Research On The Control Method Of Weakening Magnetic Field Of Pmsm For Electric Vehicle

At present,with the improvement of people's living standard and the support of national macro policies,the level of automobile manufacturing industry has gradually developed rapidly.As a daily tool,automobile has been everywhere in life.By the end of2019,according to incomplete statistics,the number of vehicles in the world has reached as many as 1 billion,most of which are mainly internal combustion engines,which is also the main development trend of traditional automobile industry.However,in recent years,electric vehicles mainly driven by electricity gradually appear in our vision.The development prospect of electric vehicles is relatively broad,and the biggest advantage is to respond to the call of the construction of a national environment-friendly society.Therefore,the design of electric vehicles as the leading automotive industry has become an important task in the world.At present,the motor as the driving part of the vehicle has become one of the core components of the electric vehicle.The performance of the whole driving part and the product performance directly restrict the whole performance of the electric vehicle.The important link in the research of electric vehicle is to improve the driving part of electric vehicle.The traditional driving part of internal combustion engine vehicle mainly depends on the carbon compounds such as gasoline and diesel.In recent years,the original power of electric vehicle is driven by "electricity".There are three main types of electric motors used in the market: switched reluctance motor,permanent magnet synchronous motor and AC asynchronous motor.The control of electric vehicle is defined by the controller.Good controller directly determines the performance of electric vehicle,especially in speed control and efficiency.Up to now,the controller has been developing in several directions: stability dominating,high precision control,relatively simple hardware design and advanced control algorithm.Our country,as a big country of automobile manufacturing industry,has a relatively large amount of use of controllers.Many of the proprietary controllertechnologies for electric vehicles are imported from abroad.The controller algorithm developed by our country is not very stable.The main performance is that the motor control is not mature in the high-speed area above the rated speed,which is commonly referred to as "weak magnetism".One of the advantages of flux weakening speed regulation is that the torque output is relatively large when the speed is low,which is just in line with the behavior of overtaking or uphill climbing of electric vehicles on the highway.Under such background,this paper proposes the flux weakening control method of permanent magnet synchronous motor for electric vehicles,which is dedicated to improving the speed regulation control system of electric vehicles The system makes it play a better weak magnetic performance and has a certain engineering application value.The main research content of this paper is the research on the control method of flux weakening of permanent magnet synchronous motor for electric vehicle(1)This paper introduces the background and significance of electric vehicle research,puts forward the current development prospect of electric drive vehicle based on the traditional vehicle driven by internal combustion engine,analyzes the reasons that restrict the speed control system of electric vehicle,and puts forward a weak magnetic control strategy to improve the speed control performance of motor above rated speed.(2)Most electric vehicles are controlled by PMSM.The mathematical model of PMSM is analyzed,including the basic structure of PMSM,the principle of coordinate transformation and space vector modulation technology(3)In this paper,the current distribution strategy in the field weakening control technology is introduced in detail,that is,how to use the maximum torque current ratio(MTPA)technology to analyze the change of the current in the field weakening process of the direct axis and the cross axis,and how to use the voltage regulation method to describe the field weakening control,at the same time,the method is verified by simulation.(4)In view of the inadequate current decoupling in the voltage regulation method,the internal model decoupling control is used instead of the traditional PI decoupling control,and a disturbance observer is designed to observe the current in real time and then adjust other parameters in detail,and a better control effect is obtained.(5)The current,voltage,leading angle and speed fluctuation caused by the hard switch of the weak magnetic speed regulation are improved in detail.An adaptive leading angle is designed by using the multi model adaptive control to solve this problem,and the method is verified by simulation.