Current control in overmodulation range for space vector modulation based vector controlled induction motor drives

Overmodulation enhances the power utilization of the installed capacity of a voltage source inverter. A space vector strategy is used for constant switching frequency inverters. In order to achieve the overmodulation a modified reference signal with nonuniform angular velocity is generated using a preprocessor. Such a reference wave produces low frequency harmonics in currents. The presence of current harmonics restricts the bandwidth of the fundamental component current controller in the overmodulation range. On the other hand a high bandwidth current controller is mandatory for vector control. A compensating current control is presented to allow for high bandwidth current control in synchronous coordinates.