A Torque Ripple Compensation Technique for a Low-Cost Brushless DC Motor Drive

This paper presents a torque ripple compensation technique for a brushless dc (BLDC) motor drive that is operated without a DC link capacitor. The motor drive, which uses a single-switch control strategy, resembles that of a buck converter during operation at any switching state. A simple buck-converter-based model is therefore proposed to predict the behavior of the BLDC motor drive at constant speed. Using the model, the impact of operation without the DC link capacitor on the torque produced by the BLDC motor drive is investigated in detail. Theoretical behavior of the BLDC motor drive is compared with MATLAB/Simulink-based simulations to demonstrate the validity of the compensation technique and the analysis. Experimental results of a 250 W prototype motor drive are also presented to further validate the theoretical analysis, as well as the effectiveness of the proposed technique. Results convincingly indicate that the BLDC motor drive with torque ripple compensation offers comparable performance.