Filter for specific frequency current bypass

Abstract

The invention provides a filter for a specific sequence current bypass. The filter comprises a main filter inducer and an auxiliary filter inducer, and is characterized by also comprising a specific frequency series resonance circuit which consists of an inducer and a capacitor, wherein the series resonance frequency of the specific frequency series resonance circuit corresponds to the frequency of ripple current which flows through the main filter inducer. By arranging the series resonance circuit which consists of the inducer and the capacitor on the current bypass and ensuring that the resonance frequency of the series resonance circuit is the same as or similar to the frequency of the ripple current which flows through the main filter inducer, or is the same as or similar to the integral multiple of the frequency of the ripple current which flows through the main filter inducer, a low impedance passage is provided for switching on and off the ripple current, so that the total capacity of the inducer is effectively reduced and additional extra reactive current is greatly reduced. Therefore, equipment cost is greatly reduced and a good technical effect is achieved.

Description

Technical field: [0001] The invention relates to a grid-connected filter, in particular to a specific-frequency current bypass filter for connecting a PWM converter device with a public grid (that is, grid-connected). Background technique: [0002] With the development of society and economy, traditional energy sources are becoming increasingly tense, and new clean energy (such as solar energy, fuel cells, wind energy, etc.) power generation technologies have attracted more and more attention. However, these renewable energy sources require DC / AC when they are connected to the grid for power generation. The converter performs DC / AC voltage conversion. At the same time, taking into account the requirements of "green" power grids, PWM (pulse width adjustment) rectification, PFC (power factor correction) circuits, active power filters and other devices are becoming more and more common. These power electronic conversion devices are generally connected to the public grid throug...

AI Technical Summary

Problems solved by technology

In the above two cases, the additional inductance does not take into account the formation of a specific frequency resonant circuit with the capacitor C, which is a low-impedance channel for the ripple current flowing through the main filter inductor; therefore, the expected small inductance cannot be achieved, and additional additional The effect of small reactive current

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