单极性弱倍频SPWM逆变器控制技术

Technology of uniplar & weak frequency multiplication in SPWM inverter

单极性倍频正弦脉宽调制（sinusoidal pulse width modulation,SPWM）驱动波半周内的矩形脉冲数为偶数（倍数）。该驱动方法在输出电压波形对应基波电压峰值的部分有一个最小的关断脉冲,当系统高功率因数时,会产生很大的损耗。针对这一问题,考虑取消在输出电压波形对应基波电压峰值处的最小关断脉冲,使驱动波半周内的矩形脉冲数为奇数,形成单极性弱倍频SPWM控制的新方法。根据现有的SPWM控制方法,建立了逆变器仿真模型,分析了单极性弱倍频控制下逆变器输出电压的谐波含量和开关器件的损耗。在理论和仿真分析的基础上搭建了硬件平台,实验验证该方法相比单极性倍频SPWM在保持谐波总含量基本不变的情况下,降低了开关损耗。实验的结果表明在新的控制方式下逆变器效率提升1.6%~2.0%。

The pulse number of the single polarity frequency doubling sine Pulse Width Modulation （ sinu- soidal pulse width modulation, SPWM） drive wave in a half weeks is even number （multiple）. The driv- ing method in the output voltage waveform corresponding to the fundamental wave voltage peak parts have a minimum shutoff pulse, when the system is a high power factor, can produce a lot of wear and tear. In order to solve this problem, considering canceling the output voltage waveform corresponding to the funda- mental wave voltage pulse peak in minimum cut-off, so that the number of rectangular drive pulses is odd in a half weeks, a new method of single polarity weak frequency doubling SPWM control was formed. Ac- cording to the existing SPWM control method, the inverter simulation model was established, the inverter output voltage harmonic content and the wastage of the switching devices were analyzed, under the meth- od of single polarity weak frequency doubling control. On the basis of the theory and simulation analysis the hardware platform was built, the method is verified by the experiments compared with the single frequency doubling polarity SPWM in keeping the total harmonic content is almost the same, the switching loss is reduced. The experimental results show that under the new control method to enhance the efficiency of the inverter 1.6% -2.0%.