Direct Torque Control of Induction Motor Drives Using High Frequency Pulse Density Modulation for Reduced Torque Ripples and Switching Losses

A direct torque control (DTC) based on a high frequency AC (HFAC) power converter is proposed. The scheme exploits the recent advances in soft switching and pulse density modulation (PDM). The proposed HFAC-DTC scheme demonstrates the potentials of superior performance over conventional DTC schemes, at no extra system complexity or software overhead. Significant reductions in flux and torque ripples, and inrush current during startup are shown. Soft switching also results in reduction in switching losses and device stress. Simulation results from a proven model illustrate the many potentials of the new DTC scheme.