Research of harmonics and circulating current suppression in paralleled inverters fed permanent magnet synchronous motor drive system

This paper studies and proposes a harmonic-optimized control strategy for the paralleled voltage source inverters (VSI) fed permanent magnet synchronous motor (PMSM) drive. The system configuration and equivalent model of the paralleled VSIs fed PMSM drive are developed and analyzed. The mathematical analysis reveals the principle and performance of the carrier phase-shifted space vector pulse width modulation (CPS-SVPWM) technique. Based on that, the CPS-SVPWM and interleaved current operation are proposed to suppress the harmonics in the motor current. An additional control loop is also designed to suppress the possible circulating current by tuning the dwelling time of zero vectors dynamically. Simulation and experimental results have been given to validate the effectiveness of the proposed control strategies.