Photovoltaic system input impedance detection circuit, method and device

Abstract

The invention discloses a photovoltaic system input impedance detection circuit method and device. The photovoltaic system input impedance detection circuit comprises a first sub-circuit, a second sub-circuit and a third sub-circuit, wherein the first sub-circuit is used for changing the internal resistance value connected into a photovoltaic system; the second sub-circuit is used for preventing current from reversely flowing into the photovoltaic inverter through the first sub-circuit; according to the invention, the first sub-circuit is arranged, and the disconnection and connection of the first sub-circuit are controlled, so that the internal resistance value connected to the photovoltaic system is changed, and the parameter data of the photovoltaic system are obtained through the operation controller, so that the input impedance of the photovoltaic system is obtained. The input impedance of the photovoltaic system is calculated, and the input impedance of the photovoltaic system can be obtained only through the combination of the first sub-circuit and the operation controller, so that the detection cost is reduced; and meanwhile, the second sub-circuit can effectively prevent the current from reversely flowing into the photovoltaic inverter through the first sub-circuit, so that the safety of the detection circuit is improved.

Description

technical field [0001] The invention relates to the technical field of photovoltaic technology, in particular to a photovoltaic system input impedance detection circuit, method and equipment. Background technique [0002] Under the background of the country's "carbon neutrality" and "carbon peaking", green energy such as wind power, photovoltaics, and energy storage have been developing vigorously. Under this general trend, photovoltaic power generation technology has become a hot spot in the development of science and technology today. In the photovoltaic power generation system, the insulation resistance of the DC side to the ground characterizes the insulation performance of the DC system. If the impedance is too low, the leakage current generated by it will pose a threat to people. Therefore, the current safety standards require that when the DC-to-ground insulation resistance is less than a certain value, the system is not allowed to operate in parallel with the grid. ...

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Problems solved by technology

Based on this, the photovoltaic inverter needs to detect the insulation resistance value of the photovoltaic system. However, in the prior art, the circuit for detecting the DC-to-ground insulation resistance of a photovoltaic system with multiple photovoltaic inverters is too complicated, and there is a reverse flow of current. In the case of a transformer, the cost is high and it is not safe

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