Fault-Tolerant Control for Open Winding PMSM System with Common DC Bus Based on 120° Decoupled Modulation Strategy

To improve the fault-tolerant performance of the driving system for open winding PMSM (OW-PMSM) with common DC bus, a new fault-tolerant control (FTC) method for single leg open-circuit fault is proposed in this paper. Firstly, the single leg open-circuit fault is introduced. Then, post-fault topology is reconfigured, followed by the analysis of the FTC strategy based on SPWM. By using the specific modulation method, a novel FTC (NFTC) strategy is proposed. To improve the output voltage, the NFTC strategy based on SVPWM is proposed also. The same modulation strategy can be used for both the healthy and the fault-tolerant operation mode by using the NFTC. Meanwhile, the OW-PMSM system can operate in the fault-tolerant operation mode without reducing the output capacity. The effectiveness of the proposed method is verified by simulation results.