Method for controlling single-phase non-isolated photovoltaic inverter with follow current clamping switch

Abstract

The invention provides a method for controlling a single-phase non-isolated photovoltaic inverter with a follow current clamping switch. The method for controlling the single-phase non-isolated photovoltaic inverter with the follow current clamping switch comprises the steps that two-section control is conducted on switch tubes in the inverter; the gate source control waveform of the first switch tube is made to the same as that of the fourth switch tube, wherein the gate source control waveforms are SPWM waveforms in the half positive cycle during which current is output by the inverter, and the gate source control waveforms are zero waveforms in the half negative cycle during which current is output by the inverter; the gate source control waveform of the second switch tube is made the same as that of the third switch tube, wherein the gate source control waveforms are zero waveforms in the half positive cycle during which current is output by the inverter, and the gate source control waveforms are SPWM waveforms in the half negative cycle during which current is output by the inverter; the gate source control waveform of the fifth switch tube and the gate source control waveform of the sixth switch tube are made to be complementary with the gate source control waveform of the first switch tube and the gate source control waveform of the fourth switch tube in the half positive cycle during which current is output by the inverter and be complementary with the gate source control waveform of the second switch tube and the gate source control waveform of the third switch tube in the half negative cycle during which current is output by the inverter. By the adoption of the method for controlling the single-phase non-isolated photovoltaic inverter with the follow current clamping switch, the conversion efficiency of the non-isolated photovoltaic inverter can be improved, and the common-mode characteristic of the non-isolated photovoltaic inverter is improved.

Description

technical field [0001] The invention relates to the technical field of power electronic DC-AC conversion, in particular to a control method for a single-phase non-isolated photovoltaic inverter with a freewheeling clamp switch, which is suitable for photovoltaic power generation occasions. Background technique [0002] Photovoltaic grid-connected inverters require high efficiency, low cost, and can withstand the adverse effects of large output voltage fluctuations of photovoltaic cells, and their AC output must also meet high power quality. [0003] According to whether the inverter has an isolation transformer, it can be divided into isolation type and non-isolation type. The isolated photovoltaic inverter realizes the electrical isolation of the power grid and the battery panel, and ensures the safety of people and equipment, but it is bulky, expensive, and the system conversion efficiency is low. The non-isolated photovoltaic inverter structure does not contain a transfo...

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Problems solved by technology

However, the removal of the transformer leads to an electrical connection between the input and output. Due to the existence of the capacitance of the battery board to the ground, the common mode leakage ...

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