An IPMSM position control system using high frequency injection sensorless technique

This paper proposes a high performance sensorless interior permanent magnet synchronous motor control system using a high frequency injection technique. A new estimation method which uses both the high-frequency d-axis current and q-axis current to estimate the rotor position is investigated. By using the proposed method, the hypothesis-synchronization signal used in the conventional high frequency injection method can be eliminated. A 1.25 kHz, 15V, sinusoidal waveform voltage is injected into the d-axis synchronous frame of the motor, and then the high frequency d-axis and q-axis currents can be measured to determine the rotor position of the motor. By using this new method, the estimation rotor position error is within ±2 electrical degrees. A sensorless position control system is implemented by using the high frequency injecting technique. The system can achieve precise position control with satisfactory performance.