Capacitor series automatic voltage equalization circuit and its control circuit

Abstract

The invention provides a capacitor-series automatic voltage sharing circuit and a control circuit thereof. The capacitor-series automatic voltage sharing circuit comprises a power circuit, wherein thepower circuit comprises a voltage sharing circuit and an inversion circuit. The control circuit is used for completing detection and voltage sharing of an end voltage of a filtering capacitor in thepower circuit, inputting the detected voltage to a peripheral circuit for processing and feeding the processed comparison signal back to a feedback input end of a control chip in an analogue circuit,the control chip is used for processing a signal of each input port and then outputting a driving signal so as to drive an on / off state of a power device in the power circuit, energy passes through aprimary side and a secondary side of the voltage sharing circuit and is output, so that automatic voltage sharing of the filtering capacitor in the power circuit is achieved. When a plurality of filtering capacitors are connected in series in the power circuit, automatic voltage sharing of the filtering capacitors can be automatically achieved, and the capacitor-series automatic voltage sharing circuit has the characteristics of simple control, rapid response and good voltage sharing effect and can be in actual application of a half-bridge insertion plasma cutting machine.

Description

technical field [0001] The present invention relates to a voltage equalizing circuit and its control circuit in the technical field of power electronic conversion, in particular to a capacitor series automatic voltage equalizing circuit and its control circuit. Background technique [0002] In the current small and medium power applications, the half-bridge circuit has been widely used due to its simple structure, easy control, and the series connection of capacitors on the DC side to improve the withstand voltage effect. However, this circuit often uses several The filter capacitors are connected in series, and there is a problem of capacitor voltage equalization due to factors such as capacitor capacitance, leakage resistance, and circuit parameters. [0003] The hidden danger of uneven capacitor voltage cannot be ignored. If the voltage equalization effect is not good, it may lead to capacitor overvoltage breakdown, control signal deviation, output waveform distortion and...

AI Technical Summary

Problems solved by technology

However, this method increases the volume and weight of the converter, increases the cost, and cannot fundamentally ensure the voltage balance of the series capacitors, and the actual effect is not ideal.

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