Photovoltaic grid-connected circuit and photovoltaic grid-connected inverter
By adding inductors and lightning protection units to photovoltaic grid-connected inverters, the problems of leakage current and lightning energy damage to devices are solved, and the safety protection of photovoltaic grid-connected inverters is realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2026-03-31
AI Technical Summary
In existing grid-connected photovoltaic inverters, when the classic BOOST topology is used, the negative terminal of the photovoltaic panel is directly connected to the grid, causing leakage current to form a loop and damaging the device.
Adding an extra inductor, especially a second inductor, to a photovoltaic grid-connected inverter suppresses the rate of change of leakage current and releases lightning strike energy through a lightning protection unit, thus protecting the device.
It effectively suppresses the impact of leakage current on devices, prevents device damage, and improves the reliability and safety of photovoltaic grid-connected inverters.
Smart Images
Figure CN224068367U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of photovoltaic technology, and in particular to a photovoltaic grid-connected circuit and a photovoltaic grid-connected inverter. Background Technology
[0002] Photovoltaic power generation is now very common, and photovoltaic panels are ubiquitous. Photovoltaic panels convert solar energy into electrical energy, which is then connected to the power grid through a photovoltaic grid-connected inverter to realize the utilization of the converted electrical energy.
[0003] Grid-connected photovoltaic inverters realize the transformation, inversion, and filtering of electrical energy converted from photovoltaic panels. In existing technologies, grid-connected photovoltaic inverters mostly use the classic BOOST topology to transform the electrical energy converted from photovoltaic panels.
[0004] However, when the electrical energy converted from the photovoltaic panel is transformed using the classic BOOST topology, the negative terminal of the photovoltaic panel is directly connected to the negative terminal of the grid. In some cases, a loop is formed between the negative terminal of the photovoltaic panel and the ground. The resulting leakage current passes through the devices in the photovoltaic grid-connected inverter, causing impact to some devices and potentially damaging them. Utility Model Content
[0005] This application provides a photovoltaic grid-connected circuit and a photovoltaic grid-connected inverter, which can solve the technical problem that leakage current in photovoltaic grid-connected inverters using the classic BOOST topology can easily damage the devices.
[0006] In a first aspect, this application provides a photovoltaic grid-connected circuit, which includes a transformer module and an inverter module. The input terminal of the transformer module is connected to the output terminal of the photovoltaic panel, the output terminal of the transformer module is connected to the input terminal of the inverter module, and the output terminal of the inverter module is connected to the power grid, wherein:
[0007] The transformer module includes a first inductor, a second inductor, a switching transistor, a diode, and a capacitor. One end of the first inductor is connected to the positive output terminal of the photovoltaic panel. The other end of the first inductor is connected to the anode of the diode and the first terminal of the switching transistor. The cathode of the diode is connected to one end of the capacitor and the input terminal of the inverter module. The other end of the capacitor is connected to one end of the second inductor, the second terminal of the switching transistor, and the input terminal of the inverter module. The other end of the second inductor is connected to the negative output terminal of the photovoltaic panel.
[0008] In one feasible embodiment of this application, the switching transistor is any one of a power MOSFET, a gallium nitride MOSFET, a silicon carbide MOSFET, or an insulated gate bipolar transistor.
[0009] In an embodiment of the application, the photovoltaic grid-connected circuit further comprises a filter module, one end of the filter module is connected to the output end of the inverter module, the other end of the filter module is connected to the power grid, and the filter module is used to suppress electromagnetic interference of the output of the inverter module.
[0010] In an embodiment of the application, the filter module comprises an EMI filter circuit, the EMI filter circuit comprises an X capacitor, a Y capacitor, a common-mode inductor and a differential-mode inductor, the common-mode inductor and the differential-mode inductor are connected in series between the live wire and the neutral wire of the power grid, the X capacitor is connected across the live wire and the neutral wire of the power grid, the Y capacitor is connected in parallel with the X capacitor, the Y capacitor is connected across the live wire and the ground wire and the neutral wire and the ground wire of the power grid respectively, and the EMI filter circuit is used to suppress common-mode interference and differential-mode interference.
[0011] In an embodiment of the application, the transformer module further comprises a lightning protection unit, a first end of the lightning protection unit is connected between the first inductor and the positive output end of the photovoltaic panel, a second end of the lightning protection unit is connected between the second inductor and the negative output end of the photovoltaic panel, and a third end of the lightning protection unit is connected to the ground wire, and the lightning protection unit is used to release lightning energy to the ground wire when the lightning energy acts on the output end of the photovoltaic panel.
[0012] In an embodiment of the application, the lightning protection unit comprises a first varistor, a second varistor and a third varistor, one end of the first varistor is connected as the first end of the lightning protection unit between the first inductor and the positive output end of the photovoltaic panel, the other end of the first varistor is connected to one end of the second varistor and one end of the third varistor respectively, the other end of the second varistor is connected as the second end of the lightning protection unit between the second inductor and the negative output end of the photovoltaic panel, and the other end of the third varistor is connected as the third end of the lightning protection unit to the ground wire.
[0013] In an embodiment of the application, the lightning protection unit comprises a fourth varistor, a fifth varistor and a gas discharge tube, one end of the fourth varistor is connected as the first end of the lightning protection unit between the first inductor and the positive output end of the photovoltaic panel, the other end of the fourth varistor is connected to one end of the fifth varistor and one end of the gas discharge tube respectively, the other end of the fifth varistor is connected as the second end of the lightning protection unit between the second inductor and the negative output end of the photovoltaic panel, and the other end of the gas discharge tube is connected as the third end of the lightning protection unit to the ground wire.
[0014] In an embodiment of the present application, the circuit topology of the inverter module comprises a non-isolated inverter topology circuit.
[0015] In an embodiment of the present application, the circuit topology of the non-isolated inverter topology circuit comprises a Heric topology.
[0016] In a second aspect, the present application provides a photovoltaic grid-connected inverter, which comprises the photovoltaic grid-connected circuit according to any one of the embodiments of the first aspect.
[0017] The above technical solution provided by the embodiments of the present application has the following advantages compared with the prior art: The technical solution provided by the embodiments of the present application is different from the photovoltaic grid-connected inverter using the classical BOOST topology, and an additional inductor (i.e., a second inductor) is additionally added between the negative terminal of the photovoltaic panel and the power grid, so that the negative terminal of the photovoltaic panel is not directly connected to the power grid. When a loop is formed between the negative terminal of the photovoltaic panel and the ground, the additional inductor increases the impedance of the loop, inhibits the change rate of the leakage current, avoids the impact of the leakage current on the devices in the photovoltaic grid-connected inverter, and further avoids the damage of the devices in the photovoltaic grid-connected inverter due to the leakage current. BRIEF DESCRIPTION OF DRAWINGS
[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and serve to explain the principles of the present application together with the specification.
[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, those skilled in the art can obtain other drawings from these drawings without any creative effort.
[0020] One or more embodiments are illustrated by way of example in the drawings that are for illustrative purposes only, and thus are not to be construed as limiting the embodiments, and elements having the same reference numbers designate corresponding or like elements throughout the drawings, and the drawings are not to scale.
[0021] Figure 1 A first structural schematic diagram of a photovoltaic grid-connected circuit according to an embodiment of the present application;
[0022] Figure 2 A second structural schematic diagram of a photovoltaic grid-connected circuit according to an embodiment of the present application;
[0023] Figure 3 A third structural schematic diagram of a photovoltaic grid-connected circuit according to an embodiment of the present application;
[0024] Figure 4 A fourth structural schematic diagram of a photovoltaic grid-connected circuit provided by an embodiment of the present application;
[0025] Figure 5 A specific connection schematic diagram of a lightning protection unit in a photovoltaic grid-connected circuit provided by an embodiment of the present application;
[0026] Figure 6 Another specific connection schematic diagram of a lightning protection unit in a photovoltaic grid-connected circuit provided by an embodiment of the present application;
[0027] Figure 7 A structural schematic diagram of a photovoltaic grid-connected inverter provided by an embodiment of the present application.
[0028] Reference signs:
[0029] 1, transformer module; 2, inverter module; 3, filter module; 4, lightning protection unit; L1, first inductor; L2, second inductor; L3, third inductor; L4, fourth inductor; Q, switch tube; D, diode; C, capacitor; PV-, negative output end of photovoltaic panel; PV+, positive output end of photovoltaic panel; PE, ground wire; RV1, first voltage-dependent resistor; RV2, second voltage-dependent resistor; RV3, third voltage-dependent resistor; RV4, fourth voltage-dependent resistor; RV5, fifth voltage-dependent resistor; GAS, gas discharge tube; S1, first IGBT tube;
[0030] S2, second IGBT tube; S3, third IGBT tube; S4, fourth IGBT tube; S5, fifth IGBT tube; S6, sixth IGBT tube. DETAILED DESCRIPTION
[0031] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.
[0032] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplicity and clarity, the description of the specific examples in the following text will be described. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to the numbers and / or letters in different examples. Such repetition is for the purpose of simplification and clarity, and it does not indicate the relationship between the various embodiments and / or settings discussed.
[0033] In order to solve the technical problem that the leakage current of the photovoltaic grid-connected inverter adopting the classical BOOST topology in the prior art is easy to cause damage to the device, the application provides a photovoltaic grid-connected circuit and a photovoltaic grid-connected inverter, which can protect the device in the photovoltaic grid-connected inverter from damage caused by the leakage current.
[0034] Figure 1 A first structural schematic diagram of a photovoltaic grid-connected circuit provided by the application is shown in Figure 1. Figure 1 The photovoltaic grid-connected circuit provided by the application includes a voltage conversion module 1 and an inverter module 2, the input end of the voltage conversion module 1 is connected to the output end of a photovoltaic panel, the output end of the voltage conversion module 1 is connected to the input end of the inverter module 2, and the output end of the inverter module 2 is connected to a power grid.
[0035] The voltage conversion module 1 includes a first inductor L1, a second inductor L2, a switch tube Q, a diode D and a capacitor C, one end of the first inductor L1 is connected to the positive output end PV+ of the photovoltaic panel, the other end of the first inductor L1 is respectively connected to the anode of the diode D and the first end of the switch tube Q, the cathode of the diode D is respectively connected to one end of the capacitor C and the input end of the inverter module 2, the other end of the capacitor C is respectively connected to one end of the second inductor L2, the second end of the switch tube Q and the input end of the inverter module 2, and the other end of the second inductor L2 is connected to the negative output end PV- of the photovoltaic panel.
[0036] Specifically, the photovoltaic panel converts solar energy into electric energy, and outputs the converted electric energy to the voltage conversion module 1 for DC-DC voltage conversion, the voltage conversion module 1 outputs the voltage-converted electric energy to the inverter module 2, the inverter module 2 performs DC-AC conversion on the voltage-converted electric energy, and finally outputs the electric energy to the power grid.
[0037] The voltage conversion principle of the voltage conversion module 1 in the technical solution provided by the application is the same as that of the classical BOOST topology, during charging, the switch tube Q is turned on, the electric energy input by the photovoltaic panel flows through the first inductor L1, the capacitor C stores the electric energy, and the voltage across the capacitor C rises; during discharging, the switch tube Q is turned off, the first inductor L1 slowly discharges to the capacitor C, the voltage across the capacitor C continuously rises, and finally is higher than the voltage input by the photovoltaic panel, thereby realizing voltage conversion.
[0038] The switch tube Q in the voltage conversion module 1 is used to control the charging and discharging of the first inductor L1 and the capacitor C, and the switch tube Q only needs to be capable of being controlled to be switched on and off. In a feasible embodiment of the application, the switch tube Q is any one of a power field effect transistor, a gallium nitride field effect transistor, a silicon carbide field effect transistor or an insulated gate bipolar transistor.
[0039] In some practical scenarios, the negative output end PV- of the photovoltaic panel is short-circuited to the ground PE, at this time, a loop is formed between the negative output end PV- of the photovoltaic panel, the voltage transformation module 1, the inverter module 2, the ground PE and the negative output end PV- of the photovoltaic panel, and a leakage current is generated. In the technical solution provided in the present application, a second inductor L2 is added in the voltage transformation module 1, when the leakage current is generated, the leakage current will necessarily pass through the second inductor L2, and due to the current retention characteristic of the inductor, the change rate of the generated leakage current is inhibited by the second inductor L2, so that the leakage current cannot quickly act on the inverter module 2, and further cannot generate an impact on the power tube device contained in the inverter module 2.
[0040] The technical solution provided in the embodiment of the present application is different from the photovoltaic grid-connected inverter adopting the classical BOOST topology, and an additional inductor (i.e. the second inductor L2) is additionally added between the negative end of the photovoltaic panel and the power grid, so that the negative output end PV- of the photovoltaic panel is not directly connected to the power grid. When a loop is formed between the negative output end PV- of the photovoltaic panel and the ground, the additional inductor increases the impedance of the loop, inhibits the change rate of the generated leakage current, avoids the impact of the leakage current on the devices in the photovoltaic grid-connected inverter, and further avoids the damage of the devices in the photovoltaic grid-connected inverter due to the leakage current.
[0041] Figure 2 For a second structural schematic diagram of a photovoltaic grid-connected circuit provided in the embodiment of the present application, refer to Figure 2 The photovoltaic grid-connected circuit further comprises a filtering module 3, one end of the filtering module 3 is connected to the output end of the inverter module 2, and the other end of the filtering module 3 is connected to the power grid, and the filtering module 3 is used to suppress the output electromagnetic interference of the inverter module 2.
[0042] In a feasible embodiment of the present application, the filtering module 3 comprises an EMI filtering circuit, the EMI filtering circuit comprises an X capacitor, a Y capacitor, a common-mode inductor and a differential-mode inductor, the common-mode inductor and the differential-mode inductor are both connected in series on the live wire and the zero wire of the power grid, the X capacitor is connected across the live wire and the zero wire of the power grid, the Y capacitor is connected in parallel with the X capacitor, the Y capacitor is connected across the live wire and the ground PE and the zero wire and the ground PE of the power grid respectively, and the EMI filtering circuit is used to suppress common-mode interference and differential-mode interference.
[0043] Figure 3 For a third structural schematic diagram of a photovoltaic grid-connected circuit provided in the embodiment of the present application, refer to Figure 3 The circuit topology of the inverter module 2 is a non-isolated inverter topology circuit, and further, the circuit topology of the non-isolated inverter topology circuit is a Heric topology.
[0044] Specifically, in some specific examples, the circuit topology of the inverter module 2 is a Heric topology, and the inverter module 2 includes a first IGBT tube S1, a second IGBT tube S2, a third IGBT tube S3, a fourth IGBT tube S4, a fifth IGBT tube S5, a sixth IGBT tube S6, a third inductor L3, and a fourth inductor L4.
[0045] The emitter of the first IGBT tube S1 is connected to the collector of the second IGBT tube S2, the emitter of the third IGBT tube S3 is connected to the collector of the fourth IGBT tube S4, and the emitter of the fifth IGBT tube S5 is connected to the emitter of the sixth IGBT tube S6; the collector of the first IGBT tube S1 and the collector of the second IGBT tube S2 are connected to one end of a capacitor C, and the collector of the third IGBT tube S3 and the collector of the fourth IGBT tube S4 are connected to the other end of the capacitor C; the collector of the fifth IGBT tube S5 is connected between the emitter of the first IGBT tube S1 and the collector of the second IGBT tube S2, and the collector of the sixth IGBT tube S6 is connected between the emitter of the third IGBT tube S3 and the collector of the fourth IGBT tube S4; the collector of the fifth IGBT tube S5 is further connected to one end of the third inductor L3, and the collector of the sixth IGBT tube S6 is further connected to one end of the fourth inductor L4; the other end of the third inductor L3 and the other end of the fourth inductor L4 are both connected to the filter module 3.
[0046] In some scenarios, when the negative output end PV- of the photovoltaic panel is struck by lightning, the additional input lightning energy forms a leakage current that surges into the inverter module 2, which impacts the power tube devices in the inverter module 2. Similarly, due to the provision of the second inductor L2 in the technical solution provided by the present application, the leakage current formed by the lightning energy will necessarily pass through the second inductor L2, thereby avoiding the impact of the leakage current formed by the lightning energy on the power tube devices in the inverter module 2.
[0047] However, it is difficult to completely release the leakage current formed by the lightning energy by only the buffering of the second inductor L2, and therefore, in a feasible embodiment of the present application, the transformer module 1 further includes a lightning protection unit 4, the first end of the lightning protection unit 4 is connected between the first inductor L1 and the positive output end PV+ of the photovoltaic panel, the second end of the lightning protection unit 4 is connected between the second inductor L2 and the negative output end PV- of the photovoltaic panel, the third end of the lightning protection unit 4 is connected to the ground PE, and the lightning protection unit 4 is used to release the lightning energy to the ground PE when the lightning energy acts on the output end of the photovoltaic panel.
[0048] Figure 4 A fourth structural schematic diagram of a photovoltaic grid-connected circuit provided by an embodiment of the present application is shown in FIG. 4, which is described with reference to FIG. 4. Figure 4The lightning protection unit 4 is arranged between the positive output terminal PV+ of the photovoltaic panel, the negative output terminal PV- of the photovoltaic panel and the ground wire PE. When the lightning energy acts on the negative output terminal PV- of the photovoltaic panel, part of the lightning energy is released to the ground wire PE through the lightning protection unit 4, and the other part will not directly impact the power tube device in the inverter module 2 due to the buffering of the second inductor L2. Through the lightning protection unit 4, the lightning energy is released as much as possible, and further protection is realized for the photovoltaic grid-connected circuit.
[0049] With reference to Figure 5 The lightning protection unit 4 includes a first voltage-dependent resistor RV1, a second voltage-dependent resistor RV2 and a third voltage-dependent resistor RV3. One end of the first voltage-dependent resistor RV1 is connected between the first inductor L1 and the positive output terminal PV+ of the photovoltaic panel as a first end of the lightning protection unit 4. The other end of the first voltage-dependent resistor RV1 is connected to one end of the second voltage-dependent resistor RV2 and one end of the third voltage-dependent resistor RV3, respectively. The other end of the second voltage-dependent resistor RV2 is connected between the second inductor L2 and the negative output terminal PV- of the photovoltaic panel as a second end of the lightning protection unit 4. The other end of the third voltage-dependent resistor RV3 is connected to the ground wire PE as a third end of the lightning protection unit 4.
[0050] Specifically, when the lightning energy acts on the negative output terminal PV- of the photovoltaic panel, the voltage across the second voltage-dependent resistor RV2 and the third voltage-dependent resistor RV3, and the resistance of the second voltage-dependent resistor RV2 and the third voltage-dependent resistor RV3 rapidly decreases, and the second voltage-dependent resistor RV2 and the third voltage-dependent resistor RV3 are equivalent to a conductor. At this time, the lightning energy is released to the ground through the negative output terminal PV- of the photovoltaic panel-second voltage-dependent resistor RV2-third voltage-dependent resistor RV3-ground wire PE.
[0051] At the same time, when the lightning energy acts on the positive output terminal PV+ of the photovoltaic panel, the voltage across the first voltage-dependent resistor RV1 and the third voltage-dependent resistor RV3, and the resistance of the first voltage-dependent resistor RV1 and the third voltage-dependent resistor RV3 rapidly decreases, and the first voltage-dependent resistor RV1 and the third voltage-dependent resistor RV3 are equivalent to a conductor. At this time, the lightning energy is released to the ground through the positive output terminal PV+ of the photovoltaic panel-first voltage-dependent resistor RV1-third voltage-dependent resistor RV3-ground wire PE.
[0052] With reference to Figure 6The lightning protection unit 4 includes a fourth voltage-dependent resistor RV4, a fifth voltage-dependent resistor RV5 and a gas discharge tube GAS, one end of the fourth voltage-dependent resistor RV4 is connected between the first inductor L1 and the positive output terminal PV+ of the photovoltaic panel as a first end of the lightning protection unit 4, the other end of the fourth voltage-dependent resistor RV4 is connected to one end of the fifth voltage-dependent resistor RV5 and one end of the gas discharge tube GAS respectively, the other end of the fifth voltage-dependent resistor RV5 is connected between the second inductor L2 and the negative output terminal PV- of the photovoltaic panel as a second end of the lightning protection unit 4, and the other end of the gas discharge tube GAS is connected to the ground wire PE as a third end of the lightning protection unit 4.
[0053] Specifically, the gas discharge tube GAS is filled with inert gas, a voltage is applied to both ends of the gas discharge tube GAS, a non-uniform electric field is generated in the gas discharge tube GAS, under the action of the electric field, the gas in the tube begins to ionize, and the gas discharge tube GAS is equivalent to a wire.
[0054] When the lightning strike energy acts on the negative output terminal PV- of the photovoltaic panel, the voltage acts on both ends of the gas discharge tube GAS and the fifth voltage-dependent resistor RV5, and the gas discharge tube GAS and the fifth voltage-dependent resistor RV5 are equivalent to a wire. At this time, the lightning strike energy is released to the ground through the negative output terminal PV- of the photovoltaic panel, the gas discharge tube GAS, the fifth voltage-dependent resistor RV5 and the ground wire PE.
[0055] At the same time, when the lightning strike energy acts on the positive output terminal PV+ of the photovoltaic panel, the voltage acts on both ends of the gas discharge tube GAS and the fourth voltage-dependent resistor RV4, and the gas discharge tube GAS and the fourth voltage-dependent resistor RV4 are equivalent to a wire. At this time, the lightning strike energy is released to the ground through the positive output terminal PV+ of the photovoltaic panel, the gas discharge tube GAS, the fourth voltage-dependent resistor RV4 and the ground wire PE.
[0056] Figure 7 A structural schematic diagram of a photovoltaic grid-connected inverter provided by the embodiment of the application is shown in Figure 7 The application further provides a photovoltaic grid-connected inverter, which comprises the photovoltaic grid-connected circuit according to any one of the above embodiments.
[0057] It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order
[0058] The above description is that of current embodiments of the application. Various modifications and changes can be made thereto without departing from the spirit and scope of the application as set forth. The scope of the application is not to be limited to the exact details shown above.
Claims
1. A photovoltaic grid-tie circuit, characterized by, The photovoltaic grid-connected circuit comprises a voltage conversion module and an inverter module, an input end of the voltage conversion module is connected to an output end of a photovoltaic panel, an output end of the voltage conversion module is connected to an input end of the inverter module, and an output end of the inverter module is connected to a power grid. The voltage conversion module comprises a first inductor, a second inductor, a switch tube, a diode and a capacitor, one end of the first inductor is connected to a positive output end of the photovoltaic panel, the other end of the first inductor is connected to an anode of the diode and a first end of the switch tube respectively, a cathode of the diode is connected to one end of the capacitor and the input end of the inverter module respectively, the other end of the capacitor is connected to one end of the second inductor, a second end of the switch tube and the input end of the inverter module respectively, and the other end of the second inductor is connected to a negative output end of the photovoltaic panel.
2. The photovoltaic grid-tie circuit of claim 1, wherein, The switch tube is any one of a power field effect transistor, a gallium nitride field effect transistor, a silicon carbide field effect transistor or an insulated gate bipolar transistor.
3. The photovoltaic grid-tie circuit of claim 1, wherein, The photovoltaic grid-connected circuit further comprises a filter module, one end of the filter module is connected to the output end of the inverter module, the other end of the filter module is connected to the power grid, and the filter module is used for suppressing electromagnetic interference of the output end of the inverter module.
4. The photovoltaic grid-tie circuit of claim 3, wherein, The filter module comprises an EMI filter circuit, the EMI filter circuit comprises an X capacitor, a Y capacitor, a common-mode inductor and a differential-mode inductor, the common-mode inductor and the differential-mode inductor are connected in series on a live wire and a zero wire of the power grid, the X capacitor is connected across the live wire and the zero wire of the power grid, the Y capacitor is connected in parallel with the X capacitor, the Y capacitor is connected across the live wire and a ground wire and the zero wire and the ground wire respectively, and the EMI filter circuit is used for suppressing common-mode interference and differential-mode interference.
5. The photovoltaic grid-tie circuit of claim 1, wherein, The voltage conversion module further comprises a lightning protection unit, a first end of the lightning protection unit is connected between the first inductor and the positive output end of the photovoltaic panel, a second end of the lightning protection unit is connected between the second inductor and the negative output end of the photovoltaic panel, and a third end of the lightning protection unit is connected to a ground wire, and the lightning protection unit is used for releasing lightning energy to the ground wire when the lightning energy acts on the output end of the photovoltaic panel.
6. The photovoltaic grid-tie circuit of claim 5, wherein, The lightning protection unit comprises a first voltage-dependent resistor, a second voltage-dependent resistor and a third voltage-dependent resistor, one end of the first voltage-dependent resistor is connected between the first inductor and the positive output end of the photovoltaic panel as the first end of the lightning protection unit, the other end of the first voltage-dependent resistor is connected to one end of the second voltage-dependent resistor and one end of the third voltage-dependent resistor respectively, the other end of the second voltage-dependent resistor is connected between the second inductor and the negative output end of the photovoltaic panel as the second end of the lightning protection unit, and the other end of the third voltage-dependent resistor is connected to the ground wire as the third end of the lightning protection unit.
7. The photovoltaic grid-tie circuit of claim 5, wherein, The lightning protection unit comprises a fourth voltage-dependent resistor, a fifth voltage-dependent resistor and a gas discharge tube, one end of the fourth voltage-dependent resistor is connected between the first inductor and the positive output terminal of the photovoltaic panel as a first end of the lightning protection unit, the other end of the fourth voltage-dependent resistor is connected to one end of the fifth voltage-dependent resistor and one end of the gas discharge tube respectively, the other end of the fifth voltage-dependent resistor is connected between the second inductor and the negative output terminal of the photovoltaic panel as a second end of the lightning protection unit, and the other end of the gas discharge tube is connected to the ground wire as a third end of the lightning protection unit.
8. The photovoltaic grid-tie circuit of claim 1, wherein, The circuit topology of the inverter module comprises a non-isolated inverter topology circuit.
9. The photovoltaic grid-tie circuit of claim 8, wherein, The circuit topology of the non-isolated inverter topology circuit comprises a Heric topology.
10. A photovoltaic grid-tied inverter, characterized by, The photovoltaic grid-connected inverter comprises the photovoltaic grid-connected circuit according to any one of claims 1-9.