Efficiency improved sensorless control scheme for electric vehicle induction motors

This study presents an energy efficient and speed-sensorless control scheme for electric vehicle induction motors (IMs). The IM drive is designed to feature characteristics such as fast dynamic response, high efficiency and low cost. Hybrid field orientation control (FOC) and direct torque control (DTC) is employed as the main control method of IM drive. This method enjoys the advantages of both FOC and DTC and eliminates certain disadvantages. A field weakening algorithm is developed and utilised within the control strategy to ensure robust operation at high speeds. The cost is lowered by eliminating the speed encoder and estimating the speed using an extended Kalman filter observer. Furthermore, a loss minimisation algorithm is associated with the main control strategy to ensure high IM drive efficiency. The effectiveness of the proposed method is verified through simulation and experimental results.