A novel direct torque control for interior permanent magnet synchronous machine drive system with low ripple in torque and flux-a speed sensorless approach

A novel direct torque control (DTC) scheme for interior permanent magnet synchronous machine is proposed in this paper, which features low torque and flux ripple and almost fixed switching frequency. The torque and flux ripples have been significantly reduced if compared with those of the basic DTC reported in the literature. A speed estimation scheme is integrated with the proposed DTC scheme.