Research on a series active filter aiming at voltage flicker and harmonic compensation

点击翻译按钮获取中文摘要

A specially designed twelve-pulse thyristor rectifier of 5-8MVA is required as a low-voltage high-current dc power supply for super-conductive material tests. It is, however, too susceptible to low frequency variation of the utility voltage, or to the so-called "flicker" to generate a strong magnetic field with high stability.In this research, a new flicker and harmonic compensator based on the combination of a small-rated series active filter and a conventional shunt active filter was developed and tested by the authors. The main purpose of the series active filter is to remove voltage susceptibility to flicker from the large-rated thyristor rectifier. The following items are clarified by analysis and experiment.1.It was verified by experiment that the series active filter has the capability of reducing voltage flicker in a range of 1-20Hz into 1/10. The experimental result agreed well with the analytical one.2.It was verified by experiment that the series active filter has the supplementary value-added capability of forcing all the harmonic current produced by the thyristor rectifier to flow into the shunt passive filter connected in parallel with the thyristor rectifier.3.It was pointed out by analysis and experiment that No series or parallel resonance occurs between the shunt passive filter and line inductance because the series active filter acts as a damping resistor for harmonics.