Design And Realization Of Brushlcss DC Motor Control System Based On MCU

Instead of mechanical commutator for DC motor, Brushless DC motor used electroniccommutator. And brushless DC motor extended the effective using time of a motor and eliminatedsome problems caused by the mechanical commutator, such as electromagnetic interference, brushwear, frequent maintenance and etc. At the meantime, brushless DC motor inherited a fewadvantages from DC motor, like wide speed range, large torque, stable operation, low noise, andhigh power density,there is great significance in researching BLDCM control system.First, based on the related domestic and overseas research literatures, this paper describes thecharacteristics and the development process of the brushless DC motor; analyses the body structureand working principle; elaborates the relationship between the rotor position and the motor phasewinding conduction sequence; introduces the installation of the motor Hall position sensor. Sincethe computer simulation model of a brushless DC motor control system was built, this thesis alsoputs attention on the closed-loop motor speed system and speed, current dual closed-loop system bythe method of simulation.Then, according to the speed control principles of the brushless DC motor and the speed controldemands of the control system, this paper shows the modular design scheme of the system hardware.The system was divided into two parts, the control circuit and the power circuit. The core processorwas selected as uPD78f1213microcontroller of NEC Company and the inverter unit Intelligent wasdecided as Power Module IPM from Fairchild Company. The key point of the research focused onthe design of the processor protection program, the design of the switching power supply intelligentpower module protection mode and the drive circuit design. Referenced on the control algorithm inthe simulation model, the software design was achieved with the speed closed-loop control systemregulated by the PI algorithm and speed-current double closed-loop control system in the processor.According to user needs, the Labview design monitor interface was used, and as the auxiliarytool of the system debugging, the quantity of states, such as the current and the speed, weremeasured in the motor running progress. The efficiency of the control algorithm and the wholesystem debugging was improved a lot.Last, by the whole system debugging, the experimental results show the design scheme isscientific, reasonable, comprehensive and stable, which reaches the desired functional requirements.