Study On The High Speed Brushless DC Motor Control System Base On PWM Rectifier

High speed BLDC has the advantage of small physical dimension,fast dynamic response and can be directly connected with hi-speed load or prime motor,which make it widely used in various industrial fields.because of hi-speed BLDC has larger air gap smaller armature inductance,traditional PWM modulation will produce a great number of high frequency current harmonics which led problem like large torque ripple and serious motor heat.In the meantime traditional PWM modulation use the diode rectifier which cause harmonic pollution in electric power net.This paper mainly studies the control strategy of hi-speed BLDC,and for the hereinbefore problems,a new controller topology is proposed.Firstly in this paper,the mathematical model of the BLDC is analyzed and simulation model is buieded.The traditional sensorless control method on hi-speed BLDC is simulated and the cause of torque ripple is analyzed;the advantages of BUCK converter and three phase six state open mode are introduced from two aspects of current ripple suppression and torque ripple suppression,the modeling and Simulation of the control system are also given,the expected results are obtained and the disadvantages of the traditional thyristor controlled rectifier are pointed out at the same time,the harmonic harm to the power grid is analyzed;at last,the analysis and comparison of the three phase voltage source rectifier and current mode rectifier are presented,the principle of signal modulation and the principle of indirect current control of three-phase PWM rectifier are introduced,the main circuit parameters are designeda new type of high speed brushless DC motor control system based on indirect current control PWM rectifier is proposed.Using the IGBT device to replace the diode on frequency converter rectifier side,apply the power factor correction technology,reduce the pollution on the grid.Using busbar current modulation on the inverter,driving bridge-arm use 3-phase 6-state open as driving Mode,realize the control on a 10000r/min,10 kw BLDC.The results of Simulation on matlab show the topological structure as proposed can effectively improve the network side power factor and reduce the motor armature winding harmonic and motor torque ripple.