A Control Strategy for Reducing the Torque Ripple with Optimal Stator Flux Direct Torque Controlled Induction Motor Drive

Abstract

Direct Torque Control (DTC) is an emerging technique for controlling the PWM inverter-fed induction motor drives (IMD). It allows the precise and quick control of the IM flux and torque without calling for complex control algorithms. In principle, moreover, DTC requires only the knowledge of the stator resistance. In spite of its simplicity, DTC allows a good torque control in steady state and transient operating conditions to be obtained. If number of possibilities in the vector selection process is greatly increased then this lead to a more accurate control system, which result in a reduction in the torque and flux ripples. A new switching methodology is proposed where each sector of conventional DTC is divided to two half sector (total 12 sector) and a proper vector set is defined for each provides a total 14 vectors. The performance of proposed methodology is investigated, compared, and results are validated through both by simulation and experimentation.