Fault-Tolerant Control for DTP-PMSM With Arbitrary Open Phase Fault Based on Multi-Synchronous Rotating Coordinate System and Voltage Compensation

Dual Three-Phase Permanent Magnet Synchronous Motors (DTP-PMSM) have been extensively employed in diverse scenarios demanding high reliability, owing to their superior operational performance. However, traditional Fault-Tolerant Control (FTC) strategies have limitations such as complex controller structures, increased motor copper losses, and intensified torque pulsation, which restrict their application potential. ​ The voltage error caused by inconsistent voltage transmission under open phase faults (OPFs) in arbitrary phase between the controller and the motor terminal is considered. Theoretical analysis shows that this error will introduce 2nd-order negative sequence current in the d-q synchronous rotating coordinate system, leading to 2nd-order torque ripple. An FTC strategy that integrates multiple synchronous rotating coordinate systems and voltage compensation mechanisms is proposed to enhance the system's robustness against OPF in an arbitrary phase and suppress torque ripple. In this paper, based on the vector space decoupling model, the voltage compensation expressions under general OPFs scenarios are derived. On this basis, a multi-rotating frame control scheme for the 2nd-order negative-sequence currents is further designed, suppressing the residual torque ripple. Considering that low-pass filters are prone to introducing phase delay, the notch filter is introduced in the coordinate transformation process to eliminate this negative impact. Finally, experimental verification shows that the proposed strategy improves the torque output smoothness under OPFs in an arbitrary phase.