Fast Computation of the No-Load Characteristic for Wound Field Synchronous Propulsion Motors

Wound field synchronous machines (WFSMs) are gaining attention as an interesting permanent magnet (PM)-free alternative for propulsion applications. The third degree of freedom introduced by the rotor current makes the electromagnetic design of these machines not trivial. Hence, the dedicated and fast analysis tools are necessary to predict the machine behavior. This article presents a fully analytical procedure for the computation of the no-load characteristic of salient-pole WFSMs. The procedure considers the iron saturation and includes the magnetic shunt of the stator slots. The distortion of the air-gap flux density waveform introduced by the teeth saturation and the rotor saliency are considered. The procedure has been experimentally validated using a four poles, 100 kW peak power wound field synchronous motor.