Design aspects of a 200 kW, 3600 RPM, permanent magnet generator for use in a variable speed integrated generator

In recent years, permanent magnet materials together with power electronic devices have improved both in terms of performance and commercialisation. Machine hybrids including permanent magnet materials and power electronics are already widely used. in industry and ratings are expected to increase. The design of a radial flux generator with surface mounted magnets operating at 200 kW, 3600 RPM, 720 Hz is included in this paper. The machine design described is intended for use with a rectifier on the output which feeds a DC link and inverter as part of a variable speed integrated generating set (VSIG). The main aim of the paper is to study, for a given mass of permanent magnet material, the merits of using a 120 pole arc compared with a 180 degree pole arc. Electrical parameters such as voltage waveform, inductance, voltage regulation and power output are compared. Eddy current loss in the magnet and rotor together with eddy current loss and hysteresis in the stator are examined. The calculation methods are detailed and an FEA rotating machine solver used. A machine has been built and tested and electrical measurements are compared to calculations.