Rotor Eddy Current Power Loss in Permanent Magnet Synchronous Generators Feeding Uncontrolled Rectifier Loads

Analytical methods and transient finite element analysis (FEA) with rotating mesh are used to calculate rotor eddy current power loss in a permanent magnet synchronous generator connected to an uncontrolled bridge rectifier. Two winding and rectifier topologies are considered: a three-phase winding with a three-phase bridge rectifier and a double three-phase winding with a three-phase rectifier each, connected in series. Both magnet flux tooth ripple and stator magneto-motive force harmonics are considered in the calculation of rotor loss; the harmonics are added vectorially. Good agreement is observed between analytical and FEA for constant dc link current and constant voltage loads. The machine with double three-phase windings was found to have considerably lower rotor losses than the machine with one single three-phase winding.