Research On Fault-Tolerant Control Of Open-End Winding Induction Motor Based On Dual Three-Level Inverter

Taking open-end winding induction motor as the control object,the topology of dual three-level inverter with a single DC is selected,the system during normal operation and fault state is studied separately.Firstly,based on the mathematical model of the induction motor and the topology of the inverter,the open-end winding motor is modeled,and on this basis,the decoupling control strategy of double-end power supply is analyzed.Secondly,the switch state of the dual inverter topology with a single DC structure is analyzed,and the switching model is established.Based on the switch model,the zero-sequence voltage and common-mode voltage in the dual inverter system are defined,and the influence of the zero-sequence current in the system are analyzed.The zero-sequence circulating current problem exists in a single DC dual threelevel inverter system.This paper improves two modulation strategies based on SPWM and SVPWM.The method effectively suppresses the zero-sequence problem in the system.When the switching device on the bridge arm fails to open,analyze the remaining output capacity of the system after the failure.The failure of the switch tube can be divided into two categories.When 1 tube and 4 tube on the bridge arm are faulty,the proposed modulation strategy can achieve full-load half-speed operation.When 2 tube or 3 tube on the bridge arm are faulty,the zero-sequence voltage can be superimposed to make the motor reduce load and slow down.For bridge arm-level failure,three topological reconstruction methods are proposed.The three methods have different fault tolerance and need to be further selected according to specific needs.For the three-phase motor stator winding phase-failure fault,firstly,the phasefailure motor is modeled and analyzed,and the torque ripple under the fault is analyzed.In order to reduce the torque ripple during the phase loss operation,the phase loss motor is controlled based on oriented rotor field.At this time,the torque ripple is effectively suppressed.Compensating the voltage of the remaining two phases effectively reduces the current distortion rate.Finally,on the basis of closed-loop control,the load capacity of the phase-loss motor is analyzed.MATLAB/Simulink simulation and hardware experiment platform are established in this paper.The correctness and validity of the control strategies are verified by simulation and experimental results respectively.