Design Of Motor Controller For High Speed Pure Electric Vehicle

In recent years,the energy crisis has further intensified.Both the government and the market place more emphasis on electric vehicles,so pure electric vehicles have vast room for improvement.Increasing the research and development investment of the motor drive system and improving product performance can bring better profits for the enterprise.The electric motors of electric vehicles are less noisy and more environmentally friendly than traditional fuel engines,especially when they use the linear power of the motors when starting and accelerating.As one of the three core systems of electric vehicle battery,electric drive and electric control,the electric drive system's performance is closely related to the performance of the whole vehicle.PMSM has the advantages of easy installation,low noise and pulsation,and high torque.It is more suitable for pure electric vehicle applications.Firstly,this dissertation establishes three mathematical models of PMSM in different control stages based on the structure and working principle of permanent magnet synchronous motors.Using the relationship and characteristics of the motor parameters,this dissertation derives the expressions of voltage,current,flux linkage and torque.PMSM analyzed by three kinds of coordinate system transformation process,transformation is given Clark,Park transformation process and the conversion formula.This method simplifies the modeling and control of PMSM.In addition,by analyzing the inverter form,sector judgment basis and sevensegment SVPWM,vector control combined with field weakening control is adopted.This method improves the control efficiency and better solves the need for motor speed expansion.Secondly,this dissertation builds a hardware system with TMS320F28035 chip as the core.By analyzing the DC-DC power supply and power requirements of the controller,the design and manufacture of the switching power supply with LM5085 as the core is completed.Solved the problem of high power and wide voltage of the core power supply of the controller.By analyzing the drive capacity requirements of the inverter in parallel with multiple tubes,the power drive circuit design is completed,which improves the drive capacity of the inverter,reduces losses,and improves efficiency.According to the vector control closed-loop control strategy requirements of the controller,non-contact high-current detection is realized.Also completed the remaining functional circuit design and controller production and construction.By analyzing the required functions and logic of motor control,vector control is taken as the basic framework.This dissertation combines the PI regulator,field weakening control,MTPA,SVPWM to complete the design and implementation of the control system software.Finally,a test motor with a rated power of 1kW was used as the verification object to complete the laboratory test of the controller,and the test results were good.A test motor with a rated power of 8kW was used as the control object to complete the no-load and bench test under the test bench environment.The test results show that the motor has good speed regulation performance under no-load and bench-load test.The motor torque ripple is small and the response is rapid.The controller meets the expected design requirements.