Control System Design And Research Of BLDCM Based On The DSP

With the development of permanent magnet material, power electronics technology,control theory and microprocessor technology, BLDCM was widely used in the field ofautomobile, spaceflight, household appliances for it advantages of high efficiency, long life,low noise and well speed-torque character. But the application of BLDCM inhigh-performance occasions was limited for it poor operating performance, which can beimproved with the help of advanced control strategy. So it is also the research purpose andsignificance of this paper.The main emphasis of control technology of BLDCM was focused on three aspects:speed control strategy, technology of inhibiting torque ripple and sensorless technology.Thispaper was focused on the firist two aspects and completed the following work:(1) Designed an fuzzy PID controler according to the response characteristic of the speedloop on BLDCM and combination of fuzzy control and PID control.The simulation resultsindicates that the fuzzy PID can improve robustness of BLDCM,shorten rise time and reducestable error.(2)Propose the optimum time-share commutation theory base on the analysis of theeffect, which case by non-ideal back EMF and commutation process, on commutation torqueripple. At the same time, make an analysis of characteristic of torque and flux linkage observesegment of direct torque control (DTC) and comfirm timeshare moment and length accordingto the results of torque observe.At last, design a DTC model,which without flux linkage, usingoverlapping commutation base on torque observe.(3)Combine the result of the output signal of speed loop after PWM-ON modulation andthe output phase signal of DTC as the basis of phase commutation.The results of simulationbase on MATLAB/SIMULINK and experiment indicate that the control system design by thispaper is not only effectively inhibit torque ripple and speed ripple,but also with a simplestruture and strong practicability.(4)Constructs an experimental platform of BLDCM base on DSP,which include design ofhardware circuit and software. In view of weakness of a signle main program loop softwarein the field of real time,reliable,expandability and maintainabilit,this paper design a control software base on realtime operating system U/COS-â…¡ and the results of experiment indicatethat the software ran stably and deal with the motor control tasks well.