Abstract: A motor driving apparatus includes a rectifying circuit to rectify an AC power supplied from an external AC power source, one pair of film capacitors to output a DC voltage and a neutral point voltage by removing a ripple of a voltage rectified by the AC-DC conversion unit, a 3-level inverter to supply a driving current to a motor using the DC voltage applied from the DC link unit, and a control module to control the 3-level inverter. The control module includes a motor speed control module to control the rotation of the motor, a DC voltage control module to stabilize the DC voltage, a neutral point voltage control module to stabilize the neutral point voltage, and a stabilizing voltage limiting module to control the DC voltage control module and the neutral point voltage control module according to an output of the motor speed control module.

Abstract: A motor includes a stator and a rotor that is arranged opposite to the stator through a predetermined air gap. The stator is such that a plurality of coils are wound around respective slots for each of a plurality of phases. In the stator, the number of turns of one of the plurality of coils is different from those of the others for each of the phases. In the rotor, among a plurality of magnetic poles formed of a plurality of permanent magnets arranged in a circumferential direction of a core, a magnetoresistance of at least one magnetic pole is different from those of the others.

Abstract: A single external power supply variable speed induction motor and a control method thereof are disclosed. An induction motor includes: a stator in which coils directly connected to a single-phase or 3-phase or more systematic power supply are wound; a rotor that is supported to be rotatable in the stator; a power conversion device that is attached to the rotor and controls a rotor current without connection of a separate external power supply; and a control circuit that is connected to the power conversion device and controls the power conversion device.

Abstract: An inverter control apparatus and a control method thereof are provided. The inverter control apparatus and a control method thereof stably operate a three-phase motor using a capacitor having a small capacitance for a DC link. The inverter control apparatus includes a current sensor to sense an output current of the inverter, a voltage sensor to sense a DC-link voltage of the inverter, and a controller to generate an average of a periodically varying rotor based q-axis current boundary value based on the output current and the DC-link voltage to generate a current reference on the basis of the average of the rotor based q-axis current boundary value, and to drive a three-phase motor based on the current reference. Stabilized variable speed control of a motor by using a small-capacitance capacitor for a DC link of an inverter is performed and reliability of an inverter circuit improved.

Abstract: A three-level inverter having two direct current (DC)-links for converting DC voltages generated in a plurality of photovoltaic (PV) modules into alternating current (AC) voltages, wherein one end of a first DC-link of the two DC-links is connected to a first potential point at which a first potential is generated in the plurality of PV modules, and one end of a second DC-link of the two DC-links is connected to a second potential point at which a second potential that is lower than the first potential is generated in the plurality of PV modules, and both the other end of the first DC-link and the other end of the second DC-link are connected to a third potential point at which a third potential having a medium level between the first potential and the second potential is generated in the plurality of PV modules.

Abstract: An inverter control apparatus and a control method thereof are provided. The inverter control apparatus and a control method thereof stably operate a three-phase motor using a capacitor having a small capacitance for a DC link. The inverter control apparatus includes a current sensor to sense an output current of the inverter, a voltage sensor to sense a DC-link voltage of the inverter, and a controller to generate an average of a periodically varying rotor based q-axis current boundary value based on the output current and the DC-link voltage to generate a current reference on the basis of the average of the rotor based q-axis current boundary value, and to drive a three-phase motor based on the current reference. Stabilized variable speed control of a motor by using a small-capacitance capacitor for a DC link of an inverter is performed and reliability of an inverter circuit improved.

Abstract: A winding synchronous machine having a moving object including an inverter circuit comprises: a moving-object inverter circuit connected to the moving object of the winding synchronous machine; and a moving-object circuit control device connected to the moving-object inverter circuit so as to control the moving-object inverter circuit. The moving-object circuit control device may comprise: a stator inverter voltage estimator estimating a high-frequency voltage of a stator inverter circuit; a field current reference generator generating a field current reference of the moving object; and an energy storage device voltage controller generating a current reference tracking a DC-link energy storage device voltage of the moving object. Problems associated with using a rare-earth permanent magnet can be thereby overcome, and a winding synchronous machine including an excitation circuit in which ripples almost never occur can be implemented without using an extra power source.

Abstract: A method of driving an alternating-current (AC) motor while periodically obtaining a rotator angle of the AC motor. The method includes: (a) driving the AC motor by a dS-axis voltage, which is a voltage for an exciting current in a stationary reference frame, and a qS-axis voltage, which is a voltage for generating a rotational force in the stationary reference frame, while sequentially applying different dS-axis voltages and different qS-axis voltages to the AC motor in a control injection period; and (b) obtaining a rotator angle by a dS-axis voltage value, a qS-axis voltage value, a dS-axis current value, and a qS-axis current value in the control injection period.

Abstract: A method of estimating inductance of a permanent magnet synchronous motor (PMSM) includes injecting a signal having a frequency differing from an operating frequency of the PMSM into the PMSM during sensorless operation, sensing magnitudes of current responses to the injected signal, and estimating an inductance value at which the magnitude of the sensed current response is minimal to be an actual inductance value of the PMSM, thereby estimating inductance used in the PMSM regardless of position estimation error of the PMSM and thus more accurately and reliably estimating inductance of the PMSM.

Abstract: A three-level inverter having two direct current (DC)-links for converting DC voltages generated in a plurality of photovoltaic (PV) modules into alternating current (AC) voltages, wherein one end of a first DC-link of the two DC-links is connected to a first potential point at which a first potential is generated in the plurality of PV modules, and one end of a second DC-link of the two DC-links is connected to a second potential point at which a second potential that is lower than the first potential is generated in the plurality of PV modules, and both the other end of the first DC-link and the other end of the second DC-link are connected to a third potential point at which a third potential having a medium level between the first potential and the second potential is generated in the plurality of PV modules.

Abstract: The present invention relates to a winding synchronous machine having a moving object including an inverter circuit, wherein a winding synchronous machine, including a winding synchronous motor or generator having a moving object including an inverter circuit, is provided, the winding synchronous machine being characterized by comprising: a moving-object inverter circuit connected to the moving object of the winding synchronous machine; and a moving-object circuit control device connected to the moving-object inverter circuit so as to control the moving-object inverter circuit.

Abstract: An inverter control apparatus and a control method thereof are provided. The inverter control apparatus and a control method thereof stably operate a three-phase motor using a capacitor having a small capacitance for a DC link. The inverter control apparatus includes a current sensor to sense an output current of the inverter, a voltage sensor to sense a DC-link voltage of the inverter, and a controller to generate an average of a periodically varying rotor based q-axis current boundary value based on the output current and the DC-link voltage to generate a current reference on the basis of the average of the rotor based q-axis current boundary value, and to drive a three-phase motor based on the current reference. Stabilized variable speed control of a motor by using a small-capacitance capacitor for a DC link of an inverter is performed and reliability of an inverter circuit improved.

Abstract: An alternating-current motor control apparatus includes an inverter unit, a current-command divider, a current controller, a torque-variation calculator, and a phase angle generator. The current-command divider is configured to divide a command current amplitude into command current components based on a phase-angle command value that is a sum of the phase angle and an alternating current signal. The torque-variation calculator is configured to calculate a motor electric power based on the command voltage and either the motor current or the command current components and to calculate a torque variation based on the motor electric power. The phase angle generator is configured to generate a phase angle based on the torque variation.

Abstract: A method of driving an alternating-current (AC) motor while periodically obtaining a rotator angle of the AC motor. The method includes: (a) driving the AC motor by a dS-axis voltage, which is a voltage for an exciting current in a stationary reference frame, and a qS-axis voltage, which is a voltage for generating a rotational force in the stationary reference frame, while sequentially applying different the dS-axis voltages and different qS-axis voltages to the AC motor in a control injection period; and (b) obtaining a rotator angle by a dS-axis voltage value, a qS-axis voltage value, a dS-axis current value, and a qS-axis current value in the control injection period.

Abstract: A single external power supply variable speed induction motor and a control method thereof are disclosed. An induction motor includes: a stator in which coils directly connected to a single-phase or 3-phase or more systematic power supply are wound; a rotor that is supported to be rotatable in the stator; a power conversion device that is attached to the rotor and controls a rotor current without connection of a separate external power supply; and a control circuit that is connected to the power conversion device and controls the power conversion device.

Abstract: An alternating-current motor control apparatus includes a voltage controller configured to output a command voltage vector so that the command voltage vector is time-averaged for time periods, a square-wave voltage generator configured to control, every time period, amplitudes and phases of voltages to be applied to an alternating-current motor, a current detector configured to detect motor currents at a timing synchronized with periods 1/N-th of the time periods, where N is equal to or larger than one, a coordinate transformation section configured to perform coordinate transformation to transform the motor currents into two-phase currents, an envelope extractor configured to extract two-phase currents as waveforms having amplitudes that periodically change from the two-phase currents, and extract envelopes of the waveforms, and a magnetic-pole-position computing section configured to compute a magnetic-pole position using the envelopes.

Abstract: A method of estimating inductance of a permanent magnet synchronous motor (PMSM) includes injecting a signal having a frequency differing from an operating frequency of the PMSM into the PMSM during sensorless operation, sensing magnitudes of current responses to the injected signal, and estimating an inductance value at which the magnitude of the sensed current response is minimal to be an actual inductance value of the PMSM, thereby estimating inductance used in the PMSM regardless of position estimation error of the PMSM and thus more accurately and reliably estimating inductance of the PMSM.

Abstract: An alternating-current motor control apparatus includes an inverter unit, a current-command divider, a current controller, a torque-variation calculator, and a phase angle generator. The inverter unit is configured to output a command voltage to an alternating-current motor. The current-command divider is configured to divide a command current amplitude into command current components based on a phase-angle command value that is a sum of the phase angle and an alternating current signal. The current controller is configured to control current to match a motor current flowing through the motor with the command current components. The torque-variation calculator is configured to calculate a motor electric power based on the command voltage and either the motor current or the command current components and to calculate a torque variation based on the motor electric power. The phase angle generator is configured to generate a phase angle based on the torque variation.

Abstract: Methods and systems are provided for controlling an AC motor via an inverter. The method includes determining a delay-compensated offset based on a synchronous frame current, producing a current error based on a synchronous frame current and a commanded current, producing a voltage error based on an anti-windup offset and the current error, producing a commanded voltage based on the delay-compensated offset and the voltage error, and providing the inverter with the commanded voltage.

Abstract: An alternating-current motor control apparatus includes a voltage controller configured to output a command voltage vector so that the command voltage vector is time-averaged for time periods, a square-wave voltage generator configured to control, every time period, amplitudes and phases of voltages to be applied to an alternating-current motor, a current detector configured to detect motor currents at a timing synchronized with periods 1/N-th of the time periods, where N is equal to or larger than one, a coordinate transformation section configured to perform coordinate transformation to transform the motor currents into two-phase currents, an envelope extractor configured to extract two-phase currents as waveforms having amplitudes that periodically change from the two-phase currents, and extract envelopes of the waveforms, and a magnetic-pole-position computing section configured to compute a magnetic-pole position using the envelopes.