A series regulated open-winding PM generator based constant voltage, variable frequency AC distribution system

Permanent magnet synchronous generators have been shown to be lower cost, lighter in weight and more efficient when compared to a wound-field synchronous generator with a brushless exciter. However, due to the fact that the field from the magnets cannot be adjusted, PM machines have seen less application when operated in the generation mode. In this paper, it is proposed to regulate the load side voltage of an open-winding permanent magnet synchronous generator by injecting reactive power in a series fashion as the rotor speed and load level vary. The var source is a voltage source inverter that is directly connected in series to the generator. The operating principle will be explained. A detailed comparison between the proposed topology and existing shunt regulated system will be presented. In addition, the dimensioning of the compensation inverter will be discussed. The control method of the proposed system will be proposed and validated by simulation and experimental study.