SENSORLESS VECTOR CONTROL OF INDUCTION MOTORUSING MODEL REFERENCE ADAPTIVE SYSTEM

The implementation and performance evaluation of sensorless vector control of three-phase induction motor is carried out in this paper which uses Model Reference Adaptive System (MRAS) technique for the estimation of motor speed. Sensorless control is basically a control technique in which speed estimation of motor is done without using speed sensor. Sensorless control increases the robustness, ruggedness of the system and reduces the cost, complexity, electromagnetic interference and maintenance required for the drive. MRAS technique is a widely used technique for speed estimation because of its simple implementation. In order to provide switching control signals to the legs of the IGBT's based two-level inverter; Space Vector Pulse Width Modulation (SVPWM) technique is used in this paper. This technique is based on the rotating space vectors. SVPWM provides better utilization of DC bus voltage and also the harmonic content and the switching losses gets reduced in this technique. The performance of MRAS technique used for speed estimation is evaluated for various values of load torque and speed. The simulation results show the feasibility and robustness of this method for high performance application.