AC/DC converting method for eliminating working frequency ripple wave

Abstract

An AC / DC converting total power channel is separated into a main power channel and an auxiliary power channel, wherein the main power channel is a main power converting unit, completes main power transmission meeting the requirement as soon as possible and remains a working frequency ripple wave trough; and the auxiliary power channel is used for directly transferring excess energy that can not be transferred by the main power converting unit or an energy storage capacitor through an energy storage converting unit for storing energy and then duly transferring the stored energy of the energy storage capacitor to the working frequency ripple wave trough remained by the main power converting unit, therefore, the AC / DC conversion of working frequency ripple waves is realized. The invention remarkably reduces the required capacity of the energy storage capacitor, thoroughly eliminates the working frequency ripple waves, has a flexible circuit form and a wide application prospect, adapts to various power grades and control modes, and is especially suitable for AC / DC conversion with high-power factors, high reliability, high-power density and no electrolysis capacitor.

Description

【Technical field】 [0001] The invention relates to the technical field of power electronics, in particular to an AC / DC conversion method for eliminating power frequency ripple. 【Background technique】 [0002] At present, all AD / DC conversions, including the simplest diode rectification circuit and the more complex bridgeless PFC conversion, adopt the passive filtering method of paralleling large-capacity capacitors on the DC output side to reduce power frequency multiplication ripple. Wave, to provide a relatively stable output to the load. [0003] However, the prior art has the following problems: [0004] 1. Large-capacity filter capacitors can only reduce power frequency ripple, but cannot eliminate power frequency ripple. In the case of high requirements for power frequency ripple, if the method of increasing the capacity of the filter capacitor is used, the cost will increase rapidly, and if the method of post-stage power conversion regulation is used, the cost will a...

AI Technical Summary

Problems solved by technology

[0004] 1. Large-capacity filter capacitors can only reduce power frequency ripple, but cannot eliminate power frequency ripple

In the case of high requirements for power frequency ripple, if the method of increasing the capacity of the filter capacitor is used, the cost will increase rapidly, and if the method of post-stage power conversion adjustment is used, the cost will also be increased and the efficiency will be reduced.

[0005] 2. Due to the large energy storage capacity of the large-capacity filter capacitor, it may cause a large inrush current at the moment of starting up, which reduces reliability; if a soft-start circuit is used, it will increase costs and reduce efficiency

[0006] 3. At present, electrolytic capacitors are mostly used in large-capacity filter capacitors. Due to the device itself, the loss is large and the efficiency is reduced. The temperature resistance and impact current resistance of electrolytic capacitors are very poor, and they are the most easily damaged components in power electronic products. One of them reduces the reliability; the life of electrolytic capacitors is short and deteriorates rapidly with the increase of ambient temperature, which has become one of the most troublesome problems in the industry

[0007] Due to the above reasons, there have been several schemes in the industry that do not use large-capacity electrolytic capacitors, and some schemes without electrolytic capacitors for specific loads such as LEDs, but these schemes either sacrifice the PFC performance of the input side, or The ripple performance on the output side is sacrificed, or the power frequency ripple is reflected in the form of high frequency ripple. The trough of power frequency ripple generated by zero energy loss is fully compensated

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