DISCRETE SPACE VECTOR MODULATION ALGORITHM BASED VECTOR CONTROLLED INDUCTION MOTOR DRIVE

Abstract

This paper presents a discrete space vector modulation (DSVM) algorithm based vector controlled induction motor drive for reduced torque and current ripples in steady state. The classical vector control algorithm gives good transient and steady state response. But, the complexity involved in the classical vector control is more due to the reference frame transformations. To reduce the complexity, later direct torque control has been developed. But, it gives large steady state ripple. Hence, to overcome the drawbacks of vector and direct torque control algorithms, a simple and novel vector control algorithm is proposed in this paper. The proposed algorithm combines the principles of both control algorithms. The reference currents are calculated based on the vector control. Then, the current error signals will be generated by comparing the actual and reference currents. By using the current error signals, sector information and lookup table, a suitable voltage vector is selected in order to keep the current errors within the hysteresis bands as per the principle of direct torque control. In the proposed algorithm, a 5-level hysteresis controller is used for q-axis current and 2-level hysteresis controller is used for d-axis current. To validate the proposed lookup tables based vector control algorithm, numerical simulation studies have been carried out and compared. The results show the effectiveness of the proposed algorithm.