Online Drive Topology Conversion Technology for PMSM Speed Range Extension

This article proposed a smooth online drive topology conversion technology for speed range expansion of permanent magnet synchronous motor (PMSM). By converting the proposed dual-mode drive topology from torque mode to speed mode, the speed range of PMSM are doubled, which is similar to the effect of star/delta topology conversion. Based on the in-depth analysis of the motor operation stability during the conversion transient, the online topology conversion can be smoothly realized without affecting the continuous speed and torque operation of the motor. A zero-current mode-conversion method is proposed to ensure all the conversion switches operate in a zero-current state to avoid the reliability issues, such as the arcing, surge current and overvoltage in mechanical contactors. The stability and dynamic performance of the proposed dual-mode topology and the zero-current mode-conversion methods have been verified by a PMSM experimental platform.