Patent ID: 8089240

Claim:
A motor comprising: a rotor; a coil wound around a stator; a controller for controlling an input power of the coil to control a rotation of the rotor; a PWM calculator for receiving a signal of an uvw stationary coordinate system to generate a PWM signal; an inverter for receiving the PWM signal to directly the input power of the coil; a current detector for detecting a d-axis present current (Id) and a q-axis present current (Iq) of a d-q rotating coordinate system as a present current output from the inverter; a current controller for generating a d-axis reference voltage (Vd*) and a q-axis reference voltage (Vq*) on the d-q rotating coordinate system by referring to the present currents (Id, Iq) detected by the current detector, so as to follow a reference speed of the controller; and a coordinate transformer for transforming the d-q rotating coordinate system into the uvw stationary coordinate system and vice versa, wherein upon initial start of the motor, a reference current generated from the controller to generate a maximum motor torque greater than at least an external load torque is applied to the motor, and an amount of the reference current is gradually increased until the current reaches a predetermined current on at least one phase of the uvw stationary coordinate system, and the amount of the reference current is varied while an electrical angle is varied, so that the rotor is initially aligned in a specific region on the uvw stationary coordinate system.