Sensorless direct power and torque control of PWM back-to-back converter-fed induction motor

A novel control scheme for PWM rectifier-inverter system is proposed. Fast control strategies such as line voltage sensorless virtual flux (VF) based direct power control with space vector modulator (DPC-SVM) for PWM rectifier and direct torque control with space vector modulator (DTC-SVM) for PWM inverter side are used. These strategies lead to good dynamic and static behaviors of the proposed control system-direct power and torque control-space vector modulated (DPT-SVM). Simulations and experiment results obtained show good performances of the proposed system. Additional power feedforward loop from a motor to PWM rectifier control side improved dynamic behaviors of the power flow control. As a result, better input-output energy matching allows decreasing the size of the DC-link capacitor.