A simple equivalent circuit for efficiency calculation of brushless DC motors

This paper shows the calculation method of several loses and motor efficiency using the simple equivalent circuit, in which copper loss, eddy current loss, hysteresis loss, friction loss and viscous loss, and inverter loss are taken into account. We clarify each loss of the brushless DC motor and motor efficiency at different motor speeds and different output torques using the Microsoft-Excel. Moreover, the simulation results have a good agreement with the measured ones.