Wound Field Flux Switching Machine Performance Under Switched Field Excitation

This paper is concerned with investigating the performance of the wound field flux switching machine (WFFSM) under switched field excitation. In a number of instances, the field excitation is not a pure dc value. Same time for improved reliability the use of capacitors for smoother dc field excitation is undesirable. This work seeks to assess the impact on switched field excitation on the performance of the WFFSM in generator mode. An H-bridge was used to drive the wound filed coil for excitation. Two PWM based schemes were evaluated, the hysteresis current control and the classical PI current control. These were compared to the pure dc field excitation at no load. The parameters of interest are the switching frequency, torque ripple and the back emf waveform. The hysteresis current control at lower switching frequency produced a poor-quality back EMF waveform. Indicating increased torque ripple and a drop in average torque.