실험계획법을 이용한 고속 회전 BLDC 모터의 냉각 시스템 최적화

Abstract

It is of great importance to decrease the maximum temperatures of electric motors as low as possible, particularly in motor coils in terms of durability and reliability issues. In this study, computational fluid dynamics (CFD) analysis were performed to figure out heat transfer phenomena in advanced brushless direct current motors (BLDCs). Various heat source terms by reversible and irreversible energy losses were modeled to demonstrate temperature distributions in computation domains of high speed BLDC motors under diverse operating conditions, followed by heat transfer analysis for the optimal designs of motor cooling pipes. Design of experiment (DOE) methods were adopted to find out the most efficient cooling pipe specifications such as pipe diameter, pipe thickness, the number of turns, and water flow rate through the pipe. Heat transfer rates in the radial direction through solid stators and in the axial direction through the central rotating shaft are compared to calculate heat collection rates by the cooling pipes. In addition, three-dimensional temperature distributions are presented to account for the effects of the geometric and operating parameters on the maximum temperatures of stator coils. Finally, the optimal design parameters of the cooling pipe systems are comprehensively determined by analyzing both maximum temperature of electrical motors and pressure drop in the motor cooling pipe.