Direct Torque Control System Of Permanent Magnet Synchronous Motor For New Energy Vehicle Based On Predictive Algorithm Of Voltage Vector

With the development of economy and society,the automobile industry is facing two major problems: energy shortage and environmental pollution.Therefore,the development of new energy vehicle technology is an inevitable trend,and drive motor control is one of the core technologies of new energy vehicle technology.In this paper,we take the permanent magnet synchronous motor direct torque control(PMSM-DTC)as the research object,and expands a new predictive control strategy based on the traditional DTC system.The specific research contents are as follows:Firstly,this paper introduces the mathematical models of PMSM in three coordinate systems and their transformation.Combined with the mathematical models,it introduces the DTC strategy,introduces its basic principle,and controls stator flux and torque.Through the transformation of each coordinate system,the torque equation of PMSM-DTC is obtained.Based on the PMSM-DTC strategy,the effect of the voltage vector is first studied,and then the space vector modulation technology is introduced and described in detail.Studying the amplitude of fixed voltage vector selection strategy,analyze the effect of PMDM-DTC voltage vector selection system control under the action of amplitude of large voltage vector and amplitude of small voltage vector.Based on the control effect of two different amplitude of voltage vectors,an adaptive voltage vector amplitude selection strategy is proposed.Through the indicators of system’s dynamic and static,the correct voltage vector amplitude is selected.Simulation results prove that the selection strategy of adaptive voltage vector amplitude is better than the selection strategy of fixed voltage vector amplitude.Secondly,in order to obtain better control results,this paper presents a predictive control strategy of the variable voltage vector amplitude of the PMSM-DTC.In this strategy,the amplitude of the voltage vector is used as a variable.The values of stator flux and torque values at the next moment applied different amplitudes of voltage vector are obtained through the predictive equation.The amplitude of voltage vector that minimizes the cost function formed by the flux and torques’ relative error is selected as the optimal value,and the voltage vector to be applied at the next moment is determined.Finally,this paper studies the model predictive direct torque control(MPDTC)combined predictive control and DTC.In order to improve the performance of the system,virtual voltage vectors are used to increase the number of voltage vectors,and the improved MPDTC is studied in this paper.The simulation results of different control strategies are compared and analyzed.