Comparative Non-Linear Flux Matrices and Thermal Losses in BLDC with Different Pole Pairs

In this paper, brushless DC motors are evaluated for nonlinear flux-linkages and thermal losses in the windings and rotor, which causes additional voltage drop and can lead to very dangerous symmetrical three phase line-line-line (LLL) short-circuit. In the paper, it is shown that if the motor does not have appropriate cooling mechanism or other protectionary switchgear, the temperatures in 8-pole (or higher poles) motor with continuous load reaches 1000◦ C, which is nearer to the melting point of copper winding. Thirteen BLDC motors with pole pairs varying from 1 to 13 are studied for comparison for the simulation of thermal losses. The resulting eleven outputs namely rotor angle matrices, flux linkages matrices, flux linkage partial derivatives with respect to current vector, rotor angle, per phase current, each phase winding temperatures, rotor temperature, have been collected as datasets. On knowing the estimated increase in temperature, manufacturers can decide appropriate insulation, cooling mechanism and other motor protectionary circuits.