大功率整流电路直流侧非特征谐波的分析

Abnormal harmonic analysis of DC side in high power rectifying system

当前大功率高稳定度电源仍然采用晶闸管相控整流技术,但是在实际运行中总是存在一定的低次谐波分量,给滤波器的选择以及谐波抑制造成一定的困难。因此有必要对谐波产生的机理及其含量有一个准确的认识。利用用于对整流设备稳态工作进行谐波分析的开关函数法对整流器在几种非理想情况下的直流侧非特征谐波进行了分析,从而得出了在各种不同运行情况下直流侧非特征谐波的具体表达式。推导的结论为以后的谐波抑制提供理论依据和计算基础。同时对于高压直流输电谐波分析也具有参考意义。

Line-commutated converters are widely used to acquire highly-stability power supply at the present time. But there inescapabily exists some low order harmonics in DC side during its operation, which are regarded as abnormal harmonics, and makes the choosing and designing of the filter difficult. It is essential to realize the yield mechanics of the abnormal harmonics. In this paper, the method which is based on the switching function is used to analyse the harmonic of the rectifier under stable state. By this method, abnormal harmonics which occur under some non-ideal operating condition, such as the firing angle is delayed, the voltage in the AC side is distorted by the harmonic or by the unbalanced parameter of the apparatus, can be analyzed. Further more, the expression of the low order harmonics can be acquired in different operating conditions. So the component of the abnormal harmonic in the out voltage can be calculated. Based on the conclusion which supplies the theoretic verity, harmonic restraining and the design of the filter will be easy. And the conclusions play a very important role in analyzing harmonic in the DC side of HVDC system.