Single-Phase Integrated Onboard Battery Charger Incorporating Symmetrical Six-Phase Induction Motor

Abstract

In this article, a novel single-phase integrated bidirectional onboard charger based on a symmetrical six-phase induction motor is proposed. The charger has grid-to-vehicle, vehicle-to-grid, and vehicle-to-vehicle charging capabilities. In the proposed charger, the machine windings are employed as inductors, and the six-leg converter accomplishes ac–dc and dc–dc conversions. The windings of a six-phase machine form two sets of three-phase windings. One set of three-phase windings is used as grid filter inductance in single-phase ac–dc conversion. The remaining set serves as filter inductances for the dc–dc converter, which is a bidirectional, noninverting buck-boost converter. Compared to existing single-phase ac chargers, the proposed charger circuit can be easily reconfigured to accept both ac and dc sources. Reconfiguration from vehicle driving to battery charging mode does not require any extra fast switching elements or passive components. An efficient control technique is used to avoid redundant switching losses in a dc–dc converter. A scaled-down laboratory prototype is built and tested to verify the proposed hypothesis.