Vibration and Loss Reduction of Permanent Magnet Synchronous Motor Driven by Synchronous PWM Control with Carrier Wave Phase Shifts

Permanent magnet synchronous motors (PMSMs) are utilized in a wide range of applications as high-power-density and highly efficient drive sources. However, a PMSM generates electromagnetic vibration and loss caused by space and time harmonics. In this paper, we propose a synchronous PWM control method for shifting the carrier wave phase against the modulation wave phase. As the proposed control matches the vibration frequencies caused by space and time harmonics, the pulsation caused by the space harmonics is canceled out by the pulsation caused by the time harmonics with the phase shift of the carrier wave. Experiments on the proposed control demonstrate that vibration in a specific frequency was reduced by 46% at 7,900 rev/min. In addition, to change the carrier phase with small current harmonics, magnet eddy-current loss was reduced by shifting the carrier wave phase. The temperature of a magnet was measured in a heat run test, and the temperature rise of the magnet could be suppressed by 5K.