| Permanent magnet synchronous motor(PMSM)has the advantages of simple structure,high operation efficiency and low noise.Therefore,it is widely used in aerospace,electric vehicle and other fields.With the continuous development of China’s industry,it has become a hotspot of scholars to enhance the control accuracy and operation reliability of PMSM.This thesis takes the double Y phase shifted 30 six phase PMSM as the research object,and studies its current predictive control and fault-tolerant control technology.This thesis expounds the research status of polyphase motor control technology,analyzes the research contributions made by domestic and foreign scholars for polyphase motor,and summarizes and analyzes the development status of polyphase motor current predictive control technology and fault-tolerant control technology at home and abroad.In order to solve the highly coupled mathematical model of six phase PMSM in natural coordinate system,this thesis build the mathematical model of six phase PMSM based on double d-q coordinate transformation and vector space decomposition(Vector Space Decomposition,VSD)coordinate transformation.This thesis focus on the basic principle of model predictive control strategy,based on which,a large amount of calculation in continuous set model predictive control strategy is pointed out,and the finite set model predictive control strategy is selected to control the operation of six phase PMSM.An improved three vector current predictive control(MPCC)strategy for six phase PMSM is proposed to shortcut calculation and suppress current harmonic and torque ripple.In this method,virtual voltage vector is constructed.The system simulation model of six phase PMSM current predictive control is built,and the improved three vector current predictive control strategy is simulated and analyzed to verify the correctness and feasibility.The fault-tolerant control strategy of six phase PMSM based on constant total magnetomotive force is studied,and the problem of large current harmonic generated by the fault-tolerant control strategy is pointed out.Combined with the motor vector control theory,the mathematical model of six phase PMSM with one phase disconnection deduced,and a new coordinate transformation matrix is constructed to realize the decoupling of motor variables under fault,based on which,the fault-tolerant control strategy on the basis of dimensionality reduction decoupling is proposed.In order to minimize the copper consumption or maximize the electromagnetic torque,the current constraints are deduced.The simulation model is built and the results show that the performance of six phase PMSM with the fault-tolerant control strategy of dimension reduction decoupling is higher.The hardware circuit of the experimental platform is designed,the software program of the six phase PMSM control system is compiled.the system experimental platform is built and experiments verify the feasibility of the control strategies proposed in this thesis. |
