Fault diagnosis and fault-tolerant control of a dc-link voltage sensor for PV inverters

This paper proposes a method for fault diagnosis and fault-tolerant control of a dc-link voltage sensor for two-stage three-phase grid-connected PV inverters. In this system, a sensor is essential for power conversion. A sensor fault is detected when there is an error between the sensed and estimated values, which are obtained from a dc-link voltage sensorless algorithm. Fault-tolerant control is achieved by using the estimated values. A deadbeat current controller is used to meet the dynamic characteristic of the proposed algorithm. The proposed algorithm is validated by simulation and experimental results.