Research On The Robustness Of The Control Of Permanent Magnet Synchronous Motor Used In Electric Vehicle

In the current world in which caused by the environment and energy problem increasingly urgent need to solve, with electric vehicles to replace traditional fuel vehicles become an inevitable trend of future development. With modern electronic technology, control technology and the mature development of new type of permanent magnetic material technology, Permanent magnet synchronous motor (PMSM) could have limitless applications in the field of electric vehicle drive due to the desirable features such as small volume, high efficiency, high power density, larger torque to inertia ratio and wide speed range. This proposed research is directed to the robustness of the control technology for PMSM drive system used in electric vehicle.First of all, the structure and classification of permanent magnet synchronous motor are discussed, According to the application requirements of the electric vehicles, interior permanent magnet synchronous motor (IPMSM) is selected as the research object. Then introduces the relationship betweens the three kinds of coordinate transformation and the mathematical model for IPMSM in the d-q rotating coordinate. On this basis, the PMSM vector control scheme and the realization of the space vector modulation (SVPWM) technology are studied. The double closed loop system of PMSM was analyzed, and the current loop and speed loop are designed respectively.Secondly, aim at demanding of the higher requirement of speed dynamic response in the control system of permanent magnet synchronous motor, to replace the system of the conventional PI speed controller with the improved fuzzy controller.The design process and methods of the improved fuzzy controller is studied. The simulation results show that the improved fuzzy speed controller not only make the system has better dynamic tracking property to speed change, but also make the system have a certain amount of robustness.Thirdly, in order to improve the robustness of the control system of permanent magnet synchronous motor, on the basis of the maximum torque per amper (MTPA)control, aiming at the shortcomings of the traditional control strategies using back and forth search method, is put forward to the golden search method. By analysis of the simulation shows that the algorithm has faster speed in search the operation point of the maximum torque per amper control, has stronger robustness with the changes to the working state and motor parameters, and increased the maximum torque per amper control’s engineering applicability.Finally, in order to improve the robustness in current loop of the control system of the permanent magnet synchronous motor to external disturbance such as load change, to replace the traditional PI current loop of system with the improved sliding mode controller. Study on load disturbance robust sliding mode controller design process and methods. The simulation results show that the proposed controller not only can improve the control quality of system, but also the system has better dynamic tracking characteristics of the load change and has stronger robustness.