A general-purpose inverter controls the output current using information from current sensors for high-performance motor control. However, these sensors outputs, however, have some gain and offset errors that depend on the peripheral components and the characteristics of the current sensor. These errors cause an imbalance in the output current, which causes a torque ripple. The torque ripple leads to many problems. The authors have proposed a periodic disturbance observer (PDO) as a control method for vibration suppression. The current sensor error causes a vibration with a specific frequency; thus, this paper proposes a current sensor error compensation method to apply the PDO for suppressing this specific frequency. This method can suppress the harmonic current in real time, and the current control performance can be improved by error compensation. This paper explains the proposed method and demonstrates the effectiveness of the proposed method through simulation and experimental results. In addition, this paper verifies the follow-ability of sensor error variation.
- Current sensor error
- Periodic disturbance observer
- Torque ripple suppression