Fault-tolerant control for current sensors of doubly fed induction generators based on an improved fault detection method

Abstract

Fault-tolerant control of current sensors is studied in this paper to improve the reliability of a doubly fed induction generator (DFIG). A fault-tolerant control system of current sensors is presented for the DFIG, which consists of a new current observer and an improved current sensor fault detection algorithm. The current observer is constructed by using only voltage signals as inputs. The fault detection algorithm is based on the current observer, in which an adaptive threshold and different fault duration times are considered. The performance of the proposed observer, improved fault detection algorithm, and fault-tolerant control system are investigated by simulation. The results indicate that the outputs of the observer and the sensor are highly coherent. The fault detection algorithm can efficiently detect both soft and hard faults in current sensors, and the fault-tolerant control system can effectively tolerate both types of faults.