Severity Monitoring and Torque Ripple Suppression Based on x-Subspace Current Residuals for Symmetrical Six-phase PMSMs with Interturn Faults

An integrated method is proposed for monitoring the severity of interturn short-circuit faults (ISCF) and suppressing torque ripple in symmetrical six-phase permanent magnet synchronous motors (PMSM) based solely on the x-subspace current residuals. Compared to conventional ISCF severity monitoring and torque ripple suppression methods, the proposed approach utilizes only the residual x-current signal, thereby reducing the number of input signals. Compared to conventional methods based on d-q current residuals, the proposed method is largely unaffected by permanent magnet flux linkage. Compared to conventional methods for suppressing torque ripple based on zero-sequence voltage, the proposed method requires no additional hardware. The proposed method does not require specific values for short-circuit current and short-circuit turn ratio, enabling fault diagnosis and torque ripple suppression for ISCF. Experimental results demonstrate the effectiveness of the proposed method.