Predictive torque control of induction motor drive with simplified weighting factor selection

Abstract

PTC is a kind of finite control set model predictive control (FCS-MPC) technique gaining its attention in high-performance electric drive applications due to its intuitive concepts and simple structure. Further, additional control parameters (switching frequency, common mode voltage etc.) can be directly included into the objective-function of the control algorithm. However, suitable weighting factors are required to maintain the relative balance between diverse control parameters used in the objective-function. Stator flux and torque are used as control parameters in the implementation of conventional PTC and the empirical process is used to obtain the suitable weighting factor in the objective-function. To avoid this problem, simple additive weighting (SAW) method is introduced in the objective-function of PTC and this method simplifies the selection of weighting factors in the objective-function. To reduce the average switching frequency and computational burden present in the conventional PTC used for a 2-level VSI fed induction motor drive; four appropriate switching states are used to obtain the optimal control action instead of eight switching states of 2 - level VSI. Simulation results are presented for the proposed control algorithm and these results confirm the effectiveness of proposed control algorithm compared conventional PTC with reduced switching frequency.