Performance and applications of a small permanent magnet generator

The PM generators have the advantage of eliminating the exciter field winding, slip rings and brushes, and thus they can be very efficient and small, and in some cases cheaper than their externally excited counterparts. Many types of PM generators have been reported and each type uses different kind of PM materials and configuration to meet a specific application. This paper considers a high-speed low-power small PM generator for aerospace applications where environmental requirements are very severe. Furthermore, the main disadvantage of PM generators is the difficulty of output voltage regulation to compensate for speed and load variation, due to the lack of a simple means of field control. We present a circuit to provide a fixed dc output voltage from the generator to the load