三相交流電流センサのゲイン異常検出手法

抄録

This paper proposes a novel method for detecting the gain fault of 3-phase AC current sensors in power electronics systems. In conventional methods, the sensor gain fault is detected by comparing the RMS values of the detection current of each phase. However, for an unbalanced three-phase load, a higher current will flow in the phase with the lower impedance, which causes misdiagnoses. In contrast, the proposed method utilizes the product of the detection current in each phase and sum of the detection current as part of the abnormality calculation (gain error calculation) of each current sensor, which can reduce calculation errors caused by an imbalance in the three-phase load. Simulation results show that the method can calculate the abnormality of the sensors with small error even if there is an imbalance in the three-phase load. Moreover, simulation results under conditions of varying current amplitude and frequency indicates that the method can detect sensor faults under transient conditions.