Research On Control System Of Permanent Magnet Synchronous Motor For Electric Vehicle

As Chinese economic and social development has entered a new stage,the construction of ecological environment and the improvement of energy efficiency are gradually becoming the concerns of the whole society.New energy vehicles powered by electric motors are also showing rapid development along with the guidance of national policies.Especially with the continuous development of power electronics,control theory and the improvement of the performance of new rare earth permanent magnet materials,the compact structure,light weight,high efficiency and energy saving permanent magnet synchronous motor(PMSM)has been rapidly developed.With the large-scale application of PMSM,the field oriented control(FOC)theory,which is the mainstream control method of PMSM,has also become a research hotspot.Voltage Space Vector Pulse Width Modulation(SVPWM)technology enables higher DC bus voltage utilization and reduces switching losses and torque ripple with a three-phase inverter and motor perspective.The paper comes from a company's electric vehicle motor controller development project.The design of the control system is based on the DSP chip TMS320F28335 introduced by Texas Instruments.Firstly,the mathematical model of PMSM is established and the mechanical characteristics of the motor in the rotating coordinate system are analyzed.Then,the principle of vector control is introduced in detail and the vector control algorithm of PI double closed loop control is selected by comparison.Furthermore,the SVPWM technology used to drive the inverter is introduced in detail and the detailed algorithm design process based on TMS320F28335 is given.Next,the vector control algorithm model of the control system and the fault protection algorithm model are developed on the MATLAB/Simulink platform and the code is automatically generated.The automatically generated application layer code is integrated with the underlying handwritten code in the integrated development environment CCS,and the complete controller software file is obtained.At the same time,the development of the hardware system with TMS320F28335 as the main control chip is completed on the DXP platform.According to the system requirements and the interface definition of the software,the component selection and design work of the peripheral circuit of the main control chip was completed,and finally the PCB was produced.Based on the above work,the hardware-in-the-loop(HIL)and model-in-the-loop(MIL)systems for real controller and control algorithm models were developed based on the laboratory dSPACE semi-physical simulation system and MATLAB/Simulink platform separately.What's more,The system control function and fault protection function were tested by HIL and MIL.The test results show that although the control effect of the real controller is little different from the offline simulation result in MIL,the overall effect meets the design requirements.The verification of HIL and MIL profoundly proves the rationality of the control system design.