Fault-Tolerant Control of Position Signals for Switched Reluctance Motor Drives

Accurate and continuous rotor position information is essential for switched reluctance motor (SRM) drives operating in variable speed drive applications. To increase the SRM drives reliability regarding position sensor failures, an active position sensor fault-tolerant controller is presented in this paper. The proposed approach uses two sensorless methods and a position sensor with a maximum-likelihood voting algorithm. The rotor position is estimated from the sensorless method in case of position sensor fault, by an improved pulse injection method in the current-chopping-control mode in a low-speed operation and a current-gradient method in the single-pulse-control mode in a high-speed operation. Through the analysis of the fault position signals of SRM, a new fault diagnosis method of position signals based on the predictions of the edges is adopted in this paper. Experimental results on a three-phase 12/8 SRM demonstrate the effectiveness of both the fault diagnosis algorithm and the fault-tolerant control scheme.