A torque ripple reduction method by current sensor offset error compensation

Abstract

This paper presents a reduction method for a torque ripple resulting from a motor phase current sensor offset error for motor drive applications such as a hybrid electric vehicle (HEV). The proposed method compensates for the detected motor phase current offset error by subtracting the detected motor phase current offset error value indirectly estimated using the inverter offset voltage reference value from the detected motor phase current value after the offset component of the inverter output voltage reference is calculated by a discrete Fourier transform and a digital low pass filter. The main feature of the proposed method is its ability to compensate for the detected motor phase current offset error that varies during inverter-motor drive. In this paper, the effectiveness of the proposed method with the motor torque analysis is discussed in detail. In the condition of the torque reference from 10[Nm] to 100[Nm] and the motor rotation speed of 1000[rpm], the average value of the torque ripple with the proposed method is 10[Nm] and is reduced by one-second (1/2) compared with the average value of the torque ripple without the proposed method.