Fault Diagnosis And Fault-tolerant Control Of Six-phase Permanent Magnet Synchronous Motor Drive System

Compared with the traditional three-phase permanent magnet synchronous motor（PMSM）,the multi-phase PMSM has its unique advantages in improving power,suppressing torque ripple and fault-tolerant control.Suitable for occasions with high reliability requirements such as ships,aerospace,national defense,etc.However,as the number of phases increases,the probability of failure of a multi-phase motor system also increases,with drive system failures accounting for the largest proportion.This dissertation takes thedouble-Y phase shift 30^°six-phase PMSM as the research object,the fault diagnosis method and the corresponding fault-tolerant control technology are studied.The six-phase PMSM mathematical models of two coordinate transformation methods,double d-q and vector space decomposition（VSD）are established respectively.Considering that the double d-q transformation does not realize the control of harmonic components,the VSD transformation method is finally adopted.The PWM modulation technology is studied,and the two-vector SVPWM and four-vector SVPWM algorithms commonly used in six-phase motors are analyzed.Considering that the two-vector SVPWM cannot suppress the current in the harmonic plane,the four-vector SVPWM is finally determined.A fault diagnosis method based on vector space decoupling（VSD）is proposed.According to the VSD decoupling inverse transformation and the open-phase constraint conditions,the open-phase fault index is determined.The fault indicator is optimized from the perspective of preventing misdiagnosis and improving reliability,and the open-phase fault can be diagnosed within a fundamental wave cycle.In addition,the current trajectory of the harmonic plane after the switch failure is analyzed,the BP neural network is used to identify the harmonic plane current trajectory of different types of switch faults,and the diagnosis algorithm simulation model and matlab neural network program are built.Verify the correctness and feasibility of the diagnostic method.Aiming at the constant constraint conditions of the total magnetomotive force before and after the phase failure,the coordinate transformation matrix and the dimensionality reduction mathematical model of the motor under the phase failure failure are derived.The dimensionality reduction and fault-tolerant control aiming at the minimum stator copper loss is realized;In addition,the magnetomotive force and electromagnetic torque of the motor before and after the fault are analyzed,and the residual error-tolerant current reference value corresponding to the two current optimization goals under the condition of constant magnetomotive force is solved.A simulation model was built to verify the two fault-tolerant control technologies.The hardware circuit with TMS320F28335 as the main control chip was designed,the corresponding software program was written,set up an experimental platform for software and hardware debugging,The correctness of the theory is verified.