Single-Phase On-Board Integrated Bi-Directional Charger with Power Factor Correction for an EV

Abstract

The major obstacle that prevents the widespread growth of the electric vehicles (EV's) is the shortage of the required charging infrastructure. The DC charging stations which are used for fast charging the EV battery are very costly and thus not widespread. One of the possible solutions is to place a separate on-board charger which is capable of charging the EV battery from widely available 3-phase (faster charging) and single-phase (slower charging) grid outlets. But this additional charging unit leads to increment in mass, price and volume of the EV. Since the charging and propulsion never takes place at the same time, we can utilize the traction components already present in an EV powertrain for charging. This papers deals with a single-phase integrated charger which utilizes a nine-phase traction motor and inverter already present in an EV powertrain for charging the EV battery. The bidirectional charger can also feed the power back into the grid, the concept commonly called as vehicle to grid (V2G) operation mode. No hardware rearrangement is required in the charger for the transition between charging and driving operation mode. Moreover it can operate at the grid side with unity power factor (UPF) and without the generation of any electromagnetic torque during charging/V2G mode.