A compensation method for a motor phase current sensor offset error using a voltage-source-inverter output voltage reference value

This paper presents a method for reducing a motor torque ripple resulting from a motor phase current sensor offset error for motor drive applications such as a hybrid electric vehicle. The proposed method estimates the motor phase current sensor offset error on the basis of the direct voltage value included in the voltage source inverter output voltage reference value calculated by a discrete Fourier transform. It then compensates for the motor phase current sensor offset error by subtracting the estimated motor phase current sensor offset error value from the detected motor phase current value. Its main feature is its ability to compensate for the motor phase current sensor offset error that varies due to temperature change while a voltage source inverter and a motor are driven. The effectiveness of the proposed method for reducing the motor torque ripple with reference to simulation results is discussed in detail. These simulation results reveal that the proposed method can compensate for the motor phase current sensor offset error with less than or equal to +-1[A] difference and reduce the average value of the motor torque ripple to half (1/2) of that without the proposed method in steady state in which the motor torque reference is from 10[Nm] to 80[Nm] and the motor rotation speed is 1000[rpm]. Also, in the transient conditions in which the motor rotation speed and the motor torque reference vary, the motor phase current sensor offset error can be compensated for normally, and the stable motor torque without a motor torque ripple of a fundamental frequency component can be obtained.