Abstract: A motor braking unit for a washing machine that offers high braking efficiency while preventing overcharging a capacitor in a DC link. The motor braking unit determines a current to be supplied to the motor based on a detected speed of the motor. The motor braking unit dynamically monitors the voltage on the capacitor against a reference voltage. If the capacitor voltage is lower than the reference voltage, the current component Iq is increased to increase the braking torque; and if the capacitor voltage is greater than the reference voltage, the current Iq component is decreased to prevent overcharging on the capacitor by the motor.

Abstract: A method and an apparatus for detecting a laundry weight of a washing machine can correctly detect a laundry weight of a washing machine. To this end, a motor of a washing machine is driven at a first speed and then at a second speed, and a laundry weight is detected on the basis of a value of a first current for driving the motor at the first speed and a value of a second current for driving the motor at the second speed.

Abstract: An apparatus and method for determining the presence or absence in a motor lock error in a sensorless motor. The method includes the steps of: driving the sensorless motor; determining whether or not a predetermined time elapses after the sensorless motor has been driven; measuring a current applied to the sensorless motor after the lapse of the predetermined time; calculating a difference between the measured current with a predetermined reference current; and determining the presence or absence of a motor lock error in the sensorless motor by determining whether the determined difference is equal to or higher than a predetermined reference difference, so that it quickly determines the presence or absence of a motor lock error in the sensorless motor without using a sensor and prevents an overcurrent from flowing in the sensorless motor, resulting in the prevention of a faulty operation or damage to the sensorless motor.

Abstract: An electric motor includes: a stator having a plurality of first coils with a rotor receiving part formed inside thereof and generating a rotating magnetic field and a plurality of second coils making a pair with the first coils and generating an induction magnetic field induced by the magnetic field of the first coils; a first rotor formed as a hollow permanent magnet, installed in the rotor receiving part and rotated by the magnetic field formed in the first coils and the second coils of the stator; and a second rotor having a rotational shaft fixedly installed at a center of the second rotor, and being installed inside the first rotor so as to be rotated by rotation of the first rotor.

Abstract: A method and an apparatus for detecting a laundry weight of a washing machine can correctly detect a laundry weight of a washing machine. To this end, a motor of a washing machine is driven at a first speed and then at a second speed, and a laundry weight is detected on the basis of a value of a first current for driving the motor at the first speed and a value of a second current for driving the motor at the second speed.

Abstract: An electric motor, more particularly, a rotor structure of an electric motor comprises: a stator including a plurality of teeth and coil wound on the teeth to form rotary magnetic flux by applied electric source; a rotary shaft; and a rotor rotatably installed in the stator, the rotor including a shaft insertion hole so that the rotary shaft can be inserted therethrough and fixed, wherein, the rotor includes a plurality of permanent magnet insertion slots of ‘V’ or ‘U’ shape formed in radial direction as centering around the shaft insertion hole, and permanent magnets are inserted and fixed into the permanent magnet insertion slots respectively, and a plurality of air gap expanding portions, on which air gaps from the teeth of the stator are expanded, are formed on an outer circumferential surface of the rotor.

Abstract: An electric motor includes: a stator having a plurality of first coils with a rotor receiving part formed inside thereof and generating a rotating magnetic field and a plurality of second coils making a pair with the first coils and generating an induction magnetic field induced by the magnetic field of the first coils; a first rotor formed as a hollow permanent magnet, installed in the rotor receiving part and rotated by the magnetic field formed in the first coils and the second coils of the stator; and a second rotor having a rotational shaft fixedly installed at a center of the second rotor, and being installed inside the first rotor so as to be rotated by rotation of the first rotor.

Abstract: An electric motor, more particularly, a rotor structure of an electric motor comprises: a stator including a plurality of teeth and coil wound on the teeth to form rotary magnetic flux by applied electric source; a rotary shaft; and a rotor rotatably installed in the stator, the rotor including a shaft insertion hole so that the rotary shaft can be inserted therethrough and fixed, wherein, the rotor includes a plurality of permanent magnet insertion slots of ‘V’ or ‘U’ shape formed in radial direction as centering around the shaft insertion hole, and permanent magnets are inserted and fixed into the permanent magnet insertion slots respectively, and a plurality of air gap expanding portions, on which air gaps from the teeth of the stator are expanded, are formed on an outer circumferential surface of the rotor.

Abstract: An apparatus for sensing a laundry amount in a washing machine includes: a rectifier; an inverter receiving a DC voltage and converting it to a three-phase AC voltage, a BLDC motor driven by the three-phase AC voltage from the inverter, a rotor position detector detecting the position of a rotor of the BLDC motor; a microcomputer outputting a control signal for controlling a switching operation of the inverter according to the position detect signal of the rotor position detector and a current control signal; a gate driving unit receiving the control signal from the microcomputer and outputting a gate drive signal to the inverter; a torque command generator generating a torque command signal corresponding to a speed set by a user; a torque controller operating the torque command signal from the torque command generator and outputting a q-axis current command signal; a current controller outputting the current control signal according to the q-axis current command signal from the torque controller and a d-axis

Abstract: An apparatus for detecting a rotor position in a brushless direct current (BLDC) motor, in which a rotor position can be detected by a virtual neutral point voltage and current of one phase in a motor. The number of circuits required for the rotor position detection is reduced to save the production cost and reduce the space occupied by a position detecting circuit.

Abstract: An apparatus for sensing a laundry amount in a washing machine includes: a rectifier; an inverter receiving a DC voltage and converting it to a three-phase AC voltage, a BLDC motor driven by the three-phase AC voltage from the inverter, a rotor position detector detecting the position of a rotor of the BLDC motor; a microcomputer outputting a control signal for controlling a switching operation of the inverter according to the position detect signal of the rotor position detector and a current control signal; a gate driving unit receiving the control signal from the microcomputer and outputting a gate drive signal to the inverter; a torque command generator generating a torque command signal corresponding to a speed set by a user; a torque controller operating the torque command signal from the torque command generator and outputting a q-axis current command signal; a current controller outputting the current control signal according to the q-axis current command signal from the torque controller and a d-axis