A brushless exciter design for a hybrid permanent magnet generator applied to series hybrid electric vehicles

This paper discusses the design of a brushless exciter for a hybrid permanent magnet (HPM) generator for application in series hybrid electric vehicles (SHEV). The brushless exciter has a 36-pole stator winding and multi-phase rotor configuration that supplies the HPM wound field (WF) rotor via a rotating rectifier. The brushless exciter rotor components are all assembled on the same shaft as the HPM generator rotor. The HPM machine is engine mounted and has to accommodate a through shaft. This forms one of the constraints on the HPM generator and brushless exciter design. Moreover, to minimize component count the brushless exciter design is constrained to use the same laminations as those used in the HPM generator. A multiphase design approach is used for the brushless exciter rotor that, together with an uncontrolled passive rectifier, delivers a high quality DC output to the HPM WF. This eliminates the necessity for passive smoothing of the rectified DC output and hence improves the reliability of the system. Dynamic behaviour of the brushless exciter is analysed to examine the response and effectiveness of the proposed design.