A surge protection device for a micro-inverter

Abstract

The utility model relates to a kind of anti-surge device of micro inverter, belong to photovoltaic power generation technical field.The anti-surge device of micro inverter of the utility model, it includes a filter module and a multistage surge protection module.Filter module is used to filter the high-frequency harmonic in the output current of the micro inverter;Multistage surge protection module is connected in parallel with the filter module, for inhibiting common mode and differential mode surge overvoltage.The structure of the anti-surge device of micro inverter is compact, protection is comprehensive, reliability is high, and can be used to protect micro inverter from damage when suffering extreme surge, prolong service life.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic power generation technology, and particularly to the field of inverter technology, specifically a surge protection device for a micro inverter. Background Technology

[0002] As a core component of distributed photovoltaic power generation systems, the reliability of microinverters directly affects the lifespan and safety of the entire system. In the operating environment, microinverters may be subject to surge overvoltages and electromagnetic interference caused by lightning strikes, grid operations, and other factors. Single overvoltage protection devices (such as varistors) have limited response characteristics or current-carrying capacity, making it difficult to effectively protect the expensive power devices and control units inside the inverter under extreme surges, posing a significant risk of inverter equipment damage.

[0003] Therefore, how to provide an integrated surge protection device that can simultaneously achieve efficient filtering and multi-level, coordinated surge protection has become an urgent problem to be solved in this field. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an integrated surge protection device for microinverters that can simultaneously achieve efficient filtering and multi-level, coordinated surge protection, ensuring high reliability and long lifespan of microinverters in complex power grid environments.

[0005] To achieve the above objectives, the surge protection device of this utility model for a micro inverter is connected between the phase line L1 and neutral line N1 of the AC output terminal of the micro inverter and the live line Grid L and neutral line Grid N of the power grid. The device includes:

[0006] A filtering module is used to filter out high-frequency harmonics in the output current of the microinverter;

[0007] A multi-stage surge protection module is connected in parallel with the aforementioned filter module to suppress common-mode and differential-mode surge overvoltages.

[0008] In the surge protection device of this micro-inverter, the filtering module includes an inductor L2 and a capacitor C2. The inductor L2 is connected in series between the phase line L1 and neutral line N1 of the AC output terminal of the micro-inverter and the live line GridL and neutral line GridN of the power grid. The capacitor C2 is connected between the phase line L1 and neutral line N1 of the AC output terminal. The inductor L2 and the capacitor C2 constitute an LC low-pass filter circuit.

[0009] In the surge protection device of this micro-inverter, the surge protection module includes a primary protection unit and a secondary protection unit. The primary protection unit is connected between the live wire Grid L and the neutral wire Grid N of the power grid to achieve overvoltage protection, prevent excessive voltage from being transmitted to the power grid side, and suppress common-mode surges. The secondary protection unit is connected between the phase line L1 and the neutral line N1 of the AC output terminal and is connected in parallel with capacitor C2 to suppress rapid differential-mode voltage spikes.

[0010] In the surge protection device of this micro inverter, the primary protection unit includes a discharge tube GAP2 and varistors RV1 and RV2. One end of the varistors RV1 and RV2 are connected in parallel to the neutral line Grid N of the power grid, and the other end is connected to one end of the discharge tube GAP2. The other end of the discharge tube GAP2 is connected to the live line Grid L of the power grid.

[0011] In the surge protection device of this micro inverter, the secondary protection unit includes a transient voltage suppression diode TVS1, which is connected between the phase line L1 and the neutral line N1 of the AC output terminal.

[0012] The surge protection device for a microinverter employing this invention includes a filter module and a multi-stage surge protection module. The filter module filters out high-frequency harmonics in the output current of the microinverter; the multi-stage surge protection module is connected in parallel with the filter module to suppress common-mode and differential-mode surge overvoltages. This surge protection device for microinverters is compact, provides comprehensive protection, and has high reliability. It can be used to protect microinverters from damage when subjected to extreme surges, extending their service life. Attached Figure Description

[0013] Figure 1 This is a structural schematic diagram of the surge protection device for the micro inverter of this utility model. Detailed Implementation

[0014] In order to better understand the technical content of this utility model, the following embodiments are provided for detailed description.

[0015] Please see Figure 1 The diagram shown is a structural schematic of the surge protection device for the micro inverter of this utility model.

[0016] In one implementation, such as Figure 1 As shown, the surge protection device of the microinverter is connected between the phase line L1 and neutral line N1 of the AC output terminal of the microinverter and the live line Grid L and neutral line Grid N of the power grid. The device is characterized by comprising:

[0017] A filtering module is used to filter out high-frequency harmonics in the output current of the microinverter;

[0018] A multi-stage surge protection module is connected in parallel with the aforementioned filter module to suppress common-mode and differential-mode surge overvoltages.

[0019] The filtering module includes an inductor L2 and a capacitor C2. The inductor L2 is connected in series between the phase line L1 and neutral line N1 of the AC output terminal of the micro-inverter and the live line Grid L and neutral line Grid N of the power grid. The capacitor C2 is connected between the phase line L1 and neutral line N1 of the AC output terminal. The inductor L2 and the capacitor C2 constitute an LC low-pass filter circuit.

[0020] In a preferred embodiment, the surge protection module includes a primary protection unit and a secondary protection unit. The primary protection unit is connected between the live wire Grid L and the neutral wire Grid N of the power grid to achieve overvoltage protection, prevent excessive voltage from being transmitted to the power grid side, and suppress common-mode surges. The secondary protection unit is connected between the phase line L1 and the neutral line N1 of the AC output terminal and is connected in parallel with capacitor C2 to suppress rapid differential-mode voltage spikes.

[0021] The primary protection unit includes a discharge tube GAP2 and varistors RV1 and RV2. One end of the varistors RV1 and RV2 are connected in parallel to the neutral wire Grid N of the power grid, and the other end is connected to one end of the discharge tube GAP2. The other end of the discharge tube GAP2 is connected to the live wire Grid L of the power grid.

[0022] The secondary protection unit includes a transient voltage suppression diode TVS1, which is connected between the phase line L1 and the neutral line N1 of the AC output terminal.

[0023] In practical applications, this utility model includes: micro inverter output terminals L1 and N1, common mode inductor L2, capacitor C2, TVS diode TVS1, varistors RV1 and RV2, discharge tube GAP2, and grid interfaces Grid L and Grid N.

[0024] The AC output from the micro-inverter passes through an inductor L2 connected in series. A capacitor C2 is connected in parallel between line L after inductor L2 and the neutral line N, together forming an LC filter.

[0025] A multi-stage surge protection module is connected in parallel after the filter module. Varistors RV1 and RV2 are connected in parallel, then in series with discharge diode GAP2, and finally connected between power line L and line N to form a first-stage protection circuit. This circuit absorbs extremely large surge energy. A TVS diode, TVS1, is connected between line L and line N to clamp rapid voltage spikes.

[0026] During operation, when a surge occurs, the component with the highest energy and relatively slow velocity is first responded to and absorbed by the varistors RV1 and RV2 and the discharge tube; the remaining medium-energy residual voltage is clamped by the diode TVS1. Multi-level protection is activated step by step, working together to complete surge suppression.

[0027] This invention utilizes a two-stage collaborative protection mode, employing a discharge tube, varistor, and TVS diode design to achieve full-spectrum, blind-zone-free protection against lightning surges. Response speeds range from microseconds to picoseconds, and current discharge capacity extends from the kA level to hundreds of amperes, significantly improving the surge withstand capability of the equipment. Integrating efficient filtering and comprehensive surge protection into a compact interface circuit simplifies system design, enhances operational flexibility, reliably protects the core circuitry of the micro-inverter, and extends system lifespan.

[0028] The surge protection device for a microinverter employing this invention includes a filter module and a multi-stage surge protection module. The filter module filters out high-frequency harmonics in the output current of the microinverter; the multi-stage surge protection module is connected in parallel with the filter module to suppress common-mode and differential-mode surge overvoltages. This surge protection device for microinverters is compact, provides comprehensive protection, and has high reliability. It can be used to protect microinverters from damage when subjected to extreme surges, extending their service life.

[0029] In this specification, the present invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the specification and drawings should be considered illustrative rather than restrictive.

Claims

1. A surge protection device for a microinverter, said device being connected between the phase line L1 and neutral line N1 of the AC output terminal of the microinverter and the live line Grid L and neutral line Grid N of the power grid, characterized in that, The device includes: A filtering module is used to filter out high-frequency harmonics in the output current of the microinverter; A multi-stage surge protection module is connected in parallel with the aforementioned filter module to suppress common-mode and differential-mode surge overvoltages.

2. The surge protection device for a micro inverter according to claim 1, characterized in that, The filtering module includes an inductor L2 and a capacitor C2. The inductor L2 is connected in series between the phase line L1 and neutral line N1 of the AC output terminal of the micro inverter and the live line Grid L and neutral line Grid N of the power grid. The capacitor C2 is connected between the phase line L1 and neutral line N1 of the AC output terminal. The inductor L2 and the capacitor C2 constitute an LC low-pass filter circuit.

3. The surge protection device for a micro inverter according to claim 2, characterized in that, The surge protection module includes a primary protection unit and a secondary protection unit. The primary protection unit is connected between the live wire Grid L and the neutral wire Grid N of the power grid to realize overvoltage protection, prevent excessive voltage from being transmitted to the power grid side, and suppress common-mode surges. The secondary protection unit is connected between the phase line L1 and the neutral line N1 at the AC output terminal, and is connected in parallel with capacitor C2 to suppress rapid differential mode voltage spikes.

4. The surge protection device for a micro inverter according to claim 3, characterized in that, The primary protection unit includes a discharge tube GAP2 and varistors RV1 and RV2. One end of the varistors RV1 and RV2 are connected in parallel to the neutral wire GridN of the power grid, and the other end is connected to one end of the discharge tube GAP2. The other end of the discharge tube GAP2 is connected to the live wire GridL of the power grid.

5. The surge protection device for a micro inverter according to claim 3, characterized in that, The secondary protection unit includes a transient voltage suppression diode TVS1, which is connected between the phase line L1 and the neutral line N1 of the AC output terminal.

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