The PI Parameters Self-turning For PMSM Servo System

With the rapid development of power electronic technology, the microprocessing technology,rare earth permanent magnet materials, semiconductor technology, control theory and motortechnology, The Permanent magnet synchronous motor which has many advantages such as small size,big air gap flux density, big ratio of torque capacity and high efficiency has gradually become themainstream of motor selection for servo system.The Vector Control strategy and its development makes the permanent magnet synchronousmotor control performance improved significantly. The structure of PMSM vector control systemusually employ tow nested loops, with the inner loop implement the fast current control and the outerloop realizes the speed adjust. The inner and outer loop controllers generally adopt PID regulator forits simplicity, stable performance and high reliability. The performance of the PID regulator dependson the parameters of the PID regulator. Therefore, high-performance servo drive system should havethe self-tuning function of the controller parameters. This paper focuses on the research of self-tuningPI parameters for the PMSM servo system.Firstly, Surface Mounted PMSM mathematical model is analyzed, control strategies areelaborated, the id=0current control scheme is determine, then simulation model of the PMSM ACservo System based on vector control strategies is built using control block diagram of the systembased on MATLAB/Simulink environment.Secondly, the article introduced several PI parameter tuning method by classifying them intooffline and online two parts. By analyzing the advantages and disadvantages of each program, thepaper selects a genetic algorithm for PMSM servo system speed loop and current loop PI parametersfor offline self-tuning, and uses on-line self-tuning fuzzy PI regulator to tune the speed loop PIparameters on line. The feasibility of both methods are verified through MATLAB modeling andsimulation.Finally, system experiments are finished in a2.3kW PMSM SERVO platform, genetic algorithmsand fuzzy PI regulator program are written in the hardware and software environment with theFreescale’s high performance DSP chip MC56F8346as the core of to PMSM servo system.Experimental results demonstrate the feasibility of the algorithm: using the genetic algorithm offlinetuning of PI parameters improves system speed response, steady state accuracy; using the fuzzy logicon-line tuning for the speed loop makes the system more robust than the traditional system whendisturbance appears.