Novel integrated charger concepts using six phase electrical machines as boost-buck converter

Novel single-phase integrated charger concepts based on six-phase electrical machines are presented in this paper. Well known reconnections for three-phase machines are reviewed and proposed as a basis for the series connected boost-buck converters, in which each stage is represented by one of the two three-phase machine windings and power electronic converters. The aim of these boost-buck converters is to provide rectification of the AC currents at unity power factor in addition to adjusting the voltage to lower levels to accommodate deeply discharged batteries. Furthermore, shaft torque as well as the need for a separate DC/DC converter or expensive switches for reconnection of machine windings are avoided. Two new concepts are presented and compared in terms of losses and extra components. Efficiency levels up to 93% are measured in a laboratory prototype.