PID effect repairing device of photovoltaic inverter and photovoltaic inverter

Abstract

The utility model discloses a photovoltaic inverter's PID effect repair device and photovoltaic inverter, the PID effect repair device has input terminal and output terminal, the input terminal is configured to connect the power grid to take power from the power grid input terminal, one end of the output terminal is configured to connect the photovoltaic panel or the DC side of the photovoltaic inverter, and the other end of the output terminal is configured to connect the photovoltaic panel or the DC side of the photovoltaic inverter. The other end of the output end is grounded; the PID effect repairing device comprises an isolation capacitor and a rectification module, the isolation capacitor is connected between the input end and the rectification module, and the output end is connected to the rectification module. The PID effect repairing device provided by the utility model greatly reduces the repairing cost and complexity.

Description

Technical Field

[0001] The utility model belongs to the technical field of electronic power, and in particular relates to a PID effect repair device for a photovoltaic inverter and the photovoltaic inverter. Background Art

[0002] To reduce the cost of photovoltaic systems and increase their power generation, photovoltaic cell voltage configurations are becoming increasingly higher, with high-voltage photovoltaic systems gradually becoming the mainstream in the market. However, this increase in system voltage can cause the photovoltaic cells to experience a high positive or negative bias relative to the ground. This can lead to severe PID (Protection Path Interference) effects in the photovoltaic modules contained within these cells, particularly under extreme conditions such as high temperature and high humidity. The PID effect occurs when the negative electrode of a P-type photovoltaic panel is subjected to a negative voltage relative to the ground, or the positive electrode of an N-type photovoltaic panel is subjected to a positive voltage relative to the ground. This leads to leakage current between the glass and the encapsulation material, causing a large amount of charge to accumulate on the cell surface, deteriorating the cell passivation effect and ultimately causing degradation of the photovoltaic module performance. The PID effect can directly lead to a decrease in the power generation of a photovoltaic power station, thereby affecting the power generation revenue.

[0003] However, the PID effect is reversible. By applying a reverse voltage during the PV module's non-operating period, the attenuation characteristics of the PV module caused by the PID effect can be restored. Traditional reverse voltage repair is typically achieved using an isolation transformer, such as in flyback, forward, and push-pull switching power supplies. The use of an isolation transformer results in larger circuits and higher costs. Utility Model Content

[0004] In order to solve the above technical problems, the utility model provides a PID effect repair device and a photovoltaic inverter, which greatly reduce the repair cost and complexity.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A PID effect repair device for a photovoltaic inverter, the PID effect repair device having an input end and an output end, the input end being configured to be connected to a power grid to draw power from the power grid, one end of the output end being configured to be connected to a photovoltaic panel or a DC side of the photovoltaic inverter, and the other end of the output end being grounded;

[0007] The PID effect repair device includes an isolation capacitor and a rectifier module. The isolation capacitor is connected between the input end and the rectifier module, and the output end is connected to the rectifier module.

[0008] In a preferred embodiment, the PID effect repair device further includes a filtering module, and the filtering module is arranged between the output end and the rectifier module.

[0009] In a preferred embodiment, the filtering module includes a filtering capacitor, the rectifying module includes a plurality of rectifier bridges connected in parallel, and the filtering capacitor is connected in parallel to both sides of the rectifier bridges.

[0010] In a preferred embodiment, the filtering module includes a resistor connected in parallel with the filtering capacitor.

[0011] In a preferred embodiment, the rectifier module includes a plurality of rectifier bridges connected in parallel, each of the rectifier bridges includes a plurality of rectifier diodes connected in series, and a connection point of the plurality of rectifier diodes of each rectifier bridge is connected to one of the input terminals.

[0012] In a preferred embodiment, the number of the rectifier bridges is two, wherein one of the rectifier bridges is connected to one phase of the power grid via one of the input terminals, and the other rectifier bridge is connected to the other phase of the power grid via the other input terminal;

[0013] Alternatively, the number of the rectifier bridges is three, the first rectifier bridge is connected to the U phase of the three-phase power grid through the first input end, the second rectifier bridge is connected to the V phase of the three-phase power grid through the second input end, and the third rectifier bridge is connected to the W phase of the three-phase power grid through the third input end.

[0014] In a preferred embodiment, the PID effect repair device further includes a switch for controlling the on / off of the output end.

[0015] In a preferred embodiment, the photovoltaic inverter is configured to be connected to a P-type photovoltaic module, and the first end of the output end is configured to be connected to the negative output terminal of the DC / DC conversion module of the photovoltaic inverter.

[0016] In a preferred embodiment, the photovoltaic inverter is configured to be connected to an N-type photovoltaic module, the first end of the output end is grounded, and the second end of the output end is configured to be connected to the positive output end of the DC / DC conversion module of the photovoltaic inverter.

[0017] In a preferred embodiment, the photovoltaic inverter is configured to be able to connect to P-type and N-type photovoltaic modules, the first end of the output end is connected to the first output branch and the second output branch, the first output branch is configured to be connected to the negative output terminal of the DC / DC conversion module of the photovoltaic inverter, and the second output branch is configured to be grounded; the second end of the output end is connected to the third output branch and the fourth output branch, the third output branch is configured to be connected to the positive output terminal of the DC / DC conversion module of the photovoltaic inverter, and the fourth output branch is configured to be grounded; the first output branch, the second output branch, the third output branch and the fourth output branch respectively include switches for controlling the on and off of their respective branches.

[0018] This embodiment also adopts the following technical solutions:

[0019] A photovoltaic inverter comprises the above-mentioned PID effect repair device.

[0020] The present invention adopts the above solution, which has the following advantages compared with the prior art:

[0021] The PID effect repair device of the present invention obtains power from the power grid at its input end, obtains a DC repair power supply through an isolation capacitor and a rectifier module, and connects one end of the output end of the repair power supply to a photovoltaic inverter and the other end to ground. The PID effect repair device has a simple structure, lower cost, and smaller size, which greatly reduces the repair cost and complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 Schematic diagram of a PID effect repair device according to Example 1 of the present invention, wherein the photovoltaic module is a P-type photovoltaic module;

[0024] Figure 2 Schematic diagram of a PID effect repair device according to Example 2 of the present utility model, wherein the photovoltaic module is an N-type photovoltaic module;

[0025] Figure 3 Schematic diagram of a PID effect repair device according to Example 3 of the present utility model, wherein the photovoltaic module is a P-type photovoltaic module;

[0026] Figure 4 Schematic diagram of a PID effect repair device according to Example 4 of the present utility model, wherein the photovoltaic module is an N-type photovoltaic module;

[0027] Figure 5 Schematic diagram of a PID effect repair device according to Example 5 of the present utility model, wherein the photovoltaic module is a P-type photovoltaic module;

[0028] Figure 6 Schematic diagram of a PID effect repair device according to Example 6 of the present utility model, wherein the photovoltaic module is an N-type photovoltaic module;

[0029] Figure 7 Schematic diagram of a PID effect repair device according to Example 7 of the present utility model, wherein the photovoltaic modules are P-type and N-type photovoltaic modules.

[0030] in,

[0031] 100, input end; 200, output end; 300, photovoltaic inverter;

[0032] 2. First output branch; 3. Second output branch; 4. Third output branch; 5. Fourth output branch; 6. Power grid; 7. Photovoltaic module. DETAILED DESCRIPTION

[0033] The following describes in detail preferred embodiments of the present invention in conjunction with the accompanying drawings to make the advantages and features of the present invention more easily understood by those skilled in the art. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0034] Example 1

[0035] Reference Figure 1 As shown, this embodiment provides a photovoltaic inverter, which includes a PID effect repair device.

[0036] Furthermore, the PID effect repair device has an input terminal 100 and an output terminal 200. The input terminal 100 is configured to be connected to the grid 6 to draw power from the grid 6. One end of the output terminal 200 is configured to be connected to the DC side of the photovoltaic panel or photovoltaic inverter 300, and the other end of the output terminal 200 is grounded to PE. Specifically, in this embodiment, the photovoltaic inverter is configured to be connected to a P-type photovoltaic module. The first end of the output terminal 200 is configured to be connected to the negative output terminal of the photovoltaic inverter's DC / DC converter module, and the second end of the output terminal 200 is grounded to PE. The DC / DC converter module is a DC voltage conversion module, specifically a BOOST circuit. The rear end of the BOOST circuit is connected to the INV circuit, and the IVN circuit is connected to the grid 6.

[0037] The PID effect repair device includes an isolation capacitor C1, a rectifier module, a filter module, and switches K1 and K2 for controlling the on / off of the output terminal, wherein the switches K1 and K2 can be relays, transistors, MOSFETs, etc. Specifically, in this embodiment, the switches K1 and K2 are relays, and the control terminal of the relay is electrically connected to the DC side of the photovoltaic inverter. To avoid the instantaneous impact current of the relay closing being too large and affecting the life of the relay, a current limiting resistor can be added between the relay and the photovoltaic inverter and / or the relay and PE. The isolation capacitor C1 is connected between the input terminal 100 and the rectifier module, the output terminal 200 is connected to the rectifier module, and the filter module is arranged between the output terminal 200 and the rectifier module. The filter module includes a filter capacitor C2. In addition to isolating the power grid 6 from the output terminal 200, the isolation capacitor C1 can also prevent the system from short-circuiting due to two grounding points when the photovoltaic module is repaired.

[0038] Considering the parasitic capacitance between the PV+ and PV- modules and the PE, filter capacitor C2 can be omitted to further reduce the cost of the repair device. In other embodiments, a current-limiting resistor can be added to the circuit before isolation capacitor C1 to prevent overcurrent from damaging the device during abnormal operating conditions such as power-on transients and surges.

[0039] Furthermore, the rectifier module includes a plurality of rectifier bridges connected in parallel, each rectifier bridge includes a plurality of rectifier diodes connected in series, and the connection point of the plurality of rectifier diodes of each rectifier bridge is connected to an input terminal 100. The filter capacitor C2 is connected in parallel to both sides of the rectifier bridge. Furthermore, the rectifier bridge is composed of at least two rectifier diodes connected in series, the midpoint of the two rectifier diodes is connected to the input terminal 100, the positive pole of the rectifier diode D1 is grounded PE, and the negative pole is connected to the negative pole of the output terminal of the DC / DC conversion module of the photovoltaic inverter. More specifically, there are two rectifier bridges, one of which is connected to one phase of the power grid 6 through an input terminal, and the rectifier bridge has two diodes D1, and the other rectifier bridge is connected to the other phase of the power grid 6 through another input terminal, and the rectifier bridge has two diodes D2.

[0040] In this embodiment, during the non-operating hours of a P-type PV module, PV module repair is initiated by closing switches K1 and K2. The repair device's input terminal 100 draws power from any two phases of the grid 6. Isolation capacitor C1 isolates the grid side from output terminal 200, then passes through a rectifier bridge to generate a pulsating DC power supply. Finally, filter capacitor C2 generates a stable, isolated DC repair power supply.

[0041] The repair device of this embodiment is composed of an isolation capacitor C1, a rectifier module, a filter capacitor C2, and a switch, which can greatly reduce the cost and complexity of the repair device. In situations where the repair voltage requirement is not high, only any two phases of the power grid are required as input.

[0042] Example 2

[0043] Reference Figure 2 As shown, this embodiment is basically the same as Example 1, except that the photovoltaic inverter of this embodiment is configured to connect to an N-type photovoltaic module. The first end of the output terminal 200 is connected to ground PE, and the second end of the output terminal 200 is configured to connect to the positive output terminal of the DC / DC converter module of the photovoltaic inverter. Each rectifier bridge consists of two rectifier diodes D1 connected in series. The midpoint between the two rectifier diodes D1 is connected to the input terminal 100. The positive electrode of the rectifier diode D1 is connected to the positive output terminal of the DC / DC converter module of the photovoltaic inverter, and the negative electrode is connected to ground PE.

[0044] Example 3

[0045] Reference Figure 3 As shown, this embodiment is basically the same as embodiment 1, except that the filtering module further includes a resistor R1 connected in parallel with the filter capacitor C2, and the voltage output by the output terminal 200 is directly related to R1. The output voltage can be adjusted by controlling the size of the resistor R1.

[0046] Example 4

[0047] Reference Figure 4 As shown, this embodiment is basically the same as embodiment 2, except that the filtering module further includes a resistor R1 connected in parallel with the filter capacitor C2, and the voltage output by the output terminal 200 is directly related to R1. The output voltage can be adjusted by controlling the size of the resistor R1.

[0048] Example 5

[0049] Reference Figure 5 As shown, this embodiment is basically the same as Example 1, except that in order to further expand the voltage output upper limit of the output terminal 200, the input terminal can be adjusted from any two-phase input of the power grid to a three-phase input. The number of rectifier bridges is three, the first rectifier bridge is connected to the U phase of the three-phase power grid through the first input terminal, the second rectifier bridge is connected to the V phase of the three-phase power grid through the second input terminal, and the third rectifier bridge is connected to the W phase of the three-phase power grid through the third input terminal. Furthermore, the first rectifier bridge is connected in series with two rectifier diodes D1, the second rectifier bridge is connected in series with two rectifier diodes D2, and the third rectifier bridge is connected in series with two rectifier diodes D3. The positive poles of the rectifier diodes D1, D2 and D3 are grounded, and the negative poles are connected to the negative pole of the output terminal of the DC / DC conversion module of the photovoltaic inverter. When the three-phase voltage is input, the voltage output by the output terminal 200 can also be adjusted by connecting a resistor R1 in parallel with the filter capacitor C2.

[0050] Example 6

[0051] Reference Figure 6As shown, this embodiment is basically the same as Example 2, except that the number of rectifier bridges is three, the first rectifier bridge is connected to the U phase of the three-phase power grid through the first input terminal, the second rectifier bridge is connected to the V phase of the three-phase power grid through the second input terminal, and the third rectifier bridge is connected to the W phase of the three-phase power grid through the third input terminal. Furthermore, the first rectifier bridge is connected in series with two rectifier diodes D1, the second rectifier bridge is connected in series with two rectifier diodes D2, and the third rectifier bridge is connected in series with two rectifier diodes D3. The positive poles of the rectifier diodes D1, D2, and D3 are connected to the positive pole of the output terminal of the DC / DC conversion module of the photovoltaic inverter, and the negative poles are grounded to PE. When the three-phase voltage is input, the voltage output by the output terminal 200 can also be adjusted by connecting a resistor R1 in parallel at the filter capacitor C2.

[0052] Example 7

[0053] Reference Figure 7 As shown, the photovoltaic inverter of this embodiment is configured to be able to connect to P-type and N-type photovoltaic modules. The first end of the output terminal 200 is connected to the first output branch 2 and the second output branch 3. The first output branch 2 is configured to be connected to the negative output terminal of the DC / DC conversion module of the photovoltaic inverter, and the second output branch 3 is configured to be grounded; the second end of the output terminal 200 is connected to the third output branch 4 and the fourth output branch 5. The third output branch 4 is configured to be connected to the positive output terminal of the DC / DC conversion module of the photovoltaic inverter, and the fourth output branch 5 is configured to be grounded PE; the first output branch 2, the second output branch 3, the third output branch 4 and the fourth output branch 5 respectively include switches for controlling the on / off of their respective branches. Specifically, the first output branch 2 includes a switch K1, the second output branch 3 includes a switch K2, the third output branch 4 includes a switch K3, and the fourth output branch 5 includes a switch K4. The actual product may integrate the free selection function of P-type and N-type photovoltaic module PID effect repair, which can be switched through switches K1, K2, K3 and K4. In this embodiment, the resistor R1 can also be connected in parallel with the filter capacitor C2 to adjust the output voltage.

[0054] As used in this specification and claims, the terms "comprises" and "include" merely indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list; a method or apparatus may also include other steps or elements. The term "and / or" as used herein includes any combination of one or more of the associated listed items.

[0055] It should be noted that, unless otherwise specified, when a feature is referred to as being "fixed" or "connected" to another feature, it may be directly fixed or connected to the other feature or indirectly fixed or connected to the other feature. In addition, the terms "upper," "lower," "left," and "right" used in this utility model are only used with respect to the relative positions of the components of the utility model in the accompanying drawings.

[0056] The above embodiment is intended only to illustrate the technical concept and features of the present invention and is a preferred embodiment. Its purpose is to enable those familiar with the art to understand the content of the present invention and implement it accordingly. It is not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A PID effect repair device for a photovoltaic inverter, characterized in that: The PID effect repair device has an input end and an output end, the input end is configured to be connected to a power grid to draw power from the power grid, one end of the output end is configured to be connected to a photovoltaic panel or a DC side of the photovoltaic inverter, and the other end of the output end is grounded; The PID effect repair device includes an isolation capacitor and a rectifier module. The isolation capacitor is connected between the input end and the rectifier module, and the output end is connected to the rectifier module.

2. The PID effect repair device according to claim 1, characterized in that: The PID effect repair device further includes a filtering module, which is arranged between the output end and the rectifier module.

3. The PID effect repair device according to claim 2, characterized in that: The filtering module includes a filtering capacitor, the rectifying module includes a plurality of rectifier bridges connected in parallel, and the filtering capacitor is connected in parallel to both sides of the rectifier bridges.

4. The PID effect repair device according to claim 3, characterized in that: The filter module includes a resistor connected in parallel with the filter capacitor.

5. The PID effect repair device according to claim 1, characterized in that: The rectifier module includes a plurality of rectifier bridges connected in parallel, each of the rectifier bridges includes a plurality of rectifier diodes connected in series, and a connection point of the plurality of rectifier diodes of each rectifier bridge is connected to one of the input ends.

6. The PID effect repair device according to claim 5, characterized in that: There are two rectifier bridges, one of which is connected to one phase of the power grid via one input terminal, and the other rectifier bridge is connected to the other phase of the power grid via the other input terminal; Alternatively, the number of the rectifier bridges is three, the first rectifier bridge is connected to the U phase of the three-phase power grid through the first input end, the second rectifier bridge is connected to the V phase of the three-phase power grid through the second input end, and the third rectifier bridge is connected to the W phase of the three-phase power grid through the third input end.

7. The PID effect repair device according to claim 1, characterized in that: The PID effect repair device further includes a switch for controlling the on and off of the output end.

8. The PID effect repair device according to claim 1, characterized in that: The photovoltaic inverter is configured to be connected to a P-type photovoltaic module, and the first end of the output end is configured to be connected to the negative output end of the DC / DC conversion module of the photovoltaic inverter.

9. The PID effect repair device according to claim 1, characterized in that: The photovoltaic inverter is configured to be connected to an N-type photovoltaic module, a first end of the output end is grounded, and a second end of the output end is configured to be connected to a positive output terminal of a DC / DC conversion module of the photovoltaic inverter.

10. The PID effect repair device according to claim 1, characterized in that: The photovoltaic inverter is configured to be able to connect to P-type and N-type photovoltaic modules. The first end of the output end is connected to the first output branch and the second output branch. The first output branch is configured to be connected to the negative output terminal of the DC / DC conversion module of the photovoltaic inverter, and the second output branch is configured to be grounded. The second end of the output end is connected to the third output branch and the fourth output branch. The third output branch is configured to be connected to the positive output terminal of the DC / DC conversion module of the photovoltaic inverter, and the fourth output branch is configured to be grounded. The first output branch, the second output branch, the third output branch, and the fourth output branch respectively include switches for controlling the on and off of their respective branches.

11. A photovoltaic inverter, characterized in that: The device comprises the PID effect repair device according to any one of claims 1 to 10.

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