An Active Power Filter Device Based on Coupled Inductor

Abstract

The invention discloses an active power filter device based on a coupled inductance, which is composed of a signal acquisition module, a main control module, a drive module, a power conversion module and an LCL filter module based on a coupled inductance. The steps of extracting command current are as follows: first, extract sinωt and cosωt which are synchronized with grid A-phase voltage ua through digital phase-locked loop; secondly, transform the three-phase grid current into dqo coordinates to obtain current id, iq in dqo coordinate system , io; the third is to perform digital low-pass filtering on id and iq to extract their DC components; the fourth is to inversely transform io, sinωt and cosωt to dqo coordinates; the fifth is to perform subtraction to obtain the three-phase grid current The fundamental reactive and harmonic currents in . After hysteresis comparison control, PWM gating signals and trigger pulses are generated to control the orderly on-off of each IGBT in the power conversion module to generate PWM voltage, which is filtered by the filter module and then injected into the grid for compensation.

Description

technical field [0001] The present invention relates to the technical field of harmonic suppression and reactive power compensation, and more specifically relates to an active power filter device based on coupled inductance, which is suitable for any three-phase three-wire or three-phase four-wire power grid with nonlinear loads, as Reactive and harmonic current compensation. Background technique [0002] With the rapid development of modern industry, nonlinear loads such as high-power power electronic devices and electric arc furnaces have been widely used. At the same time, it has brought more and more serious reactive power problems and harmonic pollution to the power grid, making the voltage and current of the power grid The waveform is distorted, the power quality is degraded and the safety of the power grid is threatened. At present, harmonics have become a major public hazard to the power grid. [0003] Passive filter technology is a traditional method of harmonic c...

AI Technical Summary

Problems solved by technology

For a single-inductor first-order filter, the attenuation capability of the PWM switching ripple output by the power conversion stage is insufficient, which will cause unnecessary harmonic components in the compensation current output by the device

In order to enhance the attenuation of switching harmonics in the PWM voltage, the inductance value has to be increased, which will increase the volume and weight of the device, increase the cost of the system, and deteriorate the dynamic tracking compensation performance of the system

In order to effectively filter switching harmonics, LC or LCR filters can be introduced into parallel APFs, but due to uncertain grid impedance, LC or LCR filters are sometimes difficult to obtain ideal filtering effects

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