A Study of Active Power Filters Applying Space Vectors and their Compensation Algorithm

为了抑制静态变流器产生的谐波，近年来人们对有源电力滤波器进行了研究和开发。值得一提的是，利用功率晶体管和闸通晶闸管等开关器件的有源电力滤波器得到了广泛的关注，在容量和开关性能方面都取得了显著的进步。在本研究中，应用空间矢量理论，提出了基于瞬时无功功率的有源电力滤波器补偿算法。这与传统的补偿算法在原理上有很大的不同，从而在暂态下具有更好的补偿特性。构建了额定功率为7kVA的实验性有源电力滤波器。电源电路由四串电压源PWM变换器组成，采用24个功率晶体管。多路变流器的主要目的是在不增加开关频率的情况下抑制开关操作产生的谐波。实验验证了有源电力滤波器的有效性。以额定功率为20kVA的三相可控硅桥式变换器为例进行了谐波电流发生器的研究。应用该理论提出的补偿算法，不仅可以完全消除稳态谐波电流，而且可以完全消除暂态谐波电流。有源电力滤波器的总效率为90- 92%，包括多个变流器的损耗。

In recent years, active power filters have been studied and developed to suppress harmonics generated by static power converters. Notably, attention has been paid to the active power filter using switching devices such as power transistors and gate-turn-off thyristors, which have made remarkable progress in capacity and switching performance.In this study, the compensation algorithm of the active power filter is proposed on the basis of the instantaneous reactive power applying space vector theory. This is quite different in principle from the conventional compensation algorithm, thus giving better compensation characteristics in transient states. An experimental active power filter was constructed, of rating 7kVA. The power circuit consisted of quad-series voltage source PWM converters using 24 power transistors. The main purpose of the mutiple converters was to suppress the harmonics caused by the switching operation without increasing the switching frequency.The validity of the active power filter was comfirmed experimentally. A three-phase thyristor bridge converter of rating 20kVA was used as an example of harmonic current generators. It was verified that the harmonic current can be fully eliminated not only in steady state but also in transient states, applying the compensation algorithm developed in this theory. The total efficiency of the active power filter was 90-92 percent, including the loss of the multiple converters.