Fault tolerance control of phase current in permanent magnet synchronous motor control system

Abstract

As the Photoelectric tracking system develops from earth based platform to all kinds of moving platform such as plane based, ship based, car based, satellite based and missile based, the fault tolerance control system of phase current sensor is studied in order to detect and control of failure of phase current sensor on a moving platform. By using a DC-link current sensor and the switching state of the corresponding SVPWM inverter, the failure detection and fault control of three phase current sensor is achieved. Under such conditions as one failure, two failures and three failures, fault tolerance is able to be controlled. The reason why under the method, there exists error between fault tolerance control and actual phase current, is analyzed, and solution to weaken the error is provided. The experiment based on permanent magnet synchronous motor system is conducted, and the method is proven to be capable of detecting the failure of phase current sensor effectively and precisely, and controlling the fault tolerance simultaneously. With this method, even though all the three phase current sensors malfunction, the moving platform can still work by reconstructing the phase current of the motor.