Reduction of high-frequency vibration noise for dual-branch three-phase permanent magnet synchronous motors

Two-level voltage source inverters with pulse width modulation (PWM) generate multiple carrier harmonics, thereby exciting high-frequency noise from the motor. Based on a special dual-branch three-phase permanent magnet synchronous motor (PMSM), a method that utilizes a known modified space vector PWM technique is proposed. This method is able to suppress unpleasant high-frequency vibration noise as well as acoustic noise more effectively than other methods. Vibration noise near the twice carrier frequency is eliminated, and PWM vibration noise around the carrier frequency is also reduced. In particular, vibration and acoustic noise at the twice carrier frequency are eliminated using a carrier phase-shift of 0.5π and the special winding structure of the dual-branch PMSM. The effectiveness of the proposed method is confirmed using detailed experimental results.