Combining the principles of sliding mode, direct torque control, and space-vector modulation in a high-performance sensorless AC drive

A sensorless induction motor drive is presented, in which the principles of sliding-mode control, direct torque control (DTC), and space-vector modulation are combined to ensure high-performance operation, both in the steady state and under transient conditions. Merits of the classic DTC transient behavior are preserved, while the steady-state operation is significantly improved. The torque and flux controllers, and motor state observer are of the sliding-mode type. The inverter is directly controlled on the basis of torque and flux errors, using space-vector pulsewidth modulation. Computer simulations and experimental results presented demonstrate the robustness, accuracy, quickness, and low-chattering, wide-speed-range operation of the drive.