A Random Pulse Position-Based Selective Noise Cancellation Modulation Method for SVPWM Driven PMSMs

Permanent magnetsynchronous motors (PMSMs) are usually driven by the SVPWM technique, which leads to annoying sideband noise near the switching frequency. Traditional random modulation techniques increase the possibility of resonance with the motor structure. This study proposes a novel random pulse position modulation-based strategy to eliminate the current harmonics and electromagnetic noise at a specific frequency. The proposed method adopts a constant switching frequency. A unique design between the pulse position and duty ratio cancels the current harmonics and acoustic noise at the selected frequency. The results show that resonance can be avoided effectively if the chosen frequency is close to the natural frequency. It is concluded that the proposed method is beneficial at lower fundamental frequencies. The techniques can substitute classic random modulation techniques with variable switching frequency in the low speed applications.