Space Vector Based Hybrid PWM Algorithm for Direct Torque Controlled Induction Motor Drives for Reduced Common Mode Voltage

Abstract

Direct torque control (DTC) is gaining importance in the industry due to its simplicity and dynamic performance. In spite of its simplicity it generates high level common mode voltage (CMV) variations and steady state ripples. This paper presents a simplified space vector based hybrid pulse width modulation (HPWM) technique for the reduction of CMV and steady state ripple in direct torque controlled induction motor drives. In the proposed approach different active zero state PWM (AZPWM) sequences are considered in which two active voltage vectors are utilized with two active and opposite voltage vectors for composition of reference voltage vector and a procedure is presented for designing a new HPWM technique involving four AZPWM sequences for reduced current ripple. To validate the proposed PWM algorithm, numerical simulation studies have been carried out using MATLAB-Simulink and results are presented and compared