SENSORLESS TORQUE CONTROL OF AN IPMSM DRIVE TAKING IRON LOSS AND SATURATION INTO ACCOUNT

El-Sawy, A. M.; Shehata, E. G.

doi:10.21608/jesaun.2012.113128

SENSORLESS TORQUE CONTROL OF AN IPMSM DRIVE TAKING IRON LOSS AND SATURATION INTO ACCOUNT

Document Type : Research Paper

Authors

A. M. El-Sawy ¹
E. G. Shehata ²

¹ Electrical Engineering Department, Faculty of Engineering, El-Minia University, EL-Minia, Egypt

² Electrical Eng. Dept., Faculty of Engineering, El -Minia University, Egypt

10.21608/jesaun.2012.113128

Abstract

This paper presents a novel direct torque control (DTC) of a sensorless interior permanent magnet synchronous motor (IPMSM). The speed and position of the IPMSM are estimated online based on active flux concept. The active flux estimation needs the quadrature axis self inductance value. The conventional two axes machine model is modified in order to include the influence of the saturation and cross saturation effect on the variation of self and cross coupling inductances in the direct and the quadrature axes. The self and cross coupling inductances values are stored in lookup table in the motor model. In addition, the iron loss is taken into the motor modeling. To overcome the large ripple content associated with the DTC, a torque/flux sliding mode controller (SMC) has been employed. The command voltage is estimated from the torque and flux errors based on the two switching functions. The space vector modulation (SVM) is combined with the SMC to ensure minimum torque and flux ripples and to provide high resolution voltage control. To overcome the stator resistance variation, a fuzzy logic estimator is designed to detect the resistance variation online. The proposed scheme has the advantages of simple implementation, and does not require an external signal injection. In addition, it combines the merits of the DTC, SMC, and SVM beside the sensorless control. Simulation works are carried out to demonstrate the ability of the proposed scheme at different operating conditions. The theoretical results are compared to published results to confirm the high performance of the proposed scheme at standstill, low and high speeds including load disturbance and parameters variation.

Keywords