Braking torque compensation strategy and thermal behavior of a dual three-phase winding PMSM during short-circuit fault

Permanent magnet synchronous machines (PMSMs)employing the dual three-phase winding represent a suitable solution for complying with the reliability requirements typically needed in safety-critical applications. Their inherent fault-tolerant capability allows to operate the system (e.g. electro mechanical actuator or traction drive-train), even after the occurrence of a three-phase short-circuit in one winding set. Nevertheless, an appropriate post-fault control strategy is indispensable for preventing the PMSM performance derating. In this work, the design of a dual three-phase PMSM, intended for aerospace application, is presented. The PMSM performance is evaluated via finite element (FE)analysis, in both healthy and three-phase short-circuit conditions. A post-fault control strategy aimed at balancing the braking torque is then discussed. Since the implemented strategy is based on the current overload of the healthy winding, the temperature rise is experimentally investigated on the PMSM prototype. The thermal analysis verifies the compensation strategy feasibility, by proving that the thermal overload does not have a major effect on the wire insulation lifetime.