A controlled PWM AC/DC converter for a high-speed brushless generator for minimum kVA rating

This paper proposes a control technique for an ac/dc converter and high-speed single-phase brushless ac generator topology with a reactive armature winding. An ac-to-dc pulsewidth-modulation (PWM) converter is used with phase angle control to deliver a controlled power factor for a wide speed range while maintaining a low kVA rating of the converter and the generator. The generator is a flux-switching machine, derived from a combination of the inductor alternator and the switched reluctance machine. The electrical characteristics of the generator are determined from open-circuit, short-circuit, and load tests performed on an experimental generator. A Simulink model is developed for the ac-to-dc PWM converter and the simulated voltage and current waveforms show that the kVA rating of the converter and the generator can be minimized through control of the power factor of the generator. This novel generator is shown to be simple to control and can be used for micro turbine applications and efficient low-cost independent power generation. The converter also allows the machine to be used as an integrated starter alternator.