Control Strategy Of BLDC Motor Drives Method Based On Quasi-Z-source Converter For Commutation Torque Ripple Reduction

Brushless DC motors (BLDCM) are widely used in many applications, such asindustrial and household products due to their high output torque, fast dynamic response,small moment of inertia, high reliability, simple control. For high precision system, thetorque ripple is an important indicator to measure the performance of the brushless DCmotor. The torque ripple causes cogging torque, non-ideal trapezoidal Back-EMF andcommutation torque ripple. For a sophisticated design of the brushless DC motor,commutation torque ripple is the main part of the torque ripple, sometimes commutationtorque ripple will account for50%of the average torque. This paper presents a novelcircuit topology that regulating the dc bus voltage for reducing commutation torqueripple based on quasi-Z-Source converter.This paper analyzes the causes of commutation torque ripple briefly, presents thenew approach of torque ripple suppression by adding an accessorial dc converter, andintroduces the advantages and disadvantages of the Z-source inverter and fourquasi-Z-source inverters. The accessorial dc converter uses voltage fed qZSI withcontinuous input current.Simulation model was constructed in the MATLAB/Simulink circumstance. Theexperiments were accomplished according to different circuit parameters. Simulationand analysis are made. The result shows that, this circuit has a significant effect ontorque ripple suppression. Torque ripple can be reduced to below2%of the averagetorque. And the average output torque of the motor was properly improved.A motor controller based on quasi-Z-Source net is designed. Hardware modulesincluding circuit design and parameters calculation of the controller are described indetail. Control strategy is illustrated with hardware. Compared with the phase currentwaveform without suppression strategy, the experiment shows that, this circuit has asignificant effect on torque ripple suppression.