Design Of PMSM Control System For Automobile Electric Power Steering

As a driving auxiliary equipment of automobile,electric power steering system(EPS)directly affects the driving performance and comforbility.Compared with BLDC,PMSM has the advantages of high efficiency,good performance in low speed,small volume,low torque ripple and low noise.So that it has obvious advantages using as the driving-motor of EPS.In this paper,a special PMSM with build-in resolver made by Nidec is used for EPS driving motor study.The driving-system and detecting-system for this PMSM is designed.And then a testing platform of EPS system is built and the performance of the system is tested.Firstly,the basic theory and control technique of PMSM are studied.And the torque-controlling system of PMSM is constructed based on the vector control strategy id=0-Then.the sensorless control system of PMSM is researched based on the low frequency injection method and the simulation tests are completed.According to the basic requirements of the EPS driving-motor,an EPS motor driving-system and a resolver rotor position detecting_system are designed,using dsPIC30F4011 as MCU.The motor driving-system includes MCU controller and related auxiliary circuit,power supply circuit,current detection circuit,fault protection circuit,driving and inverting circuit,human-computer interaction circuit and so on.The detecting-system is composed of MCU controller and auxiliary circuit,excitation signal generation and conditioning circuit,A/D sampling circuit,torque sensor and signal processing circuit and so forth.The software of driving-system includes the main program,PWM interrupt program,SPI interrupt program,PI adjustment program,speed calculation program,adaptive first order digital filter program and EPS control program,etc.The software of detecting-system mainly includes main program,input capture interrupt program,SPI data sending program and rotor angle decoding program.At the end of this study,the validity of the driving-system and detecting-system is verified by experiments.According to the actual EPS system,the testing platform of EPS system is built.The performance of the PMSM control system for EPS is tested,and the test results are analyzed.