2026/06/03 by Zeliang Zhang, Guangdong Bi, Yinpeng Qi +1
Engineering · #Machine Fault Diagnosis Techniques #Multilevel Inverters and Converters #Sensorless Control of Electric Motors
paper · doi:10.1109/tpel.2026.3699966
openalex publication_date 2026/06/03 · openalex created_date 2026/06/04 · openalex updated_date 2026/07/30
Open-phase faults in a dual three-phase motor with isolated 30°-shifted windings induce pronounced torque ripples. Even with fault-tolerant current controls, such as minimum-loss (ML) and maximum-torque (MT) controls, the torque ripples are still of great concern. One of the primary reasons is the voltage modulation error: even with advanced fault-tolerant current controls, conventional space-vector pulse-width modulation (SVPWM) is still applied as in the healthy case. However, under fault conditions, the inverter voltage vectors have changed, and thus the modulation scheme needs to be reconfigured. This paper therefore proposes a fault-tolerant modulation technique that accounts for the post-fault voltage vectors and optimises their dwell durations. Within the proposed modulation scheme, the post-fault phase voltages are first estimated for each switching state by considering the back electromagnetic force and mutual inductances. The corresponding post-fault voltage vectors are then synthesised based on the phase voltages and the original dwell durations from conventional SVPWM. Finally, errors between the realised post-fault voltage vectors and the reference voltage vectors are minimised via convex quadratic programming by solving for the optimal dwell durations. Experiments demonstrate up to a 50% reduction in torque-ripple amplitude and a 48.8% reduction in dispersion when integrated with MT and ML controls.