Abstract: Provided is a power conversion device that converts power between DC units and three-phase AC. A first-phase conversion device, a second-phase conversion device, and a third-phase conversion device each include a DC/DC conversion circuit and a single-phase power conversion circuit. For each of the first-phase conversion device, the second-phase conversion device, and the third-phase conversion device, when an absolute value of a voltage target value for the AC exceeds DC voltage of each DC unit, a control unit causes the DC/DC conversion circuit to operate to achieve the absolute value of the voltage target value and causes the single-phase power conversion circuit to only perform necessary polarity inversion, and when the absolute value of the voltage target value is smaller than the DC voltage, the control unit stops operation of the DC/DC conversion circuit and causes the single-phase power conversion circuit to operate to achieve the voltage target value.

Abstract: This power conversion device includes: conversion devices for supplying AC powers to respective phases with respect to the neutral point of a three-phase AC system via reactors; and a control unit for controlling the conversion devices. Each conversion device includes: a step-up circuit for stepping up the DC input voltage value of DC power; and a single-phase inverter circuit.

Abstract: An inverter device includes: a step-up circuit; an inverter circuit; a control unit for controlling the step-up circuit and the inverter circuit; and a reactor provided on an electric path for outputting the converted AC power to an AC system. An output current target value is calculated based on an input power value of DC power and a voltage value of the AC system, and a current target value and a voltage target value for the inverter circuit are calculated based on the output current target value, to control the inverter circuit. A current target value for the step-up circuit is calculated based on a current target value and a voltage target value that are common with the inverter circuit, and on a DC input voltage value, to control the step-up circuit. Thereby, output of the AC power is controlled.

Abstract: A power conversion device includes: a conversion device for each phase which converts DC voltage inputted from a DC power supply, to voltage having an AC waveform to be outputted to each phase with respect to a neutral point of three-phase AC; and a control unit which controls these conversion devices. Each conversion device includes: a first conversion unit which has a DC/DC converter including an isolation transformer, and a capacitor, and which converts the inputted DC voltage to voltage containing a pulsating-current waveform corresponding to the absolute value of voltage obtained by superimposing a third-order harmonic on a fundamental wave as the AC waveform to be outputted; and a second conversion unit which has a full-bridge inverter for inverting the polarity of the voltage containing the pulsating-current waveform, per one cycle, thereby converting the voltage to voltage having the AC waveform.

Abstract: Provided is a power conversion device including: a conversion device for each phase which converts DC voltage inputted from a DC power supply, to voltage having an AC waveform to be outputted to each phase with respect to a neutral point of three-phase AC; and a control unit which controls these conversion devices. Each conversion device includes: a first converter which has a DC/DC converter including an isolation transformer, and a capacitor, and which converts the inputted DC voltage to voltage containing a pulsating DC voltage waveform corresponding to the absolute value of the AC waveform to be outputted; and a second converter which is provided at a stage subsequent to the first converter and has a full-bridge inverter, and which inverts the polarity of the voltage containing the pulsating DC voltage waveform, per one cycle, thereby converting the voltage to voltage having the AC waveform.

Abstract: Provided is a power conversion device that converts power between DC units and three-phase AC. A first-phase conversion device, a second-phase conversion device, and a third-phase conversion device each include a DC/DC conversion circuit and a single-phase power conversion circuit. For each of the first-phase conversion device, the second-phase conversion device, and the third-phase conversion device, when an absolute value of a voltage target value for the AC exceeds DC voltage of each DC unit, a control unit causes the DC/DC conversion circuit to operate to achieve the absolute value of the voltage target value and causes the single-phase power conversion circuit to only perform necessary polarity inversion, and when the absolute value of the voltage target value is smaller than the DC voltage, the control unit stops operation of the DC/DC conversion circuit and causes the single-phase power conversion circuit to operate to achieve the voltage target value.

Abstract: Provided is a conversion device that converts DC power provided from a DC power supply, to AC power and supplies the AC power to a load, the conversion device including: a filter circuit connected to the load and including an AC reactor and a first capacitor; a DC/AC inverter connected to the load via the filter circuit; a DC/DC converter provided between the DC power supply and the DC/AC inverter; a second capacitor provided between the DC/AC inverter and the DC/DC converter; and a control unit configured to set a current target value for the DC/DC converter to thereby be synchronized with current of the AC power, based on voltage of the AC power, voltage variation due to current flowing through the AC reactor and an impedance thereof, reactive currents respectively flowing through the first capacitor and the second capacitor, and voltage of the DC power.

Abstract: A conversion device includes: a DC bus provided between a DC power supply and an AC power supply; a first converter provided between the DC power supply and the DC bus to perform DC/DC conversion; a second converter provided between the DC bus and the AC power supply to perform DC/AC or AC/DC conversion; and a control unit configured to selectively cause the first converter and the second converter to operate within one cycle of the AC power supply, to alternately generate a part of an absolute value of an AC waveform, and a DC waveform, as voltage of the DC bus, wherein the control unit adds a compensation value in a positive direction, to a voltage target value for the DC bus, at a timing that should have corresponded to a discontinuity point where the AC waveform and the DC waveform are connected to each other.

Abstract: An inverter device includes: a step-up circuit; an inverter circuit; a control unit for controlling the step-up circuit and the inverter circuit; and a reactor provided on an electric path for outputting the converted AC power to an AC system. An output current target value is calculated based on an input power value of DC power and a voltage value of the AC system, and a current target value and a voltage target value for the inverter circuit are calculated based on the output current target value, to control the inverter circuit. A current target value for the step-up circuit is calculated based on a current target value and a voltage target value that are common with the inverter circuit, and on a DC input voltage value, to control the step-up circuit. Thereby, output of the AC power is controlled.

Abstract: An inverter device includes a circuit configuration for converting, to AC power, DC powers respectively given from a first power supply and a second power supply which outputs power with voltage lower than that of the first power supply. The inverter device includes: a first step-up circuit; a second step-up circuit; an inverter circuit connected to both step-up circuits connected in parallel to each other, the inverter circuit configured to convert powers given from both step-up circuits to AC power; and a control unit configured to multiply a power value including the AC power outputted from the inverter circuit, by a ratio of a power value of the DC power of each step-up circuit to a total power value obtained by summing the DC powers of both step-up circuits, and set a current target value for each step-up circuit based on a value obtained by the multiplication.

Abstract: This concentrator photovoltaic system includes: a concentrator photovoltaic panel; a driving device configured to cause the concentrator photovoltaic panel to perform periodical tracking operation with respect to the sun in two axes of azimuth and elevation; a measurement section configured to detect generated power or generated current as an amount of generated electricity of the concentrator photovoltaic panel; and a control section configured to obtain, when the driving device has caused the concentrator photovoltaic panel to perform tracking operation in either one of the two axes, a change in the amount of generated electricity of the concentrator photovoltaic panel before and after the tracking operation, the control section configured to determine presence/absence of tracking deviation that should be corrected, based on the change.

Abstract: Provided is a concentrator photovoltaic system including: a concentrator photovoltaic panel; a driving device configured to cause the concentrator photovoltaic panel to perform operation of tracking the sun; and a control device configured to detect a change pattern repeatedly occurring in temporal change in generated power of the concentrator photovoltaic panel, and configured to compare the detected change pattern with a form characteristic to deviation in an azimuth and a form characteristic to deviation in an elevation, to detect the presence/absence of deviation in tracking.

Abstract: A precursor wire of an oxide superconducting wire includes a first sheath made of silver or silver alloy, a center portion in the first sheath, and a plurality of peripheral segments placed close to one another at the inside of the first sheath so as to surround the center portion. Each of the peripheral segments is formed as a monofilamentary segment that has an arch-shaped cross section and that includes a ribbon-shaped filament made of a precursor of an oxide superconductor and covered with a second sheath made of silver or silver alloy. The multiple peripheral segments are placed in a multilayer state in the form of concentric circles such that wide-width surfaces of the peripheral segments surround the center portion.

Abstract: The present invention provides a Bi2223 oxide superconductor composed of Bi, Pb, Sr, Ln, Ca, Cu, and O, wherein the Ln is at least one selected from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and the composition ratio of Sr to Ln is a composition ratio described below. The Bi2223 oxide conductor has a high critical current density in a magnetic field at low temperature and is capable of maintaining a high critical current density in a self magnetic field even at 77 K. Sr:Ln=(1?x):x (wherein 0.002?x?0.015) Also, the present invention provides a method for producing the Bi2223 oxide superconductor, the method including a step of ionizing a material containing elements, which constitute the Bi2223 oxide superconductor, in a solution; and a step of removing a solvent and causing a thermal decomposition reaction by spraying the solution into a high-temperature atmosphere to produce a powder containing atoms constituting the oxide superconductor.

Abstract: A precursor wire of an oxide superconducting wire includes a first sheath made of silver or silver alloy, a center portion in the first sheath, and a plurality of peripheral segments placed close to one another at the inside of the first sheath so as to surround the center portion. Each of the peripheral segments is formed as a monofilamentary segment that has an arch-shaped cross section and that includes a ribbon-shaped filament made of a precursor of an oxide superconductor and covered with a second sheath made of silver or silver alloy. The multiple peripheral segments are placed in a multilayer state in the form of concentric circles such that wide-width surfaces of the peripheral segments surround the center portion.

Abstract: The invention offers an oxide superconducting wire, a superconducting structure, a method of producing an oxide superconducting wire, a superconducting cable, a superconducting magnet, and a product incorporating the superconducting magnet. The oxide superconducting wire is a tape-shaped oxide superconducting wire in which a plurality of filaments, each of which has a Bi-2223-based oxide superconductor, are embedded in a matrix. The oxide superconducting wire has a cross-sectional area of at most 0.5 mm2 in a cross section perpendicular to the direction of its length. In the cross section of the oxide superconducting wire, the filaments have an average cross-sectional area per filament of at least 0.2% and at most 6% of the cross-sectional area of the oxide superconducting wire. Having the above features, the oxide superconducting wire can not only increase its critical current density but also decrease its AC loss.

Abstract: The invention offers a superconducting tape that maintains both high allowable tension and low splice resistance and a method of producing the superconducting tape. The superconducting tape is provided with a main-body portion and a reinforcement portion. The main-body portion has the shape of a tape and has a superconductor. The reinforcement portion is composed of precipitation-hardened-type copper alloy or alloy of tin and copper and is formed on at least one surface side of the main-body portion.

Abstract: The invention offers a production method of a material powder of an oxide superconductor. The production method is provided with both a step of producing a dry powder by removing solvent from a solution containing elements for constituting the oxide superconductor and a step of producing oxides of the elements for constituting the oxide superconductor by scattering the dry powder in a high-temperature furnace. Provided with the above steps, the production method not only can achieve the uniform presence of the elements for constituting the oxide superconductor but also enables the mass production of the material powder.

Abstract: A method of producing a material of an oxide superconductor comprises the following steps: (a) in a solution, ionizing a material containing an atom for constituting the oxide superconductor, (b) by removing a solvent by spraying the solution in a first atmosphere, producing a material powder containing the atom for constituting the oxide superconductor, and (c) cooling the material powder in a second atmosphere into which a cooling gas is introduced. In this method, the concentration of carbon dioxide in the second atmosphere is lower than that in the first atmosphere, which contains the removed solvent component. The concentration of nitrogen oxide in the second atmosphere is lower than that in the first atmosphere, which contains the removed solvent component. The concentration of water vapor in the second atmosphere is lower than that in the first atmosphere, which contains the removed solvent component. These specifications enable the method to increase the density and purity of the oxide superconductor.

Abstract: An object of the present invention is to provide a method of manufacturing a bismuth-based oxide superconductor capable of obtaining a high critical current density and a superconducting wire containing a bismuth-based oxide superconductor manufactured by this method. The present invention is directed to a method of manufacturing a bismuth-based oxide superconductor containing a 2223 phase having a 2223 composition in a composition Bi—Sr—Ca—Cu or (Bi,Pb)—Sr—Ca—Cu, comprising a first step of charging a raw material containing a 2212 phase having a 2212 composition in a composition Bi—Sr—Ca—Cu or (Bi,Pb)—Sr—Ca—Cu with a critical temperature of not more than 70 K into a metal sheath, a second step of performing plastic working on the metal sheath charged with the raw material and a third step of performing heat treatment on the metal sheath charged with the raw material.