对称规则SPWM的谐波分析及DSP实现

给出了一种基于DSP芯片TMS320F240的对称规则SPWM信号生成法，较为详尽地分析了SPWM信号的谐波成分、总谐波失真度及其和载波比的关系。由于只需知道采样时刻，就可确定该采样周期内脉冲信号的开关点，因此SPWM特别适合在线计算。对生成的SPWM信号进行Fourier分析，结果表明，正弦波经过该方式调制以后．输出信号中不含有直流成分；当载波比为偶数时，输出信号中不含偶次谐波；提高载波比有利于滤除高次谐波。根据以上特点，将SPWM应用到某型制冷机减振电机的驱动上，对实测的电压和电流信号进行分析，其结果与理论分析相吻合。与采用模拟信号驱动的方式进行了比较，最后给出了实验结果。

Harmonic Analysis of Symmetric Regular SPWM and Its Realization Based on DSP

SPWM signal generation method based on DSP(F240 of Ti TMS320 Family) is introduced. The harmonic analysis of the signal and the influence on THD by carrier wave ratio are also analyzed. The method is suitable for real-time realization on line, since the width of impulse can be decided within one sampling period given the sampling time. Through the Fourier analysis, it is shown that the output signal does not contain the direct current component and the even harmonics when the carry wave rate is even. The high order harmonics are in favor of elimination. The method is applied to the vibration control of a cryocooler. Comparison with direct analog drive experimental results are given. Results validates the effectiveness of the harmonic analysis.