Small copper loss unidirectional energized BLDC motor and the motor system

Abstract

Unidirectional energized Brushless DC (BLDC) motor can be adopted in a small motor system. Minato motor is one of the unidirectional energized BLDC motors. Recently, bidirectional energized BLDC motor is being mainly studied. However, controlling the direction of the torque by each armature winding for unidirectional motor system is easier. Therefore, the authors developed a high efficient unidirectional energized BLDC motor. Asymmetric H-bridge circuit is used as a driver circuit for the proposed motor. This circuit is hard to break down, compared to the inverter used in bidirectional energized BLDC motor. During high speed rotation, undesirable armature current, which has deceleration characteristic, is generated. This current lowers the efficiency of motor. In this paper, the authors proposed measures for this solution in the proposed motors. The authors show the proof through the equations of copper loss ratio for Minato motor and proposed motors. The “3rd motor” which has the highest efficiency was discovered during examination of the equations.