Sensorless direct torque control of induction motors used in electric vehicle

J. Faiz, M.B.B. Sharifian, A. Keyhani, A.B. Proca
Dept. of Electr. & Comput. Eng., Univ. of Tehran, Iran

This paper appears in: IEEE Transactions on Energy Conversion
Publication Date: March 2003
On page(s): 1-10
Volume: 18, Issue: 1
ISSN: 0885-8969
Inspec Accession Number: 7551654

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Abstract:
A three-phase squirrel-cage induction motor is used as a propulsion system of an electric vehicle (EV). The motor is controlled at different operating conditions using a direct torque control (DTC) technique combined with a new switching pattern producing low harmonics. The operating flux of the motor is chosen optimally for losses minimization and good dynamic response. Since speed estimation is sensitive to rotor resistance variations, the rotor resistance value is calculated and modified in real time continuously. Simulation and experimental results show that the proposed DTC is able to follow the reference speed (which may be only input reference of the system) with a reasonable dynamic and relatively low error.