Efficiency Comparison between Single Channel and Double Channel operation in Dual Three-Phase PMSM

Due to the high-power density, high torque rating, low torque ripples and fault-tolerant capability, Dual Three-Phase Permanent Magnet Synchronous Motor (DTP-PMSM) has recently emerged as a feasible alternative for automotive application. However, it comes with its own challenge of increased losses at low torque due to the use of 6-phase inverter or two three-phase inverters. This paper proposed an efficiency analysis between single channel and double channel modes in a DTP-PMSM. The system model is designed to function in two operating modes, double-channel (dual three-phase) mode with both the inverters, and single-channel (three-phase) with one of the two inverters shut down. A simulation model is prepared to calculate the efficiency, and the losses associated with different parts of battery fed DTP-PMSM drive system operated in both the modes. A mathematical detailed and nearly accurate loss model based on FEA analysis is incorporated to show the effect of different types of losses in the motor. Comparison is conducted from various aspects, such as motor efficiency, system efficiency, inverter switching and conduction losses, steady state ripples, etc. Loss distribution analysis is performed to analyze the effect and weight of different type of losses to the entire system. Efficiency comparison between single-channel and double-channel operation at different operation conditions are conducted. Efficiency map that covers torque-speed plane is generated to show a clear boundary on the efficiency performance of single and double channel operations. It clearly demonstrates that at lower torque, the efficiency of the system under single channel mode is better than the double channel mode.