Research And Design Of Sine-wave Dirving For Brushless DC Motor

Brushless DC motors with high efficiency, fast, low noise level, speed characteristics,excellent, low cost, ease of maintenance and other advantages are widely used. Withoutcontroller for brushless DC motor, so it’s an important study on control technology ofdomestic and foreign researchers. Traditional six State generally use three-phase brushless DCmotor driven by square wave conduction, this drive is simple to program, debug, significantadvantages such as torque, while torque ripple caused by noise, poor speed performance,efficacy and low defects.As single tablets machine, high performance microprocessor cost of constantly reduced,based on BLDC motor ontology itself by inherent of Hall rotor location sensor, used voltagespace vector (SVPWM) technology achieved sine wave output in low hardware cost, reachedno brush DC motor of low noise drive and wide range adjustable speed of purpose, whilegreatly improve has this electromechanical integration drive system of marketcompetitiveness.This paper sine wave controller adopts PI speed closed-loop control, current loop andthree phase lock loop controller output strategy; Improved the calculation method of hallsignal for motor speed; Using the harmonic injection method of SVPWM modulation, intothree times in a certain proportion in SVPWM modulation harmonic, improve the utilizationrate of power supply voltage;360degrees to a traditional electric cycle modulationimprovement for all electricity normally closed cycle in120degrees,240degrees of sinewave modulation output; For motor control system for motor parameters have strongdependence of defects, the controller uses adaptive system solutions; Analysis of variablespeed rotary motion model calculating motor unit time required Angle, using the method ofthe rotor initial position, the current closed loop and booster l frequency software strategy,implementation step by step motor launch strategy.Experimental results show that the speed control system is running smooth, current jittersmall torque ripple small operation demonstrated the feasibility and correctness of thismethod, control program scope more broadly. Among them, the three closed-loop strategiesand improvement of motor rotate speed calculation method is effective in reducing torqueripple, the motor deceleration over a smooth, smooth; Improved modulation method,effectively reducing the switching frequency, extending the life of electronic switches;Adaptive system solutions and calculate point motor units start policy can effectively improvethe adaptability of the system to the motor, become motor characteristic curve makes the bootprocess.