Secondary current ripple suppression method based on active large capacitor

Abstract

The invention discloses a secondary current ripple suppression method based on active large capacitors, which comprises a ripple suppression circuit, the ripple suppression circuit comprises an active large capacitor Ceq1 and an active large capacitor Ceq2 which can be connected in series to work, and the two ends of the active large capacitor Ceq1 and the active large capacitor Ceq2 which are connected in series are connected in parallel to the two ends of a direct current bus; according to the ripple suppression circuit, the instantaneous power of the ripple suppression circuit and the secondary pulse power on the direct current bus are equal in size and complementary in phase, so that absorption of secondary ripple current is achieved. The ripple suppression circuit has the advantages that secondary current ripples are absorbed, the size of an energy storage element required in the ripple suppression circuit is reduced, the use of an electrolytic capacitor is avoided, the power density of a system is improved, and the service life of the system is prolonged.

Description

technical field [0001] The invention relates to the technical field of power quality, in particular to a secondary current ripple suppression method based on an active large capacitor. Background technique [0002] With the development of fully-controlled power switching semiconductor device technology, power electronic conversion technology has also developed, and converters based on pulse width modulation (PWM) control have emerged, the most common being PWM rectifier converters. This can work both in the rectification state and in the inverter state. In an AC-DC microgrid system with a single-phase PWM rectifier converter, no matter what state the converter is in, the sinusoidal current and voltage on the AC side will generate a secondary pulsating power twice the frequency of the fundamental frequency. Power affects the DC side at the same time. Taking the inverter state as an example, most of the distributed power sources are in the voltage source output mode, that is...

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Problems solved by technology

[0006] The present invention provides a secondary current ripple suppression method based on an active large capacitor, which overcomes the need for a large volume of capacitor, large volume of the entire device, and low power consumption in the existing ripple suppression method described in the background art. Low density, high cost, and usually use electrolytic capacitors, short system life

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