A comparative study of high performance speed control strategies for voltage-sourced PWM inverter-fed induction motor drives

The present paper investigates the performance of different three-phase cage rotor induction motor control systems. Firstly, the field oriented methods, namely direct and indirect vector control, are investigated in both the voltage and current controlled forms. Furthermore, the possibility of field orientation aligned with the stator, airgap (main) and rotor flux vector is considered. Secondly, direct torque control methods are examined. It is found that direct torque control is less complex and gives better control characteristics than the vector control methods. Thirdly, a new control strategy based on direct torque control is considered in detail. It has been found that the performance of direct torque control can be improved further by using a more complex switching table with a mapping algorithm.