Fault-Tolerant Control of Position Sensor for Wound-Rotor Synchronous Starter/Generator

Accurate feedback of rotor position is necessary in a Wound Rotor Synchronous Starter/Generator (WRSSG) drive system, which is an great challenge to the reliability of position sensor. In case of failure of position sensor, this paper proposed a fault tolerant control (FTC) method for WRSSG based on Maximum Likelihood Voting (MLV) algorithm with two virtual sensors. When the position sensor fails, the MLV algorithm votes the most accurate position from the virtual sensors as the feedback signal of the control system. The simulation results on a WRSSG verify the feasibility of the fault-tolerant control method.

I. Introduction

Fault diagnosis and fault-tolerant control systems have been widely studied in aerospace, electric vehicle, and manufacturing, etc. Fig. 1 shows the structure of a WRSSG, which consists of three parts: the pre-exciter, the main exciter, and the main machine [1]. In a WRSSG control system, accurate rotor position is essential for WRSSG to generate a required torque. The rotor position is usually obtained by sensors such as hall sensors, encoders or resolvers. If the sensor fails, inaccurate or even incorrect rotor position will lead to motor performance degradation or even failure. Therefore, it is oblige to study fault tolerant control of sensor fault, which will increase the reliability and availability of startor/generator system.