交流励磁变速恒频发电机谐波同步消除法

Synchronous Filter Method for AC Excited Variable Speed Constant Frequency Generators

目前大容量的交流励磁变速恒频水轮发电机,仍然采用晶闸管换流的交?交变频器提供励磁。由于这种交-交变频器输出电压中含有大量的谐波,导致发电机输出电压质量无法满足实际需求。本文针对采用余弦交点法控制的交?交变频器,通过对输出电压波形的基本结构进行分析,找出谐波的内在规律。并以有源滤波为基础,提出了谐波同步消除方法,与现有的各种有源滤波方法相比,其算法简单、效果明显,即使为发电机提供直流励磁时,也可以达到明显的滤波效果,从而有效提高了发电机输出的电能质量。

Large capacity variable speed constant frequency generator （VSCFG） adopts cycloconverter as its exciting device, but power quality of VSCFG cannot meet the need of power system because of harmonics in the output voltage of cycloconverter, so how to reduce harmonics is an important problem for VSCFG. A new active power filter method named synchronous filter method was presented in this paper, which based on the analysis of output voltage wave forms. Compared with other methods, synchronous filtering method has the characters of simple calculation and obvious effect. This method may be adapted to the situation that the output frequency is changed continually and even the output is DC. It can improve the output voltage quality of an AC excited variable speed constant frequency generator obviously.