Study On Soft-switching Techonlogy Of Quasi-Z-Source DC-DC Converter Used For Torque Ripple Suppression On Brushless DC Motor

Brushless DC motors(BLDCM)are widely used among many fields,such as aerospace industry,national defense,industrial control,automotive electronics and home appliances due to their big torque output,high efficiency,superiority in speed adjustment,long lifetime and high reliability.But the brushless DC motor driven with square wave current has some torque ripple issues.In speed control systems required high stability and torque control precision,the torque ripple restricts BLDCM application.In recent years,some methods dynamically adjusting the DC bus input voltage of inverter during commutation by the added pre-stage DC converter for torque ripple reduction have appeared.This paper expounds several reasons for the torque ripple of BLDCM and analyzes the commutation torque ripple suppression strategy.Quasi-Z-source DC-DC converter with soft-switching technology is proposed for commutation torque ripple reduction.The principle analysis of new topology is presented.And simulation based on MATLAB/Simulink was accomplished.Then,simulation platform of commutation torque ripple suppression system based on quasi-Z-source DC-DC converter with soft-switching technology was built in MATLAB/Simulink.And the simulation result was analyzed,showing effectiveness of the commutation torque ripple reduction system.The torque ripple was reduced from about 20% to 5%.Finally,a BLDCM commutation torque ripple reduction system experiment platform was built.The detailed design including hardware structure,design method and control algorithm were provided.The experiment was finished on the torque ripple reduction experiment platform.And the experiment data was imported to upper computer for analysis validating that the torque ripple reduction system is effective.