Iron Losses of Dual-Star PMSMs with Open-Circuit Fault under Fault-Tolerant Control

In this paper the iron losses of dual-star permanent-magnet synchronous machines under fault-tolerant control with phase open-circuit fault are investigated. Various faults including one or two open-circuits in different phases are considered. The iron loss terms, namely hysteresis, eddy-current, anomalous, and rotational losses, considering harmonics are calculated based on a priori knowledge of magnetic field distribution obtained by magnetostatic FE simulations. A variety of motor topologies including laminated-core surface-mounted or interior permanent magnet with distributed or concentrated winding are studied. As far as the core losses are concerned, it is observed that the machines are ill-conditioned under the post-fault control, i.e. the iron losses considerably increase, particularly at high speeds. Moreover, in contrast to the healthy case, the iron losses will not be distributed evenly among the stator teeth which leads to concentration of loss in some segments of the core.