Inverter, power conversion circuit and photovoltaic system

Abstract

The invention discloses an inverter, a power conversion circuit and a photovoltaic system. The inverter comprises a booster circuit, a direct current bus and an inverter circuit, the boost circuit comprises a first power switch tube, a first positive electrode circuit and a first negative electrode circuit, the first positive electrode circuit comprises a first positive electrode input end, a first boost diode and a first boost inductor, the first negative electrode circuit comprises a first anti-reverse module, and input ends of the boost circuit comprise a first positive electrode input end and a first negative electrode input end; the direct-current bus comprises a bus capacitor; the first negative electrode input end is connected with one end of the first anti-reverse module, the other end of the first anti-reverse module is connected with the negative electrode end of the bus capacitor, and the first anti-reverse module comprises a first anti-reverse switch and a first anti-reverse diode which are connected in parallel. According to the embodiment of the invention, the power device can be effectively protected under the condition that the branch inputs are all reversely connected.

Description

Technical Field

[0001] The present application relates to telecommunication technology, which is applied to the fields of photovoltaic power generation, energy, etc., and in particular to an inverter, a power conversion circuit and a photovoltaic system. Background Art

[0002] When the photovoltaic (PV) input of the current photovoltaic inverter is reversely connected, for the two-stage conversion inverter, the first stage is the boost circuit. At this time, the photovoltaic panel input is approximately short-circuited through the body diode of the insulated gate bipolar transistor (IGBT) or metal-oxide-semiconductor field-effect transistor (MOSFET) on the boost side. The short-circuit current Isc of the photovoltaic panel flows through the body diode of the power semiconductor, which will cause large losses and affect the reliable operation of the semiconductor device. Therefore, when selecting power semiconductors, it is necessary to pay attention to the forward voltage of its body diode not being too large, which limits the use of silicon carbide devices SiCMOSFET on the boost side (SiC MOSFET devices have a large parasitic body diode voltage drop).

[0003] In the existing solution, a two-stage topology is used for the inverter, and the first stage uses a boost circuit. In the scenario where the power switch tube uses SiC MOSFET, the normal operation of the detection unit and the protection unit requires the inverter's internal auxiliary source to start. If the inverter has two photovoltaic panel inputs, when only one branch is reversed, the system's internal auxiliary source can work and the detection function can work normally. If both branches are reversely connected, the system's internal auxiliary source cannot start normally, the detection function cannot work normally, and reverse polarity protection cannot be implemented.

[0004] Therefore, how to effectively protect the power devices when the branch inputs are all reversely connected is an issue that needs to be solved urgently. Summary of the invention

[0005] The embodiments of the present application provide an inverter, a power conversion circuit and a photovoltaic system, which can effectively protect the power switch tube even when all branch inputs are reversely connected.

[0006] In a first aspect, an embodiment of the present application provides an inverter, the inverter comprising a boost circuit, a DC bus and an inverter circuit;

[0007] The input end of the boost circuit is connected to the input end of the inverter, the output end of the boost circuit is connected to the DC bus, the input end of the inverter circuit is connected to the DC bus, and the output end of the inverter circuit is connected to the output end of the inverter;

[0008] The boost circuit includes a first power switch tube, a first positive circuit and a first negative circuit, the first positive circuit includes a first positive input terminal, a first boost diode and a first boost inductor, the first negative circuit includes a first anti-reverse module, and the input terminal of the boost circuit includes a first positive input terminal and a first negative input terminal;

[0009] The DC bus includes a bus capacitor;

[0010] The first positive input terminal is connected to one end of the first boost inductor, the other end of the first boost inductor is connected to one end of the first boost diode, the other end of the first boost diode is connected to the positive end of the bus capacitor, the first negative input terminal is connected to one end of the first anti-reverse module, the other end of the first anti-reverse module is connected to the negative end of the bus capacitor, one end of the first power switch tube is connected between the first boost inductor and the first boost diode, the other end of the first power switch tube is connected between the other end of the first anti-reverse module and the negative end of the bus capacitor, and the first anti-reverse module includes a first anti-reverse switch and a first anti-reverse diode connected in parallel.

[0011] In the embodiment of the present application, the added anti-reverse module not only has a simple structure, but also can effectively protect the power switch tube regardless of whether the input is connected in a positive and reverse connection or both are reversed, thereby effectively solving the reliability problem of the power semiconductor when the photovoltaic input polarity is reversed.

[0012] In a possible implementation, the boost circuit includes a second power switch tube and a second positive circuit, and the input end of the boost circuit includes a second positive input end; the second positive circuit includes a second boost diode and a second boost inductor, the second positive input end is connected to one end of the second boost inductor, the other end of the second boost inductor is connected to one end of the second boost diode, the other end of the second boost diode is connected to the positive end of the bus capacitor, one end of the second power switch tube is connected between the second boost inductor and the second boost diode, and the other end of the second power switch tube is connected between the other end of the first anti-reverse module and the negative end of the bus capacitor.

[0013] In the embodiment of the present application, taking two BST inputs as an example, in the scenario where the first negative input terminal is combined, the anti-reverse module is directly connected in series to the negative input terminal after the combination, which can achieve protection for the scenarios of reverse connection of BST1, reverse connection of BST2, and reverse connection of both BST1 and BST2.

[0014] In another possible implementation, the boost circuit includes a third power switch tube, a third positive circuit and a third negative circuit, the input end of the boost circuit includes a third positive input end and a third negative input end; the third positive circuit includes a third boost diode and a third boost inductor, the third positive input end is connected to one end of the third boost inductor, the other end of the third boost inductor is connected to one end of the third boost diode, and the other end of the boost diode is connected to the positive end of the bus capacitor; the third negative circuit includes a second anti-reverse module, the third negative input end is connected to one end of the second anti-reverse module, the second anti-reverse module is connected to the negative end of the bus capacitor, one end of the third power switch tube is connected between the third boost inductor and the third boost diode, the other end of the third power switch tube is connected between the other end of the second anti-reverse module and the negative end of the bus capacitor, and the second anti-reverse module includes a second anti-reverse switch and a second anti-reverse diode connected in parallel.

[0015] In the embodiment of the present application, taking two BST inputs as an example, in the scenario where the positive input terminal is not connected in series, the first anti-reverse module and the second anti-reverse module are respectively connected in series to different negative input terminals, which can achieve protection for the scenarios of BST1 reverse connection, BST2 reverse connection, and both BST1 and BST2 reverse connection.

[0016] In another possible implementation, the inverter includes a first auxiliary power supply and a first controller, the bus capacitor is used to charge the first auxiliary power supply, and the first auxiliary power supply is used to power the first controller;

[0017] The first controller is used to control the first anti-reverse switch to close when the voltage difference between the first positive input terminal and the first negative input terminal is positive, or,

[0018] The first controller is used to control the first anti-reverse switch to close when the current value of the first positive input terminal or the first negative input terminal is positive.

[0019] In this solution, the control logic when there is only one input is reflected.

[0020] In another possible implementation, the inverter includes a second auxiliary power supply and a second controller, the bus capacitor is used to charge the second auxiliary power supply, and the second auxiliary power supply is used to power the second controller;

[0021] The second controller is used to control the first anti-reverse switch to close when the voltage difference between the first positive input terminal and the first negative input terminal is positive and the voltage difference between the second positive input terminal and the first negative input terminal is positive, or,

[0022] The second controller is used to control the first anti-reverse switch to close when the current value of the first positive input terminal and the current value of the second positive input terminal are both positive.

[0023] In this solution, the control logic when there are two inputs and the inputs are combined is reflected.

[0024] In another possible implementation, the inverter includes a third auxiliary power supply and a third controller, the bus capacitor is used to charge the third auxiliary power supply, and the third auxiliary power supply is used to power the third controller;

[0025] The third controller is used to control the second anti-reverse switch to close when the voltage difference between the third positive input terminal and the third negative input terminal is positive, or,

[0026] The third controller is used to control the second anti-reverse switch to close when the current value of the third positive input terminal or the third negative input terminal is positive.

[0027] In this solution, the control logic when there are two inputs and the inputs are not combined is reflected.

[0028] In yet another possible implementation, the first anti-reverse switch is a normally open switch.

[0029] In yet another possible implementation, the second anti-reverse switch is the normally open switch.

[0030] In a second aspect, an embodiment of the present application further provides a power conversion circuit, the power conversion circuit comprising a first power switch tube, a first positive circuit, a first negative circuit and a DC bus; the first positive circuit comprises a first boost diode and a first boost inductor, the first negative circuit comprises a first anti-reverse module, and the input end of the power conversion circuit comprises a first positive input end and a first negative input end;

[0031] The DC bus includes a bus capacitor;

[0032] The first positive input terminal is connected to one end of the first boost inductor, the other end of the first boost inductor is connected to one end of the first boost diode, the other end of the first boost diode is connected to the positive end of the bus capacitor, the first negative input terminal is connected to one end of the first anti-reverse module, the other end of the first anti-reverse module is connected to the negative end of the bus capacitor, one end of the first power switch tube is connected between the first boost inductor and the first boost diode, the other end of the first power switch tube is connected between the other end of the first anti-reverse module and the negative end of the bus capacitor, and the first anti-reverse module includes a first anti-reverse switch and a first anti-reverse diode connected in parallel.

[0033] In a possible implementation, the power conversion circuit includes a second power switch tube and a second positive circuit, and the input end of the power conversion circuit includes a second positive input end; the second positive circuit includes a second boost diode and a second boost inductor, the second positive input end is connected to one end of the second boost inductor, the other end of the second boost inductor is connected to one end of the second boost diode, the other end of the second boost diode is connected to the positive end of the bus capacitor, one end of the second power switch tube is connected between the second boost inductor and the second boost diode, and the other end of the second power switch tube is connected between the other end of the first anti-reverse module and the negative end of the bus capacitor.

[0034] In another possible implementation, the power conversion circuit includes a third power switch tube, a third positive circuit and a third negative circuit, and the input end of the power conversion circuit includes a third positive input end and a third negative input end; the third positive circuit includes a third boost diode and a third boost inductor, the third positive input end is connected to one end of the third boost inductor, the other end of the third boost inductor is connected to one end of the third boost diode, and the other end of the boost diode is connected to the positive end of the bus capacitor; the third negative circuit includes a second anti-reverse module, the third negative input end is connected to one end of the second anti-reverse module, the second anti-reverse module is connected to the negative end of the bus capacitor, one end of the third power switch tube is connected between the third boost inductor and the third boost diode, the other end of the third power switch tube is connected between the other end of the second anti-reverse module and the negative end of the bus capacitor, and the second anti-reverse module includes a second anti-reverse switch and a second anti-reverse diode connected in parallel.

[0035] In another possible implementation manner, the first anti-reverse switch is used to close when the voltage difference between the first positive input terminal and the first negative input terminal is positive, or,

[0036] The first anti-reverse switch is further configured to be closed when the current value at the first positive input terminal or the first negative input terminal is positive.

[0037] In another possible implementation manner, the first anti-reverse switch is used to close when the voltage difference between the first positive input terminal and the first negative input terminal is positive and the voltage difference between the second positive input terminal and the first negative input terminal is positive, or,

[0038] The first anti-reverse switch is further configured to close when the current value at the first positive input terminal and the current value at the second positive input terminal are both positive.

[0039] In another possible implementation manner, the second anti-reverse switch is used to close when the voltage difference between the third positive input terminal and the third negative input terminal is positive, or,

[0040] The second anti-reverse switch is further configured to close when the current value at the third positive input terminal or the third negative input terminal is positive.

[0041] In yet another possible implementation, the first anti-reverse switch is a normally open switch.

[0042] In yet another possible implementation, the second anti-reverse switch is the normally open switch.

[0043] In a third aspect, the present application provides a photovoltaic system, comprising the inverter and photovoltaic module described in any one of the first aspects, wherein the input end of the inverter is connected to the photovoltaic module, the output end of the inverter is used to connect to a power grid, and the inverter is used to convert the direct current output by the photovoltaic module into alternating current and output it to the load, which may be a power grid, household electrical equipment, industrial electrical equipment, etc.

[0044] The beneficial effects of the technical solutions provided in the second to third aspects of the present application can refer to the beneficial effects of the technical solution of the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of an application scenario and internal structure of an inverter provided in an embodiment of the present application;

[0046] Figure 2 An example of an internal structure diagram of a positive input connection is shown;

[0047] Figure 3 An example of an internal structure schematic diagram in which both inputs are positively connected is shown;

[0048] Figure 4 An example of an internal structure diagram of two photovoltaic panels with either input connected in reverse;

[0049] Figure 5 An example of an internal structure schematic diagram in which both photovoltaic panel inputs are reversely connected is shown;

[0050] Figure 6 is a schematic diagram of the internal structure of a boost circuit 110 provided in an embodiment of the present application;

[0051] Figure 7 1 is a schematic diagram of the internal structure of a boost circuit 110 when two inputs are combined, provided in an embodiment of the present application;

[0052] Figure 81 is a schematic diagram of the internal structure of a boost circuit 110 when two inputs are not combined, provided in an embodiment of the present application;

[0053] Fig. 9 is a schematic diagram of the internal structure of another boost circuit 110 provided in an embodiment of the present application;

[0054] Fig.10 This is a schematic diagram of an internal structure in which two photovoltaic panel inputs are both positively connected, provided in an embodiment of the present application;

[0055] Fig.11 This is a schematic diagram of the internal structure of a two-way photovoltaic panel with any input reversely connected provided by an embodiment of the present application;

[0056] Fig.12 This is a schematic diagram of an internal structure in which two photovoltaic panel inputs are reversely connected, provided in an embodiment of the present application;

[0057] Fig.13 This is another internal structure schematic diagram of two photovoltaic panel inputs both connected in positive direction provided by an embodiment of the present application;

[0058] Fig.14 This is another internal structure diagram of a two-way photovoltaic panel with any input reversely connected provided by an embodiment of the present application;

[0059] Fig.15 This is another internal structure schematic diagram of another embodiment of the present application in which both photovoltaic panel inputs are reversely connected. DETAILED DESCRIPTION

[0060] The embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0061] For ease of understanding, the following examples provide some explanations of concepts related to the embodiments of the present application for reference. As shown below:

[0062] New energy refers to various energy forms that have just begun to be developed or are being actively studied and promoted, other than traditional energy. Such as solar energy, geothermal energy, wind energy, ocean energy, biomass energy and nuclear fusion energy. Common new energy sources include solar energy, which includes solar photovoltaics. Photovoltaic panel components are a type of power generation device that generates direct current when exposed to sunlight. In the power generation system, the purpose of the inverter is to convert direct current into alternating current that is compatible with the power grid.

[0063] Figure 11 is a schematic diagram of an application scenario and an internal structure of an inverter provided in an embodiment of the present application. The inverter 100 includes a boost circuit 110, a DC bus DC Bus 120, and an inverter circuit 130. The input end of the boost circuit 110 is connected to the input end of the inverter 100, the output end of the boost circuit 110 is connected to the DC bus DC Bus 120, the input end of the inverter circuit 130 is connected to the DC bus DC Bus 120, and the output end of the inverter circuit 130 is connected to the output end of the inverter 100.

[0064] The boost circuit 110 boosts the DC voltage of the photovoltaic module PV to the DC voltage required for the output control of the inverter 100, and the inverter circuit 130 converts the boosted DC voltage into an AC voltage of the frequency required by the power grid. During normal power generation, the input end of the inverter 100 is connected to the photovoltaic module PV, which can be composed of a plurality of photovoltaic panels connected in series and parallel. The output end of the inverter 100 is connected to the power grid, and the inverter 100 converts the DC power input by the photovoltaic module PV into AC power and outputs it to the power grid.

[0065] In actual use, the input end of the inverter 100 usually includes multiple DC input interfaces, and the installer or maintenance personnel may make mistakes when plugging the DC input cable, resulting in reverse connection. In order to achieve the purpose of improving the safety of the equipment, the present application improves the design of the first-stage boost circuit of the inverter 100, so that the inverter 100 has the function of preventing reverse connection, thereby enabling the installer or maintenance personnel to reduce the occurrence of reverse connection when connecting the circuit, and effectively protecting the power device.

[0066] Combine the following Figure 2 , Figure 3 and Figure 4 and Figure 5 , respectively, in the case of positive input connection and reverse input connection in the prior art, the structure of the boost circuit is described in detail, specifically:

[0067] Figure 2An internal structure diagram of a positive input is illustrated, the boost circuit 110 includes a positive input terminal BST+ and a negative input terminal BST- located on the right side of the high-voltage DC switch 140, a boost inductor L1, a power switch tube S1, a parasitic diode D1 and a diode D2 of the power switch tube S1, the input end of the boost circuit 110 is connected to the input end of the inverter 100 through the high-voltage DC switch 140, and the boost circuits in the embodiments described below all adopt similar connection methods, which will not be described in detail. The inverter 100 inputs a voltage from the photovoltaic panel PV, wherein the PV- on the left side of the high-voltage DC switch 140 is the same as the BST- on the right side of the high-voltage DC switch 140, and the PV+ on the left side of the high-voltage DC switch 140 is the same as the BST+ on the right side of the high-voltage DC switch 140, indicating that the PV input is positively connected. At this time, the on-off of the power switch tube S1 can be controlled to realize Boost boost, and the DC power input from the photovoltaic module PV is boosted and output to the DC bus DC Bus120, so that the boost circuit 110 can operate normally.

[0068] Figure 3 An internal structure schematic diagram of two inputs being positively connected is illustrated, and the inverter 100 inputs two voltages (such as PVA and PVB) from the photovoltaic panel, wherein the boost circuit 110 is designed such that the positive input terminals BST1+ and BST2+ of the two DC inputs are independently set for receiving the positive inputs of PVA and PVB respectively, and the BST1- and BST2- of the two DC input terminals are combined into BST12-, and the negative inputs from PVA and PVB are received by BST12-, and the PVA- and PVB- on the left side of the high-voltage DC switch 140 are the same as the BST1- and BST2- on the right side of the high-voltage DC switch 140, indicating that the PVA branch and the PVB branch are both positively connected. At this time, the on-off of the first power switch tube S1 and the second power switch tube S2 can be controlled to realize Boost boosting, and the DC power input from the photovoltaic panel PVA and the photovoltaic panel PVB is boosted and output to the DC bus DC Bus120, so that the boost circuit 110 can operate normally.

[0069] Figure 4An internal structure schematic diagram of a case where any input of two photovoltaic panels is reversely connected is illustrated. When one of the photovoltaic inputs of the inverter 100 is reversely connected, PVA- on the left side of the high-voltage DC switch 140 is opposite to BST1+ on the right side of the high-voltage DC switch 140, and PVB- on the left side of the high-voltage DC switch 140 is the same as BST2- on the right side of the high-voltage DC switch 140, indicating that the PVA branch input is reversely connected and the PVB branch input is forwardly connected. At this time, the input of the photovoltaic panel PVA is approximately short-circuited through the body diode D1 of the first power switch tube S1 and the body diode D2 of the second power switch tube S2. The short-circuit current Isc of the photovoltaic panel flows through the body diode D1, which will cause a large loss (loss Ploss = short-circuit current Isc*forward voltage Vf), which may damage the power switch tube.

[0070] Figure 5 An internal structure schematic diagram of two photovoltaic panel inputs is illustrated. When the photovoltaic inputs are both reversed, PVA- and PVB- on the left side of the high-voltage DC switch 140 are opposite to BST1+ and BST2+ on the right side of the high-voltage DC switch 140, indicating that both the PVA branch and the PVB branch inputs are reversed.

[0071] against Figure 4 For the circuit structure of any photovoltaic input reverse connection shown in the figure, the existing protection method can be: the detection unit samples the branch input voltage and branch input current to determine if the PVA branch input polarity is reversed, and the protection unit sends a driving signal to turn on the power tube (SiC MOSFET), and the short-circuit current Isc flows through the body diode D2. Since the conduction impedance of the first power switch tube S1 is small, the loss generated is not large and will not cause device damage. However, for Figure 5 The circuit structure shown in the figure has reverse input of both photovoltaic branches. Since the normal operation of the detection unit and the protection unit requires the start-up of the internal auxiliary power source of the inverter, when the inputs of both branches are reversed, the internal auxiliary power supply of the system cannot be started normally, and the detection function of the controller cannot work normally, and finally the reverse polarity protection cannot be implemented.

[0072] In order to solve the technical problem that reverse polarity protection cannot be implemented when the inputs of the two branches are reversed, the embodiment of the present application provides a new inverter architecture and proposes a new circuit control method based on the architecture, which can effectively protect the power devices even when the inputs of the two branches are reversed.

[0073] Combine the following Figure 6 , Figure 7 and Figure 8 and Fig. 9 , the structure of the boost circuit 110 is first described in detail, specifically:

[0074] Figure 61 is a schematic diagram of the internal structure of a boost circuit 110 provided in an embodiment of the present application, wherein the boost circuit 110 includes a first power device 111, a first positive circuit 113 and a first negative circuit 114, the input end of the boost circuit 110 includes a first positive input end BST1+ and a first negative input end BST1-, the first power device 111 includes a first power switch tube S1 and a body diode D1 of the first power switch tube S1; the DC bus DC Bus120 includes a bus capacitor C1; the first positive circuit 113 includes a first boost diode D2 (wherein the direction of the first boost diode D2 is opposite to the direction of the positive input end) and a first boost inductor L1, the first positive input end BST1+ is connected to one end of the first boost inductor L1, the other end of the first boost inductor L1 is connected to one end of the first boost diode D2, the other end of the first boost diode D2 is connected to the positive terminal of the bus capacitor C1, the first negative circuit 114 includes a first anti-reverse module 115, the first negative The pole input terminal BST1- is connected to one end of the first anti-reverse module 115, the first anti-reverse module 115 is connected to the negative terminal of the bus capacitor C1, one end of the first power switch tube S1 is connected between the first boost inductor L1 and the first boost diode D2, the other end of the first power switch tube S1 is connected between the other end of the first anti-reverse module 115 and the negative terminal of the bus capacitor C1, the first anti-reverse module 115 includes a first anti-reverse switch K1 and a first anti-reverse diode D3 connected in parallel, and optionally, the first anti-reverse switch K1 is a normally open switch.

[0075] Figure 71 is a schematic diagram of the internal structure of a boost circuit 110 when two inputs are combined provided in an embodiment of the present application. Two photovoltaic panel input branches are combined, and the two inputs have a common anti-reverse module. The boost circuit 110 includes a second power device 112, a second positive circuit 116, and a second negative circuit 117. The second power device 112 includes a second power switch tube S2 and a body diode D5 of the second power switch tube S2. The second positive circuit 116 includes a second boost diode D4 and a second boost inductor L2. The input of the boost circuit 110 The input end includes a second positive input end BST2+, the second positive input end BST2+ is connected to one end of the second boost inductor L2, the other end of the second boost inductor L2 is connected to one end of the second boost diode D4, the other end of the second boost diode D4 is connected to the positive end of the bus capacitor C1, one end of the second power switch tube S2 is connected between the second boost inductor L2 and the second boost diode D4, and the other end of the second power switch tube S2 is connected between the other end of the first anti-reverse module 115 and the negative end of the bus capacitor C1. Among them, the boost circuit 110 is designed as the positive input ends BST1+ and BST2+ of the two DC inputs are independently set, respectively, for receiving the positive inputs of PVA and PVB, and the first negative input end BST1- and the second positive input end BST2- of the two DC input ends are combined into BST12-, and BST12- receives the negative inputs from PVA and PVB.

[0076] It should be noted that, for the case where two inputs are combined, different from the internal structure of the boost circuit in the prior art, the internal structure of the boost circuit in this scheme adds a first anti-reverse module 115 connected in parallel by a first anti-reverse switch K1 and a first anti-reverse diode D3, the first negative input terminal BST1- is connected to one end of the first anti-reverse module 115, and the first anti-reverse module 115 is connected to the negative terminal of the bus capacitor C1. The purpose of protecting the power device is achieved by controlling the first anti-reverse module 115.

[0077] Figure 81 is a schematic diagram of the internal structure of a boost circuit 110 when two inputs are not connected in an embodiment of the present application. The two photovoltaic panel input branches are not connected in an integrated manner, and the two inputs each have their own anti-reverse module. Specifically, the boost circuit 110 includes a third power switch tube S2, a third positive circuit and a third negative circuit; the third positive circuit includes a third boost diode D4 and a third boost inductor L2, and the input end of the boost circuit 110 includes a third positive input end and a third negative input end. The third positive input end BST2+ is connected to one end of the third boost inductor L2, and the other end of the third boost inductor L2 is connected to one end of the third boost diode D4. The third boost diode D4 is connected to the positive terminal of the bus capacitor C1; the third negative circuit includes a second anti-reverse module 118, the third negative input terminal BST2- is connected to one end of the second anti-reverse module 118, the second anti-reverse module 118 is connected to the negative terminal of the bus capacitor C1, one end of the third power switch tube S2 is connected between the third boost inductor L2 and the third boost diode D4, the other end of the third power switch tube S2 is connected between the other end of the second anti-reverse module 118 and the negative terminal of the bus capacitor C1, and the second anti-reverse module 118 includes a second anti-reverse switch K2 and a second anti-reverse diode D6 connected in parallel. Optionally, the second anti-reverse switch K2 is a normally open switch.

[0078] It should be noted that the third positive input terminal can be one of the first positive input terminal BST1+ or the second positive input terminal BST2+. The third positive input terminal is taken as the second positive input terminal BST2+, the third negative input terminal is taken as the second negative input terminal BST2-, and the third power switch tube is taken as the second power switch tube S2 for example. The corresponding components are also taken as the components of the second positive circuit 116 and the second negative circuit 117 for example, and will not be repeated in detail later.

[0079] It should be noted that, for the case where the two inputs are not combined, different from the internal structure of the boost circuit in the prior art, the internal structure of the boost circuit in this scheme adds a first anti-reverse module 115 connected in parallel by a first anti-reverse switch K1 and a first anti-reverse diode D3, and adds a second anti-reverse module 118 connected in parallel by a second anti-reverse switch K2 and a second anti-reverse diode D6. The third negative input terminal BST2- is connected to one end of the second anti-reverse module 118, and the second anti-reverse module 118 is connected to the negative terminal of the bus capacitor C1. The first anti-reverse module 115 and the second anti-reverse module 118 are controlled separately, thereby achieving the purpose of protecting the power device.

[0080] Furthermore, Fig. 9 is a schematic diagram of the internal structure of another boost circuit 110 provided in an embodiment of the present application. Figure 1-Figure 8On the basis of the inverter 100, the inverter 100 also includes an auxiliary power supply 150 and a controller 160. It should be noted that in different schemes of the embodiments of the present application, the auxiliary power supply 150 can be a first auxiliary power supply, a second auxiliary power supply, or a third auxiliary power supply, and correspondingly, the controller 160 can be a first controller, a second controller, or a third controller, which will not be elaborated later.

[0081] Among them, since there is only one photovoltaic panel input in the circuit, when one photovoltaic panel input is connected to the inverter 100, there will be two situations: positive connection and reverse connection. When the input is positively connected, the positive input terminal corresponding to the photovoltaic panel is connected to the first positive input terminal BST1+, and the negative input terminal corresponding to the photovoltaic panel is connected to the first negative input terminal BST1-; when the input is reversely connected, the positive input terminal corresponding to the photovoltaic panel is connected to the first negative input terminal BST1-, and the negative input terminal corresponding to the photovoltaic panel is connected to the first positive input terminal BST1+. In the embodiment of the present application, the normal operation of the controller 160 requires the auxiliary power supply 150 to be started normally before it can supply power to it normally, as follows:

[0082] In the case of reverse connection of the photovoltaic panel input, there is no external forward current flowing into the boost circuit 110. At this time, the auxiliary power supply 150 cannot start normally, and the controller 160 will not work. Since the short-circuit loop of the first anti-reverse switch K1 is disconnected when it is in the normally open state, it will not cause abnormal heating of the first power switch tube S1, thereby achieving the purpose of protecting the first power switch tube S1. Only when the photovoltaic panel input is positively connected, the photovoltaic panel can charge the bus capacitor C1 through the loop composed of the first boost diode D2 and the first anti-reverse diode D3, and the bus capacitor C1 supplies power to the parallel auxiliary power supply 150, so that the auxiliary power supply 150 can start normally. When the auxiliary power supply 150 starts normally, the controller 160 works normally, and then when the controller 160 detects that the voltage difference between the first positive input terminal BST+ and the first negative input terminal BST1- is positive, the first anti-reverse switch K1 is controlled to be closed.

[0083] In an optional implementation, as shown in Table 1, the voltage difference between the first positive input terminal BST1+ and the first negative input terminal BST1- is detected by the controller 160 (i.e., the first controller). If the voltage difference is a positive value, it indicates that the photovoltaic panel input is positively connected and the circuit can operate normally. At this time, the first anti-reverse switch K1 can be controlled to close by the controller 160; if the voltage difference is a negative value, it indicates that the photovoltaic panel input is reversely connected. Since the first anti-reverse switch K1 is a normally open switch, the controller 160 does not perform a control action, and the first anti-reverse switch K1 is still in a disconnected state. Through such a design, when the photovoltaic input polarity is reversed, the short-circuit loop of the photovoltaic panel through the body diode D1 of the first power switch tube S1 is disconnected by the first anti-reverse switch K1 and the single-phase conductive first anti-reverse diode D3, so that a short-circuit loop will not be generated, and the power devices in the inverter 100 will not be damaged, thereby achieving the purpose of protecting the power devices.

[0084] Alternatively, the controller 160 may detect the current value of the first positive input terminal BST1+ or the current value of the first negative input terminal BST1-. If the current value is positive, such as Fig. 9 As shown, when determining whether reverse connection occurs by detecting current, signal a can be the current signal of the first positive input terminal BST1+ in the boost circuit 110 detected by the controller 160, and signal b can be the current signal of the first negative input terminal BST1- in the boost circuit 110 detected by the controller 160. As long as one of the current signals is positive (in fact, in the boost circuit 110, the first positive input terminal BST1+ and the first negative input terminal BST1- exist in the same loop, so the result of the current values ​​detected by them at the same time is The same, that is, the current values ​​obtained by signal a and signal b are the same), it indicates that the photovoltaic panel input is connected positively, and the first anti-reverse switch K1 is controlled to be closed by the controller 160; if the current value is 0, it indicates that the photovoltaic panel input is connected reversely (in the existing scheme, if the current value at the input end is a negative value, it indicates that the input is reversed, and the reverse current in this scheme is blocked by the first anti-reverse diode D3 and cannot flow through, so when the reverse current is 0, it indicates that the photovoltaic panel input is reversed), the first anti-reverse switch K1 is in the open state, and this application does not limit the parameters of the above detection.

[0085]

[0086] Table 1

[0087] Combine the following Figure 10-15 , in the case where the auxiliary power supply 150 and the controller 160 are added, the process of protecting the power device from damage is described in detail for the cases where the two branch inputs are combined and not combined (the above two cases both include three possible modes: at least one branch is reversely connected, all inputs are positively connected, and all inputs are reversely connected), specifically:

[0088] Case 1: Fig.10 It is a schematic diagram of the internal structure of two photovoltaic panel inputs that are both positively connected provided by an embodiment of the present application. When the two photovoltaic panel input branches are combined, PVA+ on the right side of the photovoltaic panel PVA is the same as the first positive input terminal BST1+, and PVB+ on the right side of the photovoltaic panel PVB is also the same as the second positive input terminal BST2+, indicating that both the PVA branch and the PVB branch are positively connected. The controller 160 is used to control the first anti-reverse switch K1 to close when it is detected that the voltage difference between the first positive input terminal BST1+ and the first negative input terminal BST1- is a positive value and the voltage difference between the second positive input terminal BST2+ and the first negative input terminal BST1- is a positive value. Since a short circuit will not be generated when the current flows in the forward direction, the first anti-reverse switch K1 is controlled to close by the controller 160, and the first power switch tube S1 and the second power switch tube S2 will not be damaged.

[0089] Fig.11 This is a schematic diagram of the internal structure of a two-way photovoltaic panel with any input reversed, provided in an embodiment of the present application. The PVA- on the right side of the photovoltaic panel PVA is opposite to the first positive input terminal BST1+, and the PVB+ on the right side of the photovoltaic panel PVB is the same as the second positive input terminal BST2+, indicating that the PVA branch input is reversed, and the PVB branch input is positively connected, or, Fig.12 It is a schematic diagram of the internal structure of a two-way photovoltaic panel input reversely connected provided by an embodiment of the present application. The two-way photovoltaic panel input is reversely connected. If the first anti-reverse switch K1 is closed when at least one input is reversely connected, a short circuit will appear in the entire circuit, thereby damaging the power device. Therefore, in this solution, in order to achieve the purpose of protecting the first power switch tube S1 and the second power switch tube S2 from damage, when at least one input is reversely connected, the short circuit of the photovoltaic panel through the body diode D1 of the first power switch tube S1 is disconnected by the first anti-reverse switch K1 and the first anti-reverse diode D3 that is turned on in a single phase, so that a short circuit will not be generated, and the first power switch tube S1 and the second power switch tube S2 in the inverter 100 will not be damaged. The existing solution is different from this solution. When any input is reversely connected, a driving signal is sent through the protection unit to turn on the power tube (SiC MOSFET), and the short-circuit current Isc flows through the body diode D2. Since the conduction impedance of the first power switch tube S1 is small, the loss generated is not large, and the device will not be damaged. However, since the normal operation of the detection unit and the protection unit requires the start-up of the internal auxiliary power source of the inverter, when the inputs of both branches are reversed, the internal auxiliary power supply of the system cannot start normally, which in turn makes the detection function of the controller unable to work normally and ultimately makes it impossible to implement reverse polarity protection.

[0090] In an optional implementation, as shown in Table 2, when there are two photovoltaic panel inputs and the negative input terminals of the input branches are combined, the voltage difference between the first positive input terminal BST1+ and the first negative input terminal BST1-, and the voltage difference between the second positive input terminal BST2+ and the first negative input terminal BST1- can be detected by the controller 160 (i.e., the second controller). If the voltage difference between the two is positive, it indicates that both photovoltaic panel inputs are positively connected, and the first anti-reverse switch K1 is controlled by the controller 160 to be closed; if the voltage difference between the two is negative, it indicates that both photovoltaic panel inputs are reversely connected, and the first anti-reverse switch K1 is in an open state; if any of the voltage difference between the two is a negative value, it indicates that one of the two photovoltaic panel inputs is reversely connected, and the first anti-reverse switch K1 is still in an open state. Alternatively, the controller 160 can also detect the current value of the first positive input terminal BST1+ and the current value of the second positive input terminal BST2+. If both current values ​​are positive, it indicates that both photovoltaic panel inputs are positively connected, and the first anti-reverse switch K1 is controlled to be closed by the controller 160; if both current values ​​are negative, it indicates that both photovoltaic panel inputs are reversely connected, and the first anti-reverse switch K1 is in an open state; if either of the two current values ​​is 0, it indicates that one of the two photovoltaic panel inputs is reversely connected, and the first anti-reverse switch K1 is still in an open state. This application does not limit the parameters of the above detection.

[0091]

[0092] Table 2

[0093] In the second case, when the two photovoltaic panel input branches are not combined, the two inputs each have their own anti-reverse module, and the controller 160 can independently control the anti-reverse switches K1 and K2 on the modules of different schemes. Fig.13 It is another internal structure schematic diagram of two photovoltaic panel inputs that are both positively connected provided by an embodiment of the present application. PVA+ on the right side of the photovoltaic panel PVA is the same as the first positive input terminal BST1+, indicating that the PVA branch input is positively connected. PVB+ on the right side of the photovoltaic panel PVB is the same as the second positive input terminal BST2+, indicating that the PVB branch input is positively connected. Since a short circuit will not be generated when the current flows in the forward direction, the controller 160 controls the first anti-reverse switch K1 to be closed when the voltage difference between the first positive input terminal BST1+ and the first negative input terminal BST1- is detected to be a positive value. When the voltage difference between the second positive input terminal BST2+ and the second negative input terminal BST2- is detected to be a positive value, the second anti-reverse switch K2 is controlled to be closed, and the first power switch tube S1 and the second power switch tube S2 will not be damaged.

[0094] Fig.14It is a schematic diagram of the internal structure of another type of two photovoltaic panels with either input reversely connected provided in an embodiment of the present application. PVA+ on the right side of the photovoltaic panel PVA is the same as the first positive input terminal BST1+, and PVB- on the right side of the photovoltaic panel PVB is opposite to the second positive input terminal BST2+, indicating that the PVA branch input is positively connected and the PVB branch input is reversely connected. Therefore, the controller 160 can control the first anti-reverse switch K1 to be closed when it is detected that the voltage difference between the first positive input terminal BST1+ and the first negative input terminal BST1- is a positive value, and the second anti-reverse switch K2 is in an open state when it is detected that the voltage difference between the second positive input terminal BST1+ and the second negative input terminal BST1- is a negative value.

[0095] Fig.15 It is a schematic diagram of the internal structure of another embodiment of the present application in which both photovoltaic panel inputs are reversely connected. In this scheme, in order to achieve the purpose of protecting the first power switch tube S1 and the second power switch tube S2 from damage, when both inputs are reversely connected, the short-circuit loop of the photovoltaic panel through the body diode D1 of the first power switch tube S1 is disconnected by the first anti-reverse switch K1 and the single-phase first anti-reverse diode D3, and the short-circuit loop of the photovoltaic panel through the body diode D5 of the second power switch tube S2 is disconnected by the second anti-reverse switch K2 and the single-phase second anti-reverse diode D6, so that a short-circuit loop will not be generated, and the first power switch tube S1 and the second power switch tube S2 in the inverter 100 will not be damaged.

[0096] In an optional implementation, as shown in Table 3, when there are two photovoltaic panel inputs and the input branches are not connected, the controller 160 (i.e., the third controller) can detect the voltage difference between the first positive input terminal BST1+ and the first negative input terminal BST1-, and the voltage difference between the second positive input terminal BST2+ and the second negative input terminal BST1-. If the voltage difference between the two is a positive value, it indicates that the two photovoltaic panel inputs are positively connected, and the controller 160 controls the first anti-reverse switch K1 to be closed, and controls the second anti-reverse switch K2 to be closed; if the voltage difference between the two is a negative value, it indicates that the two photovoltaic panel inputs are reversely connected, the first anti-reverse switch K1 is in an open state, and the second anti-reverse switch K2 is in an open state; if one of the voltage differences is a positive value and the other is a negative value, it indicates that one of the two photovoltaic panel inputs is positively connected and the other is reversely connected, the first anti-reverse switch K1 is in an open state, and the second anti-reverse switch K2 is controlled to be closed; or the second anti-reverse switch K2 is in an open state, and the first anti-reverse switch K1 is controlled to be closed. Alternatively, the controller 160 may also detect the current value of the first positive input terminal BST1+ and the current value of the second positive input terminal BST2+. If both current values ​​are positive, it indicates that both photovoltaic panel inputs are positively connected, and the controller 160 controls the first anti-reverse switch K1 to be closed, and controls the second anti-reverse switch K2 to be closed; if both current values ​​are 0, it indicates that both photovoltaic panel inputs are reversely connected, the first anti-reverse switch K1 is in an open state, and the second anti-reverse switch K2 is in an open state; if one of the two current values ​​is positive and the other is 0, it indicates that one of the two photovoltaic panel inputs is positively connected and the other is reversely connected, the first anti-reverse switch K1 is in an open state, and the second anti-reverse switch K2 is controlled to be closed; or the second anti-reverse switch K2 is in an open state, and the first anti-reverse switch K1 is controlled to be closed. The present application does not limit the parameters of the above detection.

[0097]

[0098] Table 3

[0099] The controller 160 in the inverter 100 can be at least one processor, wherein the processor is a module that performs arithmetic operations and / or logical operations, and can specifically be a central processing unit (CPU), a microprocessor (MPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a complex programmable logic device (CPLD), a coprocessor (assisting the central processing unit to complete corresponding processing and application), a microcontroller unit (MCU) and other processing modules or a combination of multiple thereof. The controller 160 integrates detection and control functions, which can be integrated in one module or in separate modules.

[0100] In an optional implementation, the controller 160 is further configured to output an alarm signal when the photovoltaic panel input is reversely connected.

[0101] Specifically, the inverter 100 can trigger an emergency command through the controller 160 and output an alarm signal, wherein the alarm signal includes causing the inverter 100 to make a sound, a flashing indicator light, etc., wherein the notification message is used to prompt that the inverter 100 is suspected of a fault and request business personnel to troubleshoot the inverter 100.

[0102] In the embodiment of the present application, the added anti-reverse module not only has a simple structure, but also can effectively protect the power switch tube regardless of whether the input is connected in a positive and reverse connection or both are reversed, thereby effectively solving the reliability problem of the power semiconductor when the photovoltaic input polarity is reversed.

[0103] The present application also provides a power conversion circuit, the power conversion circuit comprising a first power switch tube, a first positive circuit, a first negative circuit and a DC bus; the first positive circuit comprises a first boost diode and a first boost inductor, the first negative circuit comprises a first anti-reverse module, and the input end of the power conversion circuit comprises a first positive input end and a first negative input end;

[0104] The DC bus includes a bus capacitor;

[0105] The first positive input terminal is connected to one end of the first boost inductor, the other end of the first boost inductor is connected to one end of the first boost diode, the other end of the first boost diode is connected to the positive end of the bus capacitor, the first negative input terminal is connected to one end of the first anti-reverse module, the other end of the first anti-reverse module is connected to the negative end of the bus capacitor, one end of the first power switch tube is connected between the first boost inductor and the first boost diode, the other end of the first power switch tube is connected between the other end of the first anti-reverse module and the negative end of the bus capacitor, and the first anti-reverse module includes a first anti-reverse switch and a first anti-reverse diode connected in parallel.

[0106] The present application also provides a photovoltaic system, comprising Figure 1 The inverter and photovoltaic module, the input end of the inverter is connected to the photovoltaic module, the output end of the inverter is used to connect to the power grid, the inverter is used to convert the direct current output by the photovoltaic module into alternating current and output it to the load, the load can be a power grid, household electrical equipment, industrial electrical equipment, etc.

[0107] It should be noted that, unless otherwise specified, the ordinal numbers such as "first" and "second" used in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, timing, priority or importance of multiple objects. For example, the first device and the second device are only for the convenience of description, and do not represent the difference in structure, importance, etc. between the first device and the second device. In some embodiments, the first device and the second device can also be the same device.

[0108] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An inverter, characterized in that: The inverter includes a boost circuit, a DC bus and an inverter circuit; The input end of the boost circuit is connected to the input end of the inverter, the output end of the boost circuit is connected to the DC bus, the input end of the inverter circuit is connected to the DC bus, and the output end of the inverter circuit is connected to the output end of the inverter; The boost circuit includes a first power switch tube, a first positive circuit and a first negative circuit, the first positive circuit includes a first boost diode and a first boost inductor, the first negative circuit includes a first anti-reverse module, the input end of the boost circuit includes a first positive input end and a first negative input end, and the DC bus includes a bus capacitor; The first positive input terminal is connected to one end of the first boost inductor, the other end of the first boost inductor is connected to one end of the first boost diode, the other end of the first boost diode is connected to the positive end of the bus capacitor, the first negative input terminal is connected to one end of the first anti-reverse module, the other end of the first anti-reverse module is connected to the negative end of the bus capacitor, one end of the first power switch tube is connected between the first boost inductor and the first boost diode, the other end of the first power switch tube is connected between the other end of the first anti-reverse module and the negative end of the bus capacitor, and the first anti-reverse module includes a first anti-reverse switch and a first anti-reverse diode connected in parallel.

2. The inverter according to claim 1, characterized in that: The boost circuit includes a second power switch tube and a second positive circuit, and the input end of the boost circuit includes a second positive input end; the second positive circuit includes a second boost diode and a second boost inductor, the second positive input end is connected to one end of the second boost inductor, the other end of the second boost inductor is connected to one end of the second boost diode, the other end of the second boost diode is connected to the positive end of the bus capacitor, one end of the second power switch tube is connected between the second boost inductor and the second boost diode, and the other end of the second power switch tube is connected between the other end of the first anti-reverse module and the negative end of the bus capacitor.

3. The inverter according to claim 1, characterized in that: The boost circuit includes a third power switch tube, a third positive circuit and a third negative circuit, and the input end of the boost circuit includes a third positive input end and a third negative input end; the third positive circuit includes a third boost diode and a third boost inductor, the third positive input end is connected to one end of the third boost inductor, the other end of the third boost inductor is connected to one end of the third boost diode, and the other end of the boost diode is connected to the positive end of the bus capacitor; the third negative circuit includes a second anti-reverse module, the third negative input end is connected to one end of the second anti-reverse module, the second anti-reverse module is connected to the negative end of the bus capacitor, one end of the third power switch tube is connected between the third boost inductor and the third boost diode, the other end of the third power switch tube is connected between the other end of the second anti-reverse module and the negative end of the bus capacitor, and the second anti-reverse module includes a second anti-reverse switch and a second anti-reverse diode connected in parallel.

4. The inverter according to claim 1, characterized in that: The inverter includes a first auxiliary power supply and a first controller, wherein the bus capacitor is used to charge the first auxiliary power supply, and the first auxiliary power supply is used to power the first controller; the first controller is used to control the first anti-reverse switch to close when the voltage difference between the first positive input terminal and the first negative input terminal is positive, or, The first controller is used to control the first anti-reverse switch to close when the current value of the first positive input terminal or the first negative input terminal is positive.

5. The inverter according to claim 2, characterized in that: The inverter includes a second auxiliary power supply and a second controller, the bus capacitor is used to charge the second auxiliary power supply, and the second auxiliary power supply is used to supply power to the second controller; The second controller is used to control the first anti-reverse switch to close when the voltage difference between the first positive input terminal and the first negative input terminal is positive and the voltage difference between the second positive input terminal and the first negative input terminal is positive, or, The second controller is used to control the first anti-reverse switch to close when the current value of the first positive input terminal and the current value of the second positive input terminal are both positive.

6. The inverter according to claim 3, characterized in that: The inverter comprises a third auxiliary power supply and a third controller, the bus capacitor is used to charge the third auxiliary power supply, and the third auxiliary power supply is used to supply power to the third controller; The third controller is used to control the second anti-reverse switch to close when the voltage difference between the third positive input terminal and the third negative input terminal is positive, or, The third controller is used to control the second anti-reverse switch to close when the current value of the third positive input terminal or the third negative input terminal is positive.

7. The inverter according to any one of claims 1 to 6, characterized in that: The first anti-reverse switch is a normally open switch.

8. The inverter according to claim 3 or 6, characterized in that: The second anti-reverse switch is the normally open switch.

9. A power conversion circuit, characterized in that: The power conversion circuit includes a first power switch tube, a first positive circuit, a first negative circuit and a DC bus; The first positive circuit includes a first boost diode and a first boost inductor, the first negative circuit includes a first anti-reverse module, the input end of the power conversion circuit includes a first positive input end and a first negative input end, and the DC bus includes a bus capacitor; The first positive input terminal is connected to one end of the first boost inductor, the other end of the first boost inductor is connected to one end of the first boost diode, the other end of the first boost diode is connected to the positive end of the bus capacitor, the first negative input terminal is connected to one end of the first anti-reverse module, the other end of the first anti-reverse module is connected to the negative end of the bus capacitor, one end of the first power switch tube is connected between the first boost inductor and the first boost diode, the other end of the first power switch tube is connected between the other end of the first anti-reverse module and the negative end of the bus capacitor, and the first anti-reverse module includes a first anti-reverse switch and a first anti-reverse diode connected in parallel.

10. The power conversion circuit according to claim 9, characterized in that: The power conversion circuit includes a second power switch tube and a second positive circuit, and the input end of the power conversion circuit includes a second positive input end; the second positive circuit includes a second boost diode and a second boost inductor, the second positive input end is connected to one end of the second boost inductor, the other end of the second boost inductor is connected to one end of the second boost diode, the other end of the second boost diode is connected to the positive end of the bus capacitor, one end of the second power switch tube is connected between the second boost inductor and the second boost diode, and the other end of the second power switch tube is connected between the other end of the first anti-reverse module and the negative end of the bus capacitor.

11. The power conversion circuit according to claim 9, characterized in that: The power conversion circuit includes a third power switch tube, a third positive circuit and a third negative circuit, and the input end of the power conversion circuit includes a third positive input end and a third negative input end; the third positive circuit includes a third boost diode and a third boost inductor, the third positive input end is connected to one end of the third boost inductor, the other end of the third boost inductor is connected to one end of the third boost diode, and the other end of the boost diode is connected to the positive end of the bus capacitor; the third negative circuit includes a second anti-reverse module, the third negative input end is connected to one end of the second anti-reverse module, the second anti-reverse module is connected to the negative end of the bus capacitor, one end of the third power switch tube is connected between the third boost inductor and the third boost diode, the other end of the third power switch tube is connected between the other end of the second anti-reverse module and the negative end of the bus capacitor, and the second anti-reverse module includes a second anti-reverse switch and a second anti-reverse diode connected in parallel.

12. The power conversion circuit according to claim 9, characterized in that: The first anti-reverse switch is used to close when the voltage difference between the first positive input terminal and the first negative input terminal is positive, or, The first anti-reverse switch is further configured to be closed when the current value at the first positive input terminal or the first negative input terminal is positive.

13. The power conversion circuit according to claim 10, characterized in that: The first anti-reverse switch is used to close when the voltage difference between the first positive input terminal and the first negative input terminal is positive and the voltage difference between the second positive input terminal and the first negative input terminal is positive, or, The first anti-reverse switch is further configured to close when the current value at the first positive input terminal and the current value at the second positive input terminal are both positive.

14. The power conversion circuit according to claim 11, characterized in that: The second anti-reverse switch is used to close when the voltage difference between the third positive input terminal and the third negative input terminal is positive, or, The second anti-reverse switch is further configured to close when the current value at the third positive input terminal or the third negative input terminal is positive.

15. The power conversion circuit according to any one of claims 9 to 14, characterized in that: The first anti-reverse switch is a normally open switch.

16. The power conversion circuit according to claim 11 or 14, characterized in that: The second anti-reverse switch is the normally open switch.

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