A Simulation Research In Torque Ripple Reduction In Brushless DC Motor Drives Based On Buck-Boost Converter

Recently the blushless DC motor (BLDCM) has been quickly developed. It has not only the same good characteristics of speed control as traditional DC motor, but also some virtues of AC motors. But the problem of torque ripple prohibits its further use in accurate servo systems, so the research of eliminate the torque ripple have useful performance in practice.First, this paper has researched in the principle of torque ripple in BLDCM. The torque ripple caused by several probably reasons is analyzed in this paper, and the ways of eliminating these ripple are reviewed. A new method for reducing the torque ripple in brushless dc motors with a single current sensor has been proposed by adding the Buck-Boost converter that regulates the amplitude of the current. The proposed control scheme makes the commutation current slopes of incoming and outgoing phases balanced effectively during the commutation interval of the phase currents. So in such drives, torque ripple suppression technique is theoretically effective in commutation region as well as conduction region.Second, based on studying the principle of Buck-Boost converter, compared the methods of different controlled modes, then a new method been proposed by technique-multi-loop control. This method has improved the performance of the converter. Effectiveness and feasibility of the proposed control method is verified by experiments of matlab. So, it has based for the next work, with the combination of BLDCM.Third, in this paper analyzing the traditional control method of PWM model, indicating the influence of the torque ripple at the conduction region and the commutation region by mathematics formula deduce, supporting the new control method effectively.At last, through research the mathematics mode of BLDCM, used the SimPowerSystem block toolbox in the matlab/simulink software, established the motor block, the current control block, hall effect signals sensor block and the inverter block, simulating the whole BLDCM system. With analyzing the result of simulation, effectively proved the new method based on adding the Buck-Boost converter that regulates the amplitude of the current. It has given the new way of control BLDCM in practice.