H infinity Observer Based Sensor-less Control Strategy for Interior Permanent Magnet Synchronous Motor

Nowadays a sensor-less vector control system for a motor drive becomes promising to avoid a position sensor. A back electro-motive-force or flux observer is used for sensor-less drive of permanent magnet synchronous motors from middle to high speed range. Thus, the estimation accuracy of the observer influences sensor-less drive performance. This paper proposes a sensorless vector control system using the H infinity flux observer in which the observer gain is designed based on the H infinity control theory. This observer is insensitive to high frequency disturbances such as voltage disturbance due to non-linearity of PWM voltage source inverter, measurement noise of current sensors, and modeling errors. So, the total performance of a sensor-less control system is enhanced. The detailed configuration of the H infinity flux observer is described in this paper. Simulation results are compared with the conventional full-order flux observer-based sensor-less system.