Research On Fractional Order Control Strategy Of Permanent Magnet Synchronous Motor In EV

Electric drive control system is the core component of electric cars.Permanent magnet synchronous motor(English abbreviation:PMSM)has become one of the main motor of electric vehicle drive system.Among them,the excellent of PMSM control strategy is effective to improve the performance of electric vehicle drive that is also one of the most important aspects of the research and development of high performance motor drive control system.At present,PMSM of electric car adopts speed loop and current loop of the double closed loop vector control structure,mainly around the speed loop control study,and most of the proposed control method for the integer order,the vehicle running is hard to guarantee the motor output performance and good robustness in complex condition.Because the back EMF(electromotive force)is the main interference in current loop,and current loop is the core of the double closed loop control system,and its control performance is about driving system and the dynamic characteristics of speed loop performance,which will affect the overall quality control system.However,the existing modeling design mostly ignore the back EMF of the current loop.In recent years,the theory of fractional order control application combined with PMSM control research,can obtain better control performance and robustness when it compared to the traditional integer order control strategy.Existing control research of electric car PMSM are less considering the different actual working condition when the electric car driving.Therefore,this paper will briefly introduce the PMSM mathematical model,the theory of fractional calculus,and establish the mathematical model on the basis of the electric car and PMSM mathematical model,designing current loop with considering the effect back EMF,modeling based on after the first inner loop control system design principle,developing electric cars double closed-loop fractional order control strategy research,including:1,The fractional order adaptive control method research on EV PMSMBased on the travel equation of electric vehicle and the mathematical model of permanent magnet synchronous motor,a fractional adaptive control method of permanent magnet synchronous motor for electric vehicle is proposed according to the system stability theory.The method uses the fractional order adaptive law to adjust the gain parameters of the speed loop controller.The simulation results of double closed-loop control system of electric vehicle speed-current show that compared with the integer order control situation,the electric vehicle driving system of fractional adaptive control method has the advantages of fast control speed,high precision and robustness with the condition of vehicle acceleration,climbing,speed change and vehicle quality parameter change.2,Double closed-loop fractional order control method research on EV PMSMCurrent loop is the key core to the permanent magnet synchronous motor control system,which is a link within the speed loop.In order to improve the current loop of permanent magnet synchronous motor control system performance,put forward a method about current loop fractional control with considering the electric potential impact.According to the traditional pole zero cancellation method,determine the order by index function optimization searching.Speed loop is the key to achieve high precision rotating of permanent magnet synchronous motor,which is the performance of the electric car driver.Designing a speed loop fractional controller about fractional order double integral FOPI controller based on fractional order current loop which has been designed above,according to the frequency domain design criterion.The results of simulation are given first with the traditional speed loop PI controller,using comparative analysis the performance of speed of response under different current loop control.Research has shown that the fractional double integral FOPI controller has faster speed response,and compared with the integer order control,fractional order control has better dynamic response performance.Then the results of simulation are given with current loop fractional order control,giving the figure of climb performance analysis with speed loop fractional control.The simulation results show that the fractional order control has better load disturbance resistance,and improve the robustness of the system,in line with the requirement of modern electric vehicle driving comfort.The research results provide useful theoretical reference for exploring the control strategy of high performance PMSM control system for electric vehicle and improving the performance of electric vehicle drive control system.