Induction Motor Direct Torque Control with Synchronous PWM

A novel induction motor direct torque control (DTC) algorithm with synchronous modulation is presented. Compared to the traditional DTC method, whose main drawback presence of low-frequency harmonics (sub-harmonics), in proposed PWM switching frequency imposed be an integer multiple supply frequency. This achieved by continuously adjusting period significantly reduce harmonics. The devised has been tested on inverter-fed drive system, and obtained results show important reduction sub-harmonic spectral content developed respect a conventional while maintaining at same time high dynamic response.