Measurement of BLDC Motor Efficiency for Commutation Angle Optimisation

Abstract

This paper describes an approach for measuring efficiency of BLDC motor fan for different commutation angles. Such measurement is needed for commutation angle optimisation. Experimental measurement shows that fan speed fluctuates around the long time average value. Therefore, the statistical approach is used to define the number of samples in moving average calculation of efficiency for selected confidence interval. In most cases, the commutation angles are derived from the fixed position Hall sensor. Presented measurement shows that efficiency is a continuous function of several angle parameters with the global maximum. Commutation angle of this global maximum does not match the Hall sensor signal exactly. Hence, simple gradient optimisation method can be used to find optimal commutation angles for the highest efficiency.