Dual Three-Phase-Winding Permanent-Magnet Synchronous Motors: An Investigation of the Optimal Carrier Phase-Shift Angle

In this article, we investigate the optimal carrier phase-shift angle to reduce harmonic iron loss under various operating conditions, such as torque, speed, dc voltage, and carrier frequency, on a dual three-phase-winding permanent-magnet synchronous motor (PMSM). We calculate the carrier harmonic voltage by theoretical analysis and relate it to the modulation index in the torque–speed property. The carrier harmonic impedance behaviors are revealed in terms of the linkage magnetic flux of the first and second windings with the carrier phase-shift angle. By using the calculated carrier harmonic voltage and impedance, we reveal and verify the optimal carrier phase-shift angle of a phase-shift pulsewidth modulation (PWM) to reduce the harmonic iron loss on a dual three-phase motor by measured results under variable torque–speed properties.