I. Introduction
BLDC motors are widely used in the applications, such as robotics and automation, aerospace, electric vehicles, manufacturing and military drive systems [1] although in a few applications brushed DC motors are tolerable choice [2]–[4]. BLDC motors are composed of a rotor containing permanent magnets and the armature, which remains motionless (Fig. 1). The motor is controlled by an electronically controlled commutation system instead of a mechanical commutation system. BLDC motors have advantages over brushed DC motors, such as higher reliability, longer lifetime and higher efficiency [5].
BLDC motor construction [6]