Integrated onboard single‐stage battery charger for PEVs incorporating asymmetrical six‐phase induction machine

Abstract

This study proposes an integrated battery charger for plug-in electric vehicles (PEVs) that involves an asymmetrical six-phase induction motor as propulsion drive. Proposed power electronic interface (PEI) uses a CuK-based bidirectional DC/DC converter, which is capable of performing buck/boost function during all modes of operation. It operates as a power factor correction converter during plug-in charging mode, and a single switch inverting buck/boost converter in propulsion and regenerative braking modes. Selection of a wide range of battery voltages and adequate control over regenerative braking can be achieved with the proposed multi-functional converter. In addition, size, weight and cost of the charger are also reduced, as it involves a minimum number of components compared to existing buck/boost converters used in chargers. By utilising a six-phase induction machine drive in the propulsion system, efficiency and power density of the PEI is improved. This drive even allows for further modifications to the proposed topology. An efficient indirect field-oriented control for the six-phase machine is also demonstrated in the study. The proposed PEI is highly suitable for onboard charger and propulsion system of PEVs. A laboratory prototype of the aforementioned converter and propulsion drive has been built to validate all modes of vehicle operation.