This paper proposes an overmodulation method for a five-leg inverter (FLI) driving a dual-motor. The FLI is adopted to reduce cost, volume, and weight in dual-motor drive systems. However, the FLI inherently exhibits conflicting switching state demands on the common leg, which may constrain dc bus utilization and limit the operable speed range. To improve the voltage utilization and extend the operable speed range of the motors fed by FLI, it is necessary to adopt an overmodulation method. Therefore, this paper proposes an overmodulation method that considers the switching states of the common leg and the voltage constraints imposed on each leg. In addition, the proposed method can implement the overmodulation in three legs connected to a desired motor, where the speed should be increased. Simulation results verify the validity of the proposed method using the PSIM simulation.
