Research On DTP-PMSM Fault-tolerant Control Based On Current Prediction And Harmonic Suppression

Compared with the traditional three-phase permanent magnet synchronous motor(PMSM),the dual three-phase PMSM(DTP-PMSM)has greater advantages in providing high power,reducing torque ripple and fault-tolerant control,making it suitable for electric vehicles,ships,aerospace and national defense and other occasions with high reliability.In this paper,the double Y phase shift 30°electric angle DTP-PMSM is taken as the research object,and the following research work is carried out on its beatless current prediction control,harmonic suppression and fault-tolerant control strategies.Firstly,the mathematical model of DTP-PMSM is constructed,and the mathematical model of DTP-PMSM under the six-phase stationary coordinate system is analyzed and studied by double d-q coordinate transformation and vector space decomposition(VSD)coordinate transformation theory,respectively,and the mathematical model under the two coordinate systems is obtained,considering that the double coordinate transformation does not fully reflect the characteristics of DTP-PMSM multiple degrees of freedom and cannot effectively control the harmonic components.Finally,the VSD coordinate transformation method is selected for analysis.Secondly,for the pulse width modulation technology,the traditional two-vector SVPWM algorithm and four-vector SVPWM algorithm of DTP-PMSM are analyzed,and the three-phase decoupling PWM algorithm and the double-zero-sequence injection PWM algorithm are introduced,because the traditional two-vector SVPWM does not consider the x-y influence of voltage synthesis on the subspace on the system,which will lead to harmonic loss,so the four-vector SVPWM algorithm is selected in this paper.Thirdly,in view of the problems of slow response speed and low steady-state accuracy of traditional PI control,it is proposed to introduce Deatbeat Predictive Current Control(DBPCC)into the DTP-PMSM four-dimensional current control system,and replace the PI controller with the non-differential current prediction controller in the fundamental subspace current inner loop,while considering the influence of x-y subspace harmonic components.A quasi-proportional resonant(PR)controller is introduced to replace the PI controller in the x-y subspace,and the harmonic component is suppressed,and the effectiveness of the algorithm is verified by simulation.Finally,aiming at the fault-tolerant control performance of DTP-PMSM,the magnetomotive force and electromagnetic torque of DTP-PMSM before and after the fault are analyzed,and based on the current solving principle of constant rotational magnetomotive force,the two optimization indicators of stator copper minimum and torque output maximum are selected,and a fault-tolerant control scheme based on current hysteresis control technology is constructed,and the effectiveness of the fault-tolerant control method is simulated and analyzed.Then,taking the constant total magnetomotive force before and after phase failure as the constraint,the coordinate transformation matrix and dimensionality reduction mathematical model of the motor after single-phase phase failure are derived,and the axial coupling is reduced by secondary coordinate transformation,and then a DTP-PMSM dimensionality reduction fault tolerance control strategy combining beatless current prediction control and quasi-proportional resonance control is proposed,and the fault-tolerant control strategy is realized with the minimum stator copper consumption as the goal,and a simulation model is built to verify this fault-tolerant control technology.The results show that this method can keep the motor running stably after the phase failure occurs,and has fast dynamic response and harmonic suppression ability.