Current Sensor Offset and Motor Parameter Variations Estimation Method for PM Motor by Using Current Simulator

The servo system of a PM motor is required to have a fine torque response and fine speed response. The current controller of the PM motor should have a fine current response. However, when the current sensors of the U phase and V phase have offset values, the servo system of the PM motor shows a torque ripple and cannot accurately identify motor parameters such as the motor resistance Ra and motor inductance La. In order to overcome these problems, this paper proposes a new method for the fine estimation and automatic adjustment of current sensor offsets and the electrical parameters of the PM motor. The proposed method involves the use of a real-time algorithm and a current simulator, which is operated using a DSP software system. The experimental results of this study confirm that the proposed method satisfactorily estimates the offsets of the current of sensors of theU phase and V phase, Ra, and La accurately; the method also helps in the fine self-tuning of the current controller of the servo system.