Research On Full-order Observer And Fault-tolerant Control Of Dual Three-Phase Induction Motor

With the rapid development of power electronics technology,the multiphase motor drive system has gained more and more development.Compared with the traditional three-phase motor drive system,the Multiphase motor drive system has the advantages of high reliability,multiple control degrees of freedom and low dc voltage supply.In this paper,the control strategy and modulation technology,fault-tolerant control technology and full-order observer of the dual three-phase induction motor are studied.In this paper,the vector space decoupling(VSD)control strategy of dual three-phase induction motor is studied.According to the vector space decoupling(VSD)theory,the winding model of the dual three-phase induction motor is decoupled to three orthogonal harmonic subspaces,so as to realize the decoupling of the mathematical model of the dual three-phase induction motor.A SVPWM modulation algorithm based on the intermediate balance vector is designed by analyzing the voltage vector in the dual three-phase drive system.Based on the mathematical model of motor in harmonic base,the vector control system of dual three-phase induction motor based on rotor field orientation is designed.On the basis of the above,the simulation model of the dual three-phase induction motor driving system is established,and the control strategy is simulated.Then the fault-tolerant control strategy of dual three-phase induction motor is studied.The mathematical model of dual three-phase induction motor under various phase fault conditions is established,and the change of motor operation mode after phase fault is analyzed.By using asymmetric winding decoupling transformation,the decoupling control of stator moment and excitation component is realized.In the asymmetric d-q coordinate system,the flux observer and controller are designed to realize the rotor field-oriented vector control and effectively eliminate the torque ripple generated by the motor.Simulation results show the effectiveness of the fault-tolerant control strategy.The following paper aims to solve the problem that the speed measuring mechanism of the motor driving system is prone to failure.Based on the principle of full-order observer,a speed sensorless control system with parameter identification for dual three-phase induction motor is proposed.By using lyapunov theorem to construct a full-order observer,it can not only observe the rotor flux and speed during the operation of the motor,but also identify several parameters,thus improving the performance of the speed-sensorless control system.The full-order observer model is modified to realize the stable observation of the rotating speed without speed sensor when the phase is fault,andthe operation capability of the dual three-phase induction motor drive system is improved when the phase is fault.Finally,the hardware experiment platform of the dual three-phase induction motor drive system is built.the control strategy proposed in this paper is studied through the experiment.the experimental results are analyzed to demonstrate the advantages and disadvantages of the above control strategy.