Smooth Pulse Number Transition Strategy Considering Time Delay in Synchronized SVPWM

In high power motor drive systems, synchronized space vector pulsewidth modulation (synchronized SVPWM) is widely used to guarantee stable control performance. Synchronized SVPWM has a characteristic that the switching frequency varies abruptly when the pulse number transitions. This article proposes a pulse number transition point at which the phase difference is minimized to remove the phase difference of the sampling point that appears during synchronized SVPWM control. In addition, for a smooth pulse number transition of synchronized SVPWM, a compensation method for the magnitude and phase error of the inverter output voltage due to the time delay and a method of removing the existing phase difference without using a phase-locked loop are proposed in consideration of the characteristic of changing switching frequency. The validity and the implementation of the proposed method are verified by experimental results using a high-power inverter driving 332 kW interior permanent magnet synchronous motor (IPMSM).