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Mathematical Problems in Engineering
Volume 2015, Article ID 609586, 17 pages
Research Article

Direct Torque Control of Sensorless Induction Machine Drives: A Two-Stage Kalman Filter Approach

1School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640, China
2Sunwoda Electronic Corporation Limited, Shenzhen 518108, China

Received 27 May 2015; Revised 27 August 2015; Accepted 27 August 2015

Academic Editor: Mohamed Djemai

Copyright © 2015 Jinliang Zhang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Extended Kalman filter (EKF) has been widely applied for sensorless direct torque control (DTC) in induction machines (IMs). One key problem associated with EKF is that the estimator suffers from computational burden and numerical problems resulting from high order mathematical models. To reduce the computational cost, a two-stage extended Kalman filter (TEKF) based solution is presented for closed-loop stator flux, speed, and torque estimation of IM to achieve sensorless DTC-SVM operations in this paper. The novel observer can be similarly derived as the optimal two-stage Kalman filter (TKF) which has been proposed by several researchers. Compared to a straightforward implementation of a conventional EKF, the TEKF estimator can reduce the number of arithmetic operations. Simulation and experimental results verify the performance of the proposed TEKF estimator for DTC of IMs.