Fault diagnosis for multiple current sensors in grid-connected inverter based on average modulation voltage

Grid-connected inverters are the core equipment in the renewable power system. There are multiple current sensors which may affect the driving module of the switch in inverter. In multiple current sensor fault diagnosis, the coupling between fault components makes fault diagnosis difficult. This paper presents an offset fault diagnosis method of multiple current sensors based on the average modulation voltage model. Based on the influence of current sensor offset fault in the system, the average modulation voltage model is established in three-phase stationary coordinates. The difference between the measured value of the current and the actual value is estimated through the model when the offset fault occurs. And then the fault is located. Experimental results show that the fault can be located accurately and fault tolerant control can be performed by this method when there are offset faults in multiple sensors simultaneously. Based on the influence of current sensor offset fault in the system, the average modulation voltage value model is established in three-phase stationary coordinates.The difference between the measured value of the current and the actual value is estimated through the model when the offset fault occurs. Experimental results show that this method can accurately locate the fault and perform fault tolerant control when there are offset faults in multiple sensors simultaneously.image