关键词: 随机PWM, 开关频率, WELL算法, 谐波抑制

Abstract: In the consideration that random pulse position pulse width modulation (PWM) still contains discrete spectral components, a novel strategy of dual randomized modulation is presented. The proposed method is based on dual zero vector random pulse position PWM, in which zero vector is selected as V(1 1 1) when M≥0.7 and as V(0 0 0) when M<0.7, and the random variation of the pulse position and the switch frequencyis realized by increasing the switch frequency randomization. To insure better random variation degree of dual random PWM,WELL algorithm is introduced to generate random number. Simulation results show that the proposed scheme can reduce the dominant harmonic clusters of the output line voltages and the phase currents effectively, and has well-distributed spectrum in the whole frequency interval.

Key words: random PWM, switch frequency, WELL algorithm, harmonic suppression