一种低电磁干扰载波斜率随机分布脉宽调制技术

A Random Slope PWM With Low Electromagnetic Interference

针对固定载波脉宽调制技术输出电压谐波在载频及其倍频附近集中的问题,提出了一种载波斜率随机分布脉宽调制技术,无需滤波电路即可分散谐波能量,减少谐波突出幅值给电力系统带来的电磁干扰问题。在分析固定载波脉宽调制谐波特性的基础上,类推出随机载波脉宽调制技术的可行性;从随机信号的数理统计参量出发构建了载波斜率随机分布脉宽调制数学模型,对输出电压功率谱进行推导,阐释了载波斜率随机分布脉宽调制技术分散谐波能量的原理,并对影响谐波能量分布的参数进行了分析;最后,仿真和实验表明载波斜率随机分布脉宽调制输出电压谐波能量更为分散、平缓,对于中大容量电力系统中谐波处理具有重要意义。

To deal with the unexpected high harmonics produced by the fixed cartier pulse width modulation （FCPWM） accumulated at the carder frequency and its multiples, this paper has proposed a random slope pulse width modulation （RSPWM） to disperse harmonic energy and reduce the electromagnetic interference （EMI）. Based on the analysis of harmonics characteristics of the FCPWM, the random cartier pulse width modulation （RCPWM） proves to be feasible, and a mathematical model for RCPWM, that is, RSPWM is established according to the theory of statistical signals. The model is used to analyze the power spectral density of output voltage and to expound the principle of dispersing the harmonics by use of the RSPWM were discussed as well as the parameter influencing the harmonic energy distribution. Finally, simulations and experiments show that the RSPWM have an advantage in dispersing harmonics, which is of great value to the disposal of harmonics in a middle or large-capacity power system.