Kabushiki Kaisha Yaskawa Denki

Shingo Fukumaru

Shinya Morimoto

Akira Yamazaki

Hideaki Iura

Hirofumi Kinomura

Keita Shimamoto

Kentaro Inomata

Takahiro Saeki

Joji Ebisu

Takanori Iwaki

To provide a power conversion device that is effective for improving controllability of power in power conversion for multilevel voltage output. A power conversion device includes a switching circuit configured to supply a current to a motor by connecting and disconnecting a first point having a first potential, a second point having a second potential greater than the first potential, and a neutral point having a neutral potential between the first potential and the second potential to and from the motor, a neutral potential control unit configured to control the switching circuit in a manner to maintain the neutral potential within a target range, and a current control unit configured to increase a supply current to the motor without affecting a driving force generated by the motor at least when controlling the switching circuitby the neutral potential control unit.

Power conversion device and power conversion method

A control device which includes a power conversion circuit configured to supply driving power to an electric motor, a magnetic flux estimation circuit configured to estimate a primary magnetic flux of the motor, and a voltage command generation circuit (control circuit) configured to control the conversion circuit based on an estimation result of the primary magnetic flux, in which the estimation circuit performs, when an operating speed of the motor is less than a predetermined level, a first estimation of estimating the primary magnetic flux based on an output current to the motor and an inductance thereof, and performs, when the speed exceeds a predetermined level, a second estimation of estimating the primary magnetic flux by estimating a magnetic flux differential value based on an output voltage of the conversion circuit and integrating the value using, as an initial value, an estimation result by the first estimation.

Control device, magnetic flux estimation device, and magnetic flux estimation method

A power conversion apparatus includes a power converter circuit that outputs an AC power to an electric motor, and circuitry that controls the power converter circuit to add a first change, accompanying a change of a power generated by the electric motor, to a first phase angle, which is a phase angle of a magnetic flux direction of the electric motor corresponding to the AC power, extracts a component generated by the first change from first information indicating the electric power supplied to the electric motor, and estimates the power generated by the electric motor based on the component.

Power conversion apparatus, power estimating method for electric motor, and control method for electric motor

A power conversion apparatus includes: a power converter that includes a plurality of switching elements; and a controller that controls the plurality of switching elements. The controller includes: a command generator that generates a voltage command vector; a synthesizer that synthesizes a correction vector with the voltage command vector to generate a synthetic vector; an adjuster that adjusts an output time of a plurality of voltage vectors from the power converter, the output time being corresponding to the synthetic vector; and a correction vector generator that generates the correction vector on the basis of an adjustment result of the adjuster.

Power conversion apparatus, control apparatus, and control method using a correction vector

A rotation controller for an AC electric motor includes a space vector generator, a current change ratio obtainer, and a rotational angle calculator. The space vector generator generates at least a first magnetic field in a first direction and a second magnetic field in a second direction crossing the first direction in a rotation plane of a saliency-exhibiting rotor. The space vector generator synthesizes the first magnetic field and the second magnetic field into a synthesized magnetic field. The current change ratio obtainer acquires a first current change ratio of a first current generated in the first direction in a stator and a second current change ratio of a second current generated in the second direction in the stator. The rotational angle calculator calculates a rotational angle of the saliency-exhibiting rotor based on at least the first and second current change ratios and the first and second directions.

Rotation controller for AC electric motor and method for controlling rotation of the AC electric motor

A power conversion apparatus includes: a power converter that includes a plurality of switching elements; a switch controller that controls the plurality of switching elements so that the order of outputting a plurality of kinds of voltage vectors from the power converter is opposite in a first half and a latter half of a carrier period; a DC-side current detector that detects a DC-side current of the power converter; and a phase current detector that detects one phase current among three phase currents on the basis of the detected DC-side current at a detection timing, the detection timing being selected from a first-half timing and a latter-half timing of the carrier period at which the same kind of voltage vector is output. The phase current detector includes a timing switcher that alternately switches the detection timing between the first-half timing and the latter-half timing.

Power conversion apparatus, phase current detection apparatus, and phase current detection method

A motor control device is provided, which includes a power converter for applying output voltage according to a voltage command to an electric motor, a magnetic flux estimator for estimating a vector of stator magnetic flux of the electric motor based on a difference between the output voltage and a voltage drop caused by a coil resistance of the electric motor, and a phase estimator for estimating a phase of the stator magnetic flux based on the vector of the stator magnetic flux estimated by the magnetic flux estimator. The magnetic flux estimator includes a variable low-pass filter for applying a low-pass filter to the difference at a cut-off frequency according to a frequency of the output voltage, and a phase adjuster for retarding at least one of an output phase of the variable low-pass filter and a phase of the difference before inputted into the variable low-pass filter.

Motor control device, and method and device for estimating magnetic flux of electric motor

A motor control apparatus according to the embodiment includes a rotational position estimating unit, a change amount estimating unit, and an inductance estimating unit. The rotational position estimating unit estimates a rotational position of a rotor from a motor parameter including a q-axis inductance of a motor on a basis of an output current to the motor and a voltage reference. The change amount estimating unit estimates a change amount of an output torque with respect to a current phase change of the motor corresponding to a high frequency signal whose frequency is higher than a drive frequency of the motor. The inductance estimating unit estimates an inductance value that obtains a maximum torque on a basis of the change amount as the q-axis inductance.

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Kitakyushu, Japan

Shingo Fukumaru