Effects of Core Materials and Operating Parameters on Core Losses in a Brushless DC Motor

Abstract

The development of high-efficiency DC motors is a very important technique subject from the viewpoint of energy saving. In order to increase the motor efficiency, three different grades of electrical steel laminations are used to design a brushless DC (BLDC) motor in the paper since they provide reduced core losses. A measurement of core losses of three different grades of electrical steel laminations in Epstein Frame is implemented to determine the WT-Bmax core loss curves under sinusoidal waveform step by step from 60 Hz to 5000Hz. The core losses in a BLDC motor fed by a PWM control DC Square-Wave voltage supply are estimated using the WT-Bmax core loss curves. The effects of three core materials on the core losses of the BLDC motor have been studied in the paper. The computed core losses are compared to those evaluated by using a 2D finite element analysis. The effects of various operating conditions on the core losses in the BLDC motor laminations are also investigated in this paper. The presented results give guidelines to the selection of core materials and the operating points to improve motor efficiency.