Review of Control Techniques for Dual Three-Phase PMSM Drives with Low Carrier Ratios

The dual three-phase PMSM (DTP-PMSM) drives have received wide attention at high-power high-efficiency applications due to their merits of high output current ability and copper-loss-free field excitation. Meanwhile, the DTP-PMSM drive provides higher fault-tolerant capability for high-reliability applications, e.g., pumps and actuators in aircraft. For high-power drives with limited switching frequencies and high-speed drives with large fundamental frequencies, the ratio of switching frequency to fundamental frequency, i.e., the carrier ratio, is usually below 15, which would significantly degrade the control performance. The purpose of this paper is to review the recent work on the modulation and control schemes for improving the operation performance of DTP-PMSM drives with low carrier ratios. Specifically, three categories of methods, i.e., the space vector modulation based control, the model predictive control (MPC), and the optimized pulse pattern (OPP) based control are reviewed with principles and performance. In addition, brief discussions regarding the comparison and future trends are presented for low-carrier-ratio (LCR) modulation and control schemes of DTP-PMSM drives.