Research On Complex Vector Current Control Strategy Of Permanent Magnet Synchronous Motor For New Energy Vehicles

With the continuous growth of the new energy vehicle market,permanent magnet synchronous motor,as one of its key technologies,has attracted much attention.However,when new energy vehicles use permanent magnet synchronous motors,their shaft current control is easily coupled with each other,and the coupling further intensifies as the speed increases,thereby affecting the dynamic adjustment performance of the motor.This is due to the cross influence between d-axis current control and q-axis current control during the operation of permanent magnet synchronous motors.Therefore,the core to solving this problem lies in the decoupling control strategy,which solves the current coupling problem and improves the control effect of permanent magnet synchronous motors.With the popularization of current control,the emergence of control delay will greatly enhance the coupling of shaft current,thereby greatly reducing the system’s responsiveness and stability.Therefore,in the control research of permanent magnet synchronous motors,solving the problems of cross coupling of shaft current and control delay is a difficult point that must be overcome.This article selects permanent magnet synchronous motors as the research object,taking the high-performance requirements of new energy vehicles as the background,and proposes solutions to improve the control performance of permanent magnet synchronous motors.The specific content is as follows:This article first analyzes the motor structure and operating principle of permanent magnet synchronous motors,and compares the differences between surface mounted permanent magnet synchronous motors and built-in permanent magnet synchronous motors.Finally,the built-in permanent magnet synchronous motor was chosen as the research object for further research.Next,for the built-in permanent magnet synchronous motor,this article derives the mathematical model of the motor in the ABC three-phase stationary coordinate system,and based on the principle of coordinate transformation,further derives the mathematical model of the motor in the two-phase rotating coordinate system coordinate system.Then compare and analyze different motor control strategies in vector control methods,and select the_di=0 method in vector control methods to drive and control the motor.In addition,this article also compares and analyzes the current research status of current loop decoupling methods and delay compensation strategies.These research results are of great significance for improving the control performance of built-in permanent magnet synchronous motors and optimizing their control strategies.At the same time,these research results also provide certain reference value for the control research of other types of permanent magnet synchronous motors,and have certain theoretical and practical significance.Secondly,this article selects the built-in permanent magnet synchronous motor as the power core and conducts in-depth research on its current control technology.After adopting vector control,although static decoupling of current can be achieved,the impact of dynamic coupling cannot be solved.Therefore,this article focuses on current control technology,analyzes the principle of current loop coupling,and compares and analyzes the decoupling principles of traditional feedforward decoupling controllers and complex vector decoupling controllers.Based on these analysis results,this thesis proposes a complex vector decoupling controller that can reduce the original motor system to a single input single output system.This controller achieves current decoupling through the principle of zero pole cancellation,and has shown good performance in both experimental platforms and simulation simulations.Compared with traditional feedforward decoupling controllers,complex vector decoupling controllers can significantly improve the dynamic response ability,control accuracy,and robustness of built-in permanent magnet synchronous motors.Finally,based on the delay problem in digital control systems,the causes of digital control delay are analyzed and divided into two categories:position sampling delay and current sampling delay.A hardware ADC position sampling delay compensation method is proposed for position sampling delay;A low-speed single sampling and high-speed double sampling current sampling strategy is proposed to improve the current sampling delay problem,which is combined with practical applications.Finally,the dynamic performance of the system after delay compensation is demonstrated through an experimental platform,and the performance of the complex vector decoupling control combined with delay compensation strategy is better than that of the feedforward decoupling control system.In the final chapter of this article,a summary of the entire work is provided,and the problems and shortcomings in the research process are analyzed.Furthermore,the future development trends and research directions related to this article are prospected.