Compensation of Current Measurement Error for Current-Controlled PMSM Drives

Accurate measurement of phase current is crucial in a current-controlled permanent-magnet synchronous machine (PMSM) drive system. Current measurement error directly deteriorates torque control performance. This paper analyzes effects of the current measurement error on the phase current and the output voltage of the current controller. Based on the analysis, a compensation method is proposed. The proposed method compensates the offset and scaling errors separately without any additional hardware but using the commanded voltage reference of the current controller. The proposed method can be applied to general current-controlled PMSM drives in the whole operation range. Experimental results verify the effectiveness of the proposed compensation method.