11相无刷励磁机故障工况的谐波分析

Harmonic Analysis of the Fault Cases in 11-Phase Brushless Exciter Based on FFT

采用快速傅里叶变换(FFT),分析11相无刷励磁机样机故障工况的谐波问题,给出输出负载电压的直流分量、基波和25次以下的谐波计算结果.结果表明,断相故障下,负载电压各次谐波有相似的变化规律,但断开的相数不同,总谐波畸变率不相同;一相断开运行,负载电压与一个二极管支路断开负载电压的谐波变化规律不同;二极管支路短路时,负载电压总谐波畸变率相当严重.

This paper analyzes the harmonic of fault cases of a ll-phase brushless exciter based on FFT （fast Fourier transformation）. The DC component and AC components till 25th harmonic for the loaded-voltage are studied. The resuits show that the harmonics of the loaded-voltage have similar variation law with out away of different phases of bridges. But with out away of different phases of bridges, the total distorted rates of the harmonics are different. The variation laws of the harmonics for loaded-voltage with out away of one phase of bridges and with open-circuit of one of diodes are different. The total distorted rate of the harmonics is serious with short-circuit of one of diodes.