Abstract: An apparatus and method determine a start-up of a sensorless motor. The apparatus includes an elapsed time determination unit, a motor velocity determination unit and an abnormal start-up determination unit. The elapsed time determination unit determines whether a predetermined time has elapsed after a start-up of the motor is initiated. The motor velocity determination unit determines whether a velocity of the motor exceeds a predetermined velocity value when the predetermined time has elapsed. The abnormal start-up determination unit determines that the motor was abnormally started up when the velocity of the motor does not exceed the predetermined value, and an amount of current flowing in the motor does not exceed a predetermined current value.

Abstract: A PMA (Permanent Magnet Assisted) synRM and a method for imposing a magnetic force thereon. Magnets are inserted into outer flux barriers of a plurality of flux barriers formed along the radius of a rotor, and bridges or slim portions are formed on inner flux barriers at positions corresponding to the positions of the magnets so that the magnetic force is imposed on the magnets through coils. Since the number of the flux barriers is sufficiently increased while the amount of the magnets consumed is decreased, the PMA synRM has increased efficiency and reduced production costs.

Abstract: A sensorless motor drive apparatus and a method for protecting and controlling the same. The sensorless motor drive apparatus includes a unit for determining the presence or absence of a position estimation error of a rotor contained in a motor using a current value applied to the motor and a position estimation angle of the rotor. Therefore, the sensorless motor drive apparatus determines the presence or absence of the position estimation error of the rotor without using a sensor, so that it reduces production costs, prevents the motor from generating a faulty operation, and prevents a compressor including the motor from being damaged.