High-Frequency Harmonics and Vibration Reduction for Dual Three-Phase PMSM Using Multiple Randomized SVPWM Strategy

In order to reduce high-frequency harmonics and vibrations generated from the use of pulsewidth modulation technology, a multiple random space vector pulse width modulation (MR-SVPWM) strategy for dual three phase magnet synchronous machine is proposed. In the proposed method, the modulation period is defined as 2
N
. The carrier frequency is generated by adopting the traditional variable delayed time SVPWM method in the first
N
sampling periods. By applying average compensation for the carrier frequency in the second
N
sampling period, the current harmonics at the switching frequency can be moved to several fixed modulation frequencies. Also, the amplitude of these harmonics can be reduced. Then, the MR-SVPWM method combines 2
N
-period modulation variable delayed time SVPWM and traditional random carrier frequency PWM is designed to randomize the fixed modulation frequency. The expression for the modulation frequency of the proposed multiple randomized SVPWM is derived. It is then demonstrated that the combination of these two methods yields a synergistic effect. Due to the synergy effects of the MR-SVPWM, the higher frequency harmonics and vibration can be reduced to a low level. Experimental results are conducted to verify the effectiveness of the proposed method.