High-Frequency Harmonics and Vibration Reduction for Dual Three-Phase PMSM Using Multiple Randomized SVPWM Strategy
Wenxiang Zhao, Jichao Feng, Tao Tao, Chen Wang, S. Liu
Abstract
In order to reduce high-frequency harmonics and vibrations generated from the use of pulse width modulation technology, a multiple random SVPWM (MR-SVPWM) strategy for dual three phase PMSM is proposed. In the proposed method, the modulation period is defined as 2 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> . The carrier frequency is generated by adopting the traditional variable delayed time (VDT) SVPWM method in the first <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> sampling periods. By applying average compensation for the carrier frequency in the second <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> 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 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> -period modulation variable delayed time (2 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> -PMVDT) SVPWM and traditional random carrier frequency PWM (RCF-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.