Influence of PM wedges in Wound-Rotor Synchronous Starter/Generator

In the starting mode, the exciter hardly provides enough field current for Main Generator to start the aircraft engine, owing to the low speed. In this paper PM wedges are used in the Wound-Rotor Synchronous Starter/Generator to improve the excitation field. By magnetized at tangential direction, installed adjacent salient wound-rotor poles, these PM-wedges combine parallel flux path with rotor fielding windings. It can increase the electromagnetic torque in starter mode and improve the out-put voltage in the generator mode. What's more, this method can de-excite entirely in the short-circuit fault and keep the higher safety than other structures.