Fault Tolerant Control Strategy Research For Sensors Of Induction Motor Control System

With the development of power electronic technology,power semiconductor technology and motor control theory,modern control technology is becoming more mature.Thanks to the advantage of low cost,simple control,and energy efficiency,induction motor control system is used widely.However,the condition to improper operation and unexpected cases also can lead the motor system to fault.Once the system occurred fault,it will prompt economic losses and even cause personal injury,if it could not be disposed in time.In addition,in some special applications,when the motor system is failure,we can't immediately stop the maintenance,and must maintain continuous operation of the system.Therefore,In order to further improve the reliability,reduce downtime and the loss brought by fault,it is of great significance to research the fault diagnosis and fault tolerant control of the induction motor system.This paper proposed some fault diagnosis and fault tolerant control strategy,in view of the current and speed sensors.Firstly,the concept of fault diagnosis and fault-tolerant control were expounded,the sensor fault types and research status at home and abroad were introduced.Then mathematical model and vector control of induction motor,the most common control method,were introduced and analyzed in detail.The above work has built the theory basis for the design of fault diagnosis and fault tolerant control strategy.Due to the induction motor is a nonlinear,strong coupling and multivariable high order system,uncertainties in the system were considered,the polynomial chaos theory is adopted to design current state observer,With the observer,real-time monitoring,fault diagnosis and fault tolerant control of current sensor are fulfilled;Then combining the observer with Lyapunov theory,speed adaptive estimator,used to realize the speed estimation,was designed.So we can realize the speed sensor fault detection,and the validity of the method is validated by computer simulation.At the same time,this method had a poor performance at the starting stage,the paper analyzed the cause.The sliding mode variable structure control and luenberger observer were used to improve the speed estimation precision.The state observer was designed to boost the performance of the rotor flux estimation,therefore the speed estimation precision was improved well,fault diagnosis and fault tolerant control of speed sensor were implemented preferably.Compared with the traditional sliding mode observer,the structure of the new observer,the way to solve the gains,and the process of solving speed estimator are more simple.Then the simulation proves the method is effective.A dSPACE real-time simulation system and main development board DS5202 ACMC were recommended particularly.Then,based on the system,fault diagnosis and fault-tolerant control strategy verification platform for sensors of induction motor was constructed.The experimental results further illustrated the feasibility of the fault-tolerant control method based on sliding mode state observer.