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

超导材料试验需要专门设计5-8MVA的十二脉冲晶闸管整流器作为低压大电流直流电源。然而，它太容易受到公用电压的低频变化，或所谓的“闪烁”，以产生具有高稳定性的强磁场。在本研究中，作者开发并测试了一种基于小额定串联有源滤波器和传统并联有源滤波器相结合的新型闪变谐波补偿器。串联有源滤波器的主要目的是消除大额定值可控硅整流器对闪变的电压敏感性。通过分析和实验，阐明了以下几点。实验证明，串联有源滤波器具有将1 ~ 20hz范围内的电压闪变减小到1/10的能力。实验结果与分析结果吻合较好。通过实验验证，串联有源滤波器具有补充增值能力，可以将可控硅整流器产生的谐波电流全部流入与可控硅整流器并联连接的并联无源滤波器。通过分析和实验指出，并联无源滤波器与线路电感之间不会发生串联或并联谐振，因为串联有源滤波器起到了谐波阻尼电阻的作用。

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.