Research On Servo Control Technology Of Permanent Magnet Synchronous Motor With Ebooster On Vehicle

With the development of electric vehicles,electronic booster system has gradually replaced the vacuum pump power system of traditional vehicles with its advantages of safety,energy saving and intelligence.Permanent magnet synchronous motor(PMSM)has been used as the brake execution unit of electronic booster system due to its high power density and good dynamic performance.Therefore,it is very important to study the controller and algorithm of PMSM in electronic booster system.Firstly,this paper introduces the research status of electronic booster system and control technology of PMSM.The structure and mathematical model of PMSM are described.Vector control technology,current feed forward decoupling method,SVPWM modulation technology and a dead-zone compensation method based on deadzone time are introduced.Secondly,set up electronic booster hardware platform of the control system of PMSM.The main chips selected and how to cooperate with them are introduced.And carry on the software program design,elaborated the main program,e Cap interrupt and ADC interrupt subroutine software development flow.Thirdly,in order to improve the signal accuracy of the electronic booster motor control system,the acquisition and processing methods of the rotor position sensor and the brake pedal push-rod displacement sensor signals are designed according to the actual situation.Aiming at the rotor position sensor,a hardware filter circuit was designed.According to the signal characteristics,a method to obtain the initial error of the rotor was proposed.The rotor Angle was decoded by PLL and verified by simulation and experiment.For the brake pedal push-rod displacement sensor,the e Cap module of the main control chip is used to obtain its PWM wave and calculate the duty cycle.A table looking up method is proposed to convert the duty cycle into a given signal corresponding to the motor position ring.Finally,in order to solve the speed overshoot problem of the speed regulation system of the electronic power assist motor,the energy exchange characteristic model of the electronic power assist motor was derived on the basis of the mathematical model of the synchronous rotation coordinate system.The feedback control strategy of rotor kinetic energy as the control quantity of outer loop is designed,and the rotor kinetic energy as the control quantity of outer loop is used for vector control.The detailed design method of current loop and rotor kinetic energy loop is given.Compared with the traditional load side power compensation method,considering the influence of friction on the load side power,a load side power compensation method based on the expanded state observer is proposed,and the convergence of the method is proved.Combined with the rotor position sensor,a three-loop control method with the outermost position loop is designed.The effectiveness of the algorithm is proved by experimental comparison and analysis.