Sensorless Direct Thrust Control of a Linear Induction Motor Based on MRAS

Abstract

Direct thrust control based on space-vector modulation (DTC-SVM) can achieve constant switching frequency and reduce thrust and flux ripples compared to conventional DTC. This paper presents DTC-SVM to improve the performance of linear induction motor (LIM). More enhancements can be achieved by using a sensorless method of the linear speed for LIM. The estimation method is based on model reference adaptive system (MRAS). Proportional Integral (PI) controller is used to control the speed of LIM. The output of the PI controller is considered as the reference thrust for DTC-SVM. The overall system performance and effectiveness of the proposed method are evaluated via comprehensive simulations results where lower ripples associated with both thrust and flux linkages waveforms and better speed tracking.