Current Sensor Fault Diagnosis And Tolerant Control Of Inverter

Induction motor drives are extensively used in the industry due to mechanical ruggedness and reduced cost.Because the reliability of the control system is related to the efficiency of production and property safety,reliability has gradually become a hot issue in recent years.Sensor as a precision part of the control system,its reliability is of great significance.Firstly,a fault diagnosis system based on coordinate transformation is proposed for fault diagnosis of current sensor in speed-sensorless control.It can be used to determine whether the single-phase fault or double-phase fault by the property of Clark transformation.The ? phase of Clark transformation is usually located in the a-phase,but it can also be positioned on the b-phase by counterclockwise rotation of 120°.Different positioning methods can locate faults of different phase sensors.The current sensor fault is judged by the difference between the value of inverse Park transformation and the value of Clark transformation.This diagnostic method is computationally small and accurate in diagnosis.Secondly,for the fault tolerant control of the current sensor in the speed-sensorless control,a full-order observer with no stator current as the state variable is proposed.The full-order observer with the rotor flux and the stator flux as the state variable can reduce the adverse effects,and it is more conducive to fault tolerance control of current sensor faults.We construct the Lyapunov equation reasonably and derive the adaptive law of speed according to Lyapunov’s stability theorem.The Eulerian discretization and trapezoidal discretization of the whole order observer are given.The Eulerian discretization and trapezoidal discretization of the whole order observer are given.To add predictions in the trapezoidal method can reduce the calculation of trapezoidal method,which is applicated to high-speed control system.A new missing current compensation method is proposed to take place of the value of faulty current sensor by the mix of estimated value through the full order observer and the compensation one.The maximum value compensation method is used to solve the problem of data overflow and speed transformation in the current compensation method of steady state adaptive rate.On this basis,a single current sensor vector control scheme without speed sensor is proposed.Finally,based on ARM2.2Kw platform,a series of tests verify the proposed current sensor fault diagnosis and fault-tolerant control scheme.The experimental results show that the fault diagnosis strategy is accurate.In thi s paper,the single current sensor vector control scheme without speed sensor is stable in the full speed range.What’s more,the current sinusoidality is very good and the speed is smooth.it fills the lack of domestic and foreign in this direction...