Current sensor-less speed servo system of PM motor based on self-tuning current simulator

This paper proposes a new speed servo system of permanent magnet AC servo motor without current sensor, which is constructed by the proposed self-tuning current simulator of PM motor. The proposed current sensor-less speed servo system is simple and economical. The sensor of the proposed system is only a position sensor. The current simulator is under the influence of both the voltage limitation and the dead-time of PWM inverter. In order to overcome this problem, we propose the compensation algorithm of the voltage limitation and the dead-time for the current simulator. Moreover, in the current sensor-less speed servo system, it is important to identify the electrical parameters of PM motor accurately. This paper proposes a new identification method of the electrical parameters without the information of motor current. The experimental results point out that the proposed self-tuning current simulator based speed servo system has the desired current and speed response.