Dynamic Analysis of Torque Ripple of Direct-Drive Disc Permanent Magnet Synchronous Motor on Low-Floor Independent Wheel-Set Bogie Track Trains

This study proposes a low-floor independent wheel-set bogie layout for urban track trains powered by direct-drive disc permanent magnet synchronous motors (PMSMs). Torque ripple occurs in the output torque of the disc PMSM since the pole arc coefficient, the skew pole angle of permanent magnets (PMs) and other machine parameters have an impact on the cogging torque, which exerts stress on the low-floor independent wheel-set bogie track train system. To calculate the impact of the torque ripple of disc PMSMs on the dynamic performance of low-floor independent wheel bogie track trains, the motor torque ripple is first analyzed and optimized by using Maxwell. Then, a low-floor independent wheel-set bogie track train model is established by using the multi-body dynamics simulation software SIMPACK, and the dynamic impact of torque ripple of disc PMSMs on the train are simulated and analyzed. Calculation results reveal that when urban track trains run through a curve track at an increasing speed, the torque ripple of the disc PMSM considerably increases the wear work of the dynamic index. And it also has a significant impact on the nonlinear critical speed and longitudinal acceleration of the track train when passing through a straight track. This work has a certain reference value for the investigation of torque ripple of direct-drive disc PMSMs, particularly for the dynamic analysis of low-floor independent wheel-set bogie track trains.