高速磁悬浮系统谐波检测的小波降噪仿真分析

高速磁悬浮列车是一种新型的谐波源,采用半控双三相12脉冲整流器,所产生的谐波以23次、25次高频谐波为主,这些高频谐波对磁悬浮列车的安全稳定运行造成了很大的危害。准确地分析、检测出高速磁悬浮列车分高频谐波具有非常重要的意义。针对高速磁悬浮列车牵引供电系统谐波的特征,分析了小波降噪在高速磁悬浮列车牵引供电系统的应用并进行了仿真;由于在小波降噪中不同的阈值适应的信号特征不同,采用多种小波阈值对牵引供电系统谐波信号进行降噪,并从中选择了最优的降噪阈值,达到对信号的优化处理。仿真结果表明,高速磁悬浮列车牵引供电系统谐波信号的最优阈值为sqrt(2log(length(X)))阈值,它降噪后可使信号中的谐波成分有明显的降低。

De-noise Simulation on Harmonic Measurement of High-speed Maglev

As a new harmonics resource, High-speed maglev adopts the semi-control double three-phase 12-pulse rectifier, whose high frequency harmonics, which mainly is 23 times and 25 times harmonics, do great harm to the maglev movement safely and stably. It is very important to analysis and measure the high frequency harmonics precisely. Due to the different wavelet threshold fit for the different characteristic of signal, various wavelet de-noise threshold was used to decline the harmonics of signal and the best threshold was choose, meanwhile, simulation was carried on. The results express sqrt(2log(length(X))) threshold ,which declined the noise mostly ,is the best threshold.