Electric vehicle battery charging algorithm using PMSM windings and an inverter as an active rectifier

A major setback for large scale electric vehicle market expansion compared to their internal combustion competitors consists in their high price and low driving range. One way of reducing the cost, dimensions and mass of electric vehicles is to eliminate the dedicated AC/DC converter used for battery charging. Alternatively, charging could be done using the motor windings as grid side inductors and controlling the inverter to operate as an active boost rectifier. The challenge in this approach is the unequal phase inductances which depend on the rotor position. Another problem appears when the battery gets discharged below the peak of the grid voltage, typically if the vehicle has not been used for a longer period of time. To avoid high currents that could damage the battery, a voltage suppression mode is introduced for safe depleted battery charging. This paper proposes and analyzes an integrated charger control algorithm to charge the battery through a permanent magnet synchronous machine (PMSM) windings.