Research On Control System For Brushless DC Motor Drive

This paper mainly discusses the structure, working principle and main merits of Permanet magnet BLDCM. It has a comparation of four types of motors on their structure reliability, efficiency, the performance of speed adjustment, power volume ratio, manufacturing cost, controller cost. etc. It also points out the developing direction of permanent magnet BLDCM. No position sensor controlling of the permanent magnet BLDCM has been a hotspot. There are many ways to test the rotor's position, but the main tendency is from sensor method.ML4428 is a typical permanent magnet BLDCM controller without position sensor; it is an advanced high integrated controller, which was described in detail in this paper.Torque ripple is a main limitation of permanent BLDCM, which is mainly coused by electromagnetism, current direction exchangement, armature response, alveolus effect and mechanical manufacturing. The main methods to weaken torque ripple include mechanical method and electrical method. This paper mainly discuses phase current's wave form with PWM control method, and then put forward moving current phase method to weaken torque ripple when the motor is in low speed.This paper also sets up the voltage equation, torque equation, state equation and equivalent circuit, and then builds the model for the permanent magnet BLDCM by Matlab/PSB. The difficulty of motor's omit-voltage is solved by S-function in the simulink tool of Matlab. The computer simulation results show that the BLDCM model runs steadily with good dymic, static speciality. Which provide now ways for motor designing, manufacturing the experiment of control system.The main work of this project is the BLDCM control system designs, tests and experiments based on 80C196KC. Hardware designs include the main electrocircuit and control electrocircuit designs. The main electrocircuits include power supply, three-phase transducer, rotor position sensor, energy release loop. The cortrol electrocircuits include control chips, protect electrocircuit system watch, keyboard and displays, drive electrocircuit, electronic phase change, etc. The software designs include program design, motor rotate speed M/T measurement, integral separation and anti-saturation PI adjuster, the software implement of PWM waveform, phase-change control.Finally we did experiments on new products of a certain motor company based on the equipments of our laboratory now. The experiments include high speed and low speed tests, the low speed tests include phase move and none move parts, compared with the emulator they are inosculate.