Current measurement issues in sensorless control algorithm using high frequency signal injection method

This paper presents the current measurement issues in sensorless control of a permanent magnet (PM) machine based on the fluctuating high frequency voltage signal injection (HFI) method. In such a sensorless control of the PM machine, the accuracy of the rotor position estimation mainly depends on the accuracy of the current measurement of the drive system. The accuracy of current measurement mainly depends on the current scaling errors, offset currents, and the quantization errors of the analog-to-digital (A/D) converter. In this paper, the effects of the current measurement errors on the accuracy of the rotor position estimation in sensorless control of the PM machine based on the HFI method is analyzed using an example of current measurement system and sensorless control scheme. The simulation and experimental results are shown in order to verify the validity of the analysis results.