Improved Signal-Injection Sensorless Control Robust to Inverter Nonlinearity Effects by Prediction of Voltage Disturbance

In signal-injection sensorless control, the estimated rotor position includes considerable error induced by the inverter nonlinearity effects. It would degrade overall performances of the sensorless drive, and it could even result in the failure of the position tracking. In this paper, an improved signal-injection sensorless control thanks to the compensation of the voltage error is proposed. The compensation depends on a precise calculation method of the voltage error induced by the inverter nonlinearity. The proposed method effectively reduces the voltage disturbance especially under the switching frequency injection for sensorless control. The performance of the proposed method is verified by computer simulations and experimental results.