Abstract: A power conversion device includes a harmonic voltage generation unit that superimposes dc-axis and qc-axis harmonic voltages on dc-axis and qc-axis voltage commands in accordance with a switching signal; and an inductance estimation unit that estimates dc-axis inductance and qc-axis inductance on a basis of dc-axis and qc-axis harmonic currents, amplitude values of the harmonic voltages, and the switching signal.

Abstract: A power conversion apparatus controls a load apparatus by position sensorless vector control. The power conversion apparatus includes: a current detection unit configured to detect a current passing through the load apparatus; a current detection arithmetic unit configured to calculate a harmonic current component on a dc-axis as a control axis and a harmonic current component on a qc-axis, based on the detected current; a saliency ratio estimation unit configured to output a saliency ratio estimated value based on the harmonic current component on the dc-axis and the harmonic current component on the qc-axis; and a saliency ratio control unit configured to output a current component that increases or decreases a current command value on a d-axis of a rotor coordinate system, based on a deviation between the saliency ratio estimated value and a predetermined saliency ratio.

Abstract: This power conversion device has: a current measurement unit for measuring phase current; a current vector calculation unit for calculating a current vector by performing 3-phase to 2-phase conversion on the phase current; an amount-to-be-analyzed calculation unit for calculating, on the basis of the current vector, an amount to be analyzed; and a feature amount waveform extraction unit for extracting a waveform in a specific frequency range on the basis of the amount to be analyzed.

Abstract: An object of the present invention is to provide an electric power steering apparatus capable of improving reliability of a drive device for a three-phase synchronous motor without increasing a cost of the drive device. A control device for controlling an electric power steering apparatus according to the present invention is a control device for controlling an electric power steering apparatus using a three-phase synchronous motor as a force assisting in a steering operation, includes: a rotational position estimation unit that estimates a position of a rotor of the three-phase synchronous motor on the basis of a neutral point potential or a virtual neutral point potential of the three-phase synchronous motor; and a command signal computing unit that computes a command signal to the three-phase synchronous motor on the basis of the position of the rotor estimated by the rotational position estimation unit.

Abstract: An induction motor overheat monitoring method and device detects overheating of an induction motor from a detection value of a current sensor. A resistance calculation relationship data indicating a relationship between a resistance and a feature amount at the time of starting of the induction motor and a determination reference value for determining overheating are stored in advance. At each starting, a current of the induction motor is detected, a signal regarding a phase angle difference is calculated, and a feature amount of the motor is calculated from the signal regarding the phase angle difference. Further, a resistance of the induction motor is calculated by using the feature amount of the motor and the resistance calculation reference data stored in advance. Then, a temperature of the induction motor is calculated from the resistance of the induction motor, and it is determined if the motor is overheated.

Abstract: Provided is an AC electric motor control device capable of detecting, in an AC electric motor drive device, abnormal operation of an AC electric motor or abnormal operation due to, for example, a sudden change of a load without an erroneous operation regardless of the operational state of the AC electric motor. When driving a three-phase AC electric motor by an inverter, inside a controller, an electric motor constant is calculated using at least one of the current, voltage, and rotational speed of the electric motor and the variation of the constant value is analyzed, thereby detecting abnormal operation of the electric motor or abnormal operation of a load device connected to the electric motor. In order to analyze the constant, a variation to be determined to be abnormal is preset or an abnormal value is calculated in comparison with the accumulated values of past constant changes. Alternatively, only the variation of the constant calculated in the controller is extracted to detect abnormality.

Abstract: A rotating machine drive system includes: a rotating machine that includes a plurality of windings; a phase current detecting circuit that detects a phase current to be supplied to the rotating machine; an inverter device that includes an inverter circuit that converts DC power from a DC power supply into AC power, and a control device that controls power conversion being performed by an inverter main circuit on the basis of the phase current detected by the phase current detecting circuit, the inverter device operating the rotating machine at a variable speed; and a winding switching device that switches connections of the plurality of windings in accordance with a command from the control device.

Abstract: An object of the present invention is to provide a technique for monitoring the condition of a device or a target processing object. A monitoring system according to one aspect of the present invention monitors a device powered by an AC motor and estimates a condition of at least one of the device or a target processing object of the device, and includes a time-series data acquisition unit configured to acquire voltage data relating to a drive voltage of an AC motor; a feature value computation unit configured to analyze a feature value of an abnormal voltage waveform in a time-series waveform of the voltage data; and a state estimation unit configured to estimate the condition based on the feature value of the abnormal voltage waveform.

Abstract: In a motor drive device 120, a phase compensation amount calculation unit 110 calculates a phase compensation amount ?? for compensating a voltage phase ?v* when a control mode is switched in a control selection unit 90. The control selection unit 90 outputs the three-phase voltage command Vuvw* according to any one of the plurality of control modes based on the modulation factor Kh*, the voltage phase ?v*, and the phase compensation amount ??. A PWM control unit 100 outputs gate signals Gun, Gup, Gvn, Gvp, Gwn, and Gwv based on the three-phase voltage command Vuvw* and a rotor position ?d. The inverter 20 has a plurality of switching elements, and controls the plurality of switching elements based on gate signals Gun, Gup, Gvn, Gyp, Gwn, and Gwv to drive the AC motor 10.

Abstract: A power conversion device according to the present invention is connected to a rotating machine comprising an armature coil and supplies and receives power. The power conversion device has a function for: collectively applying voltage pulses to the armature coil or coils for one or more specific phases of the rotating machine, sampling the current values of the specific phases from the start of the rising or falling of the voltage pulses until a designated delay time, detecting variation in the capacitance of an insulation member of the armature coils of the specific phases of the rotating machine from variation from a normal state of the current values, and diagnosing insulation degradation.

Abstract: Provided is an AC electric motor control device capable of detecting, in an AC electric motor drive device, abnormal operation of an AC electric motor or abnormal operation due to, for example, a sudden change of a load without an erroneous operation regardless of the operational state of the AC electric motor. When driving a three-phase AC electric motor by an inverter, inside a controller, an electric motor constant is calculated using at least one of the current, voltage, and rotational speed of the electric motor and the variation of the constant value is analyzed, thereby detecting abnormal operation of the electric motor or abnormal operation of a load device connected to the electric motor. In order to analyze the constant, a variation to be determined to be abnormal is preset or an abnormal value is calculated in comparison with the accumulated values of past constant changes. Alternatively, only the variation of the constant calculated in the controller is extracted to detect abnormality.

Abstract: To enable overmodulation control having high controllability and low noise characteristics, a control device of an AC motor includes an inverter for driving an AC motor and a controller for controlling the inverter by pulse width modulation. The controller, when over-modulating the inverter, limits the amplitude of the voltage command in the pulse width modulation to a predetermined upper limit value or less.

Abstract: A power conversion device includes a harmonic voltage generation unit that superimposes dc-axis and qc-axis harmonic voltages on dc-axis and qc-axis voltage commands in accordance with a switching signal; and an inductance estimation unit that estimates dc-axis inductance and qc-axis inductance on a basis of dc-axis and qc-axis harmonic currents, amplitude values of the harmonic voltages, and the switching signal.

Abstract: A power conversion apparatus controls a load apparatus by position sensorless vector control. The power conversion apparatus includes: a current detection unit configured to detect a current passing through the load apparatus; a current detection arithmetic unit configured to calculate a harmonic current component on a dc-axis as a control axis and a harmonic current component on a qc-axis, based on the detected current; a saliency ratio estimation unit configured to output a saliency ratio estimated value based on the harmonic current component on the dc-axis and the harmonic current component on the qc-axis; and a saliency ratio control unit configured to output a current component that increases or decreases a current command value on a d-axis of a rotor coordinate system, based on a deviation between the saliency ratio estimated value and a predetermined saliency ratio.

Abstract: An induction motor overheat monitoring method and device detects overheating of an induction motor from a detection value of a current sensor. A resistance calculation relationship data indicating a relationship between a resistance and a feature amount at the time of starting of the induction motor and a determination reference value for determining overheating are stored in advance. At each starting, a current of the induction motor is detected, a signal regarding a phase angle difference is calculated, and a feature amount of the motor is calculated from the signal regarding the phase angle difference. Further, a resistance of the induction motor is calculated by using the feature amount of the motor and the resistance calculation reference data stored in advance. Then, a temperature of the induction motor is calculated from the resistance of the induction motor, and it is determined if the motor is overheated.

Abstract: A power conversion device according to the present invention is connected to a rotating machine comprising an armature coil and supplies and receives power. The power conversion device has a function for: collectively applying voltage pulses to the armature coil or coils for one or more specific phases of the rotating machine, sampling the current values of the specific phases from the start of the rising or falling of the voltage pulses until a designated delay time, detecting variation in the capacitance of an insulation member of the armature coils of the specific phases of the rotating machine from variation from a normal state of the current values, and diagnosing insulation degradation.

Abstract: A rotating machine drive system includes: a rotating machine that includes a plurality of windings; a phase current detecting circuit that detects a phase current to be supplied to the rotating machine; an inverter device that includes an inverter circuit that converts DC power from a DC power supply into AC power, and a control device that controls power conversion being performed by an inverter main circuit on the basis of the phase current detected by the phase current detecting circuit, the inverter device operating the rotating machine at a variable speed; and a winding switching device that switches connections of the plurality of windings in accordance with a command from the control device.

Abstract: According to the present invention, in position sensorless control for switching between a 120-degree energization scheme for a low-speed region and a 180-degree energization scheme for a mid-to-high-speed region, stable and highly accurate speed control characteristics are provided by suppressing speed deviation ??r in the low-speed region, and by preventing current jump-up caused by a discontinuous rotational speed occurring during switching to the mid-to-high-speed region. In the case of driving in the 120-degree energization scheme, a voltage command value is corrected such that an estimated speed value or a detected speed value follows a speed command.

Abstract: In a motor drive device 120, a phase compensation amount calculation unit 110 calculates a phase compensation amount ?? for compensating a voltage phase ?v* when a control mode is switched in a control selection unit 90. The control selection unit 90 outputs the three-phase voltage command Vuvw* according to any one of the plurality of control modes based on the modulation factor Kh*, the voltage phase ?v*, and the phase compensation amount ??. A PWM control unit 100 outputs gate signals Gun, Gup, Gvn, Gvp, Gwn, and Gwv based on the three-phase voltage command Vuvw* and a rotor position ?d. The inverter 20 has a plurality of switching elements, and controls the plurality of switching elements based on gate signals Gun, Gup, Gvn, Gyp, Gwn, and Gwv to drive the AC motor 10.

Abstract: A highly reliable electromechanical integral motor is provided. In the electromechanical integral motor including an axial gap type motor and a power conversion control device, the power conversion control device is mounted on an end bracket portion of the motor. Additionally, a space is provided between the end bracket portion of the motor and the power conversion control device. Further, the end bracket portion of the motor and the power conversion control device are fixed by a plurality of fixing members, and at least one set of the plurality of fixing members is disposed to be spaced apart from each other.