secondary winding L2 is a positive electrode, the third switch element 124 is in the on state, and the second switch element 121 is in the off state. The second energy storage element 123 is charged through the second energy storage circuit, and the charging voltage is such that the first end of the first energy storage element 122 is a positive voltage and the second end of the first energy storage element 122 is a negative voltage. When the first switch K1 in the primary circuit 110 is controlled to be in the off state, the primary winding L1 of the transformer 130 releases the stored energy. At this time, the first end of the secondary winding L2 is the positive pole, the second end of the secondary winding L2 is the negative pole, the second switch 121 is in the on state, and the third switch 124 is in the off state. The first energy storage element 122 is charged through the first energy storage circuit, and the charging voltage is that the first end of the second energy storage element 123 is a positive voltage, and the second end of the second energy storage element 123 is a negative voltage.

[0094] In an embodiment of the present application, by setting a corresponding controller 125 in the anti-potential induced degradation circuit 100 and controlling the conduction state of the first switch element K1 and the fourth switch element K4 through the controller 125, the control of the anti-potential induced degradation circuit 100 to repair the potential induced degradation effect of the photovoltaic component 201 is achieved, thereby improving the controllability of the anti-potential induced degradation circuit 100.

[0095] like Figure 2 As shown, according to some embodiments of the present application, optionally, a photovoltaic power generation system 200 is provided, including: a photovoltaic module 201 and an anti-potential induced attenuation circuit 100, the anti-potential induced attenuation circuit 100 is the anti-potential induced attenuation circuit in any of the above embodiments, the anti-potential induced attenuation circuit 100 is connected to the photovoltaic module 201, and thus has all the beneficial technical effects of the anti-potential induced attenuation circuit 100 in any of the above embodiments, which will not be repeated here.

[0096] In some embodiments, optionally, the photovoltaic power generation system 200 further includes: an inverter circuit 202 , wherein the input end of the inverter circuit 202 is connected to the photovoltaic component 201 , and the output end of the inverter circuit 202 is connected to the anti-potential induced degradation circuit 100 .

[0097] In the embodiment of the present application, photovoltaic power generation system 200 includes photovoltaic modules 201. Photovoltaic modules 201 generate a DC voltage signal when exposed to light. This DC voltage signal is converted into an AC voltage signal by inverter circuit 202. The AC voltage signal outputted from the output terminal of inverter circuit 202 is converted into a DC voltage signal and then transmitted to the anti-potential induced attenuation circuit 100, thereby powering the primary circuit 110 of the anti-potential induced attenuation circuit 100.

[0098] Exemplarily, a rectifier circuit 204 is provided between the primary winding L1 and the inverter circuit 202 , and the rectifier circuit 204 converts the current electrical signal output by the inverter circuit 202 into a direct current electrical signal and transmits it to the primary winding L1 .

[0099] In some embodiments, optionally, the photovoltaic power generation system 200 further includes: a battery assembly 203 connected to the positive electrode PV+ of the photovoltaic assembly 201 and the negative electrode PV- of the photovoltaic assembly 201 .

[0100] In the embodiment of the present application, a battery assembly 203 is provided in the photovoltaic power generation system 200 , and the battery assembly 203 is used to store the electrical energy generated by the photovoltaic assembly 201 .

[0101] Exemplarily, the output end of the battery assembly 203 is connected to the inverter circuit 202 , and the battery assembly 203 can output an AC voltage signal to the outside through the inverter circuit 202 .

[0102] It should be clarified that in the claims, specification and drawings of this application, the term "plurality" refers to two or more. Unless otherwise clearly defined, the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the purpose of more conveniently describing this application and making the description process simpler, and is not intended to indicate or imply that the device or element referred to must have the specific orientation described, be constructed and operated in a specific orientation. Therefore, these descriptions cannot be understood as limitations on this application. The terms "connect", "install", "fix" and the like should be understood in a broad sense. For example, "connection" can be a fixed connection between multiple objects, or a detachable connection between multiple objects, or an integral connection; it can be a direct connection between multiple objects, or an indirect connection between multiple objects through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood based on the specific circumstances of the above data.

[0103] In the claims, specification, and drawings of this application, the terms "some embodiments," "some embodiments," "specific embodiments," etc., mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least some of the embodiments or examples of this application. In the claims, specification, and drawings of this application, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0104] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A circuit for resisting potential induced degradation, characterized in that: Applied to photovoltaic modules, the anti-potential induced degradation circuit includes: a primary circuit, the primary circuit comprising a first switching element and a primary winding of a transformer, a first end of the primary winding being connected to a positive electrode of a power supply, a second end of the primary winding being connected to a first end of the first switching element, and a second end of the first switching element being connected to a negative electrode of the power supply; A secondary circuit, the secondary circuit comprising: The secondary winding of the transformer is coupled to the primary winding; a second switch element, wherein a first end of the second switch element is connected to a first end of the secondary winding; a first energy storage element, wherein a first end of the first energy storage element is connected to the second end of the second switch element, and a first end of the first energy storage element is connected to the negative electrode of the photovoltaic module; a second energy storage element, wherein a first end of the second energy storage element is connected to the second end of the first energy storage element, a first end of the second energy storage element is connected to the second end of the secondary winding, and a second end of the second energy storage element is connected to a ground terminal of the photovoltaic module; a third switch element, wherein a first end of the third switch element is connected to the second end of the second energy storage element, and a second end of the third switch element is connected to the first end of the secondary winding.

2. The anti-potential induced degradation circuit according to claim 1, characterized in that: The first switch is in a conducting state, the third switch is conducting, and the second switch is off; The first switch element is in an off state, the second switch element is turned on, and the third switch element is turned off.

3. The anti-potential induced degradation circuit according to claim 1, characterized in that: The second switch element includes a first diode, a first end of the first diode is connected to the first end of the secondary winding, and a second end of the first diode is connected to the negative electrode of the photovoltaic module; Wherein, the first diode is unidirectionally conducted from the first end to the second end.

4. The anti-potential induced degradation circuit according to claim 1, characterized in that: The third switch element includes a second diode, a first end of the second diode is connected to the second end of the second energy storage element, and a second end of the second diode is connected to the first end of the secondary winding; The first end and the second end of the second diode are unidirectionally conductive.

5. The circuit for resisting potential induced degradation according to claim 1, wherein: The first energy storage element comprises: at least one first capacitor, wherein a positive electrode of the at least one first capacitor is connected to the second end of the first switch; The second energy storage element includes: At least one second capacitor, wherein a positive electrode of the at least one second capacitor is connected to a negative electrode of the at least one first capacitor, and a negative electrode of the at least one second capacitor is connected to a ground terminal of the photovoltaic module.

6. The circuit for resisting potential induced degradation according to any one of claims 1 to 5, characterized in that: Also includes: A fourth switch element, wherein a first end of the fourth switch element is connected to the first end of the first energy storage element, and a second end of the fourth switch element is connected to the negative electrode of the photovoltaic assembly.

7. The circuit for resisting potential induced degradation according to claim 6, wherein: Also includes: A controller is connected to the control end of the first switch element and the control end of the fourth switch element, and is used to control the first switch element to switch between the on state and the off state according to a preset frequency when the fourth switch element is in the on state.

8. A photovoltaic power generation system, characterized in that: include: Photovoltaic panels; The anti-potential induced degradation circuit according to any one of claims 1 to 7 is connected to the photovoltaic module.

9. The photovoltaic power generation system according to claim 8, characterized in that: Also includes: An inverter circuit, wherein the input end of the inverter circuit is connected to the photovoltaic component, and the output end of the inverter circuit is connected to the anti-electromotive force induced attenuation circuit.

10. The photovoltaic power generation system according to claim 8 or 9, characterized in that: Also includes: The battery assembly is connected to the positive electrode of the photovoltaic assembly and the negative electrode of the photovoltaic assembly.

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