Abstract: A main circuit power supply device includes: a plurality of voltage-division power storage elements connected in series; voltage adjustment circuits for adjusting each of voltages of the plurality of voltage-division power storage elements through mutual transfer of power between the plurality of voltage-division power storage elements; and at least one DC/DC converter which is connected to at least one of the voltage-division power storage elements and supplies a control power source to a main circuit control circuitry to control a main circuit.

Abstract: A power converter includes a cabinet and an electric device accommodated in the cabinet. The cabinet includes a housing, a door, a support member, and a rotation mechanism. The door is rotatably supported around a first axis with respect to the housing. The support member is interposed between the housing and the door to support the door in the housing. The rotation mechanism rotates the door with respect to the housing around a second axis along a direction orthogonal to a plane direction of an opening of the housing.

Abstract: A power conversion device is connected to a power transmission line which is connected to a generator. The power conversion device includes a frequency detector that detects a system frequency, the system frequency being a frequency of an AC voltage on the power transmission line, a controller that generates a reactive power command value to compensate for a variation in the detected system frequency, and a power converter that outputs reactive power in accordance with the reactive power command value to the power transmission line.

Abstract: A power conversion system includes plural power conversion apparatuses and a server connected to each of the plural power conversion apparatuses. Each of the plural power conversion apparatuses includes a power conversion circuit interconnected with a power system, a calculating unit configured to calculate, based on an output current and an output voltage of the power conversion circuit, at least one information of reactive power and a reactive current output by the power conversion circuit, a storing unit configured to accumulate, in a storage device, time-series reactive power information which is information associating time and the at least one information calculated by the calculating unit, and a communication interface configured to transmit the time-series reactive power information stored in the storage device to the server. The server is constructed to collect the time-series reactive power information of each of the plural power conversion apparatuses via the communication interface.

Abstract: A steel plant control device includes a subtractor, a PI controller, a first-order lag controller, and an adder. In a band that is lower than a first frequency f1, a gain of the PI controller is higher than a gain of the first-order lag controller; in a band from the first frequency f1 to a second frequency f2, the gain of the first-order lag controller is higher than the gain of the PI controller; and in a band that is higher than the second frequency f2, the gain of the PI controller is higher than the gain of the first-order lag controller.

Abstract: An AC/DC converter converts an AC voltage supplied from an AC power supply into a first DC power supply voltage. A power supply line transmits the first DC power supply voltage to a plurality of power conversion modules and a bypass module. The bypass module includes a switch connected between the AC power supply and the load, and a first controller that operates upon receiving an operating power supply voltage based on the first DC power supply voltage to thereby control ON/OFF of the switch. Each power conversion module includes a power converter that converts power supplied from the AC power supply or a power storage device into AC power and supplies the AC power to the load, and a second controller that operates upon receiving an operating power supply voltage based on the first DC power supply voltage to thereby control the power converter.

Abstract: A power conversion system includes: a power converter connected to an alternate-current power supply; a direct-current capacitor connected to a direct-current side of the power converter; a first alternate-current switch connected between the power converter and the alternate-current power supply; an inrush current suppressor connected in parallel to the first alternate-current switch, between the power converter and the alternate-current power supply, and including a charging resistance or a charging reactor; a second alternate-current switch connected in parallel to the first alternate-current switch and in series to the inrush current suppressor, between the power converter and the alternate-current power supply; and a control device configured to control the power converter so that the first alternate-current switch is open, the second alternate-current switch is closed, and a voltage applied to the direct-current capacitor reaches a voltage that is equal to or exceeds a preset voltage.

Abstract: A power conversion device in an embodiment includes a first power converter; a plurality of direct current-direct current (DCDC) converter devices; and a second power converter. The first power converter includes a plurality of first positive-side arms; a plurality of first negative-side arms; a first positive-side star connection line configured to connect the plurality of first positive-side arms in a star shape; a first negative-side star connection line configured to connect the plurality of first negative-side arms in a star shape; and a first terminal configured to connect the first positive-side star connection line and the first negative-side star connection line to each phase of a power supply side alternating current (AC) system and the plurality of first positive-side arms and the plurality of first negative-side arms mutually convert a first AC power and a first DC power of the power supply side AC system.

Abstract: A reactive power compensation device includes a power converter and a converter control unit, and compensates reactive power of an AC power grid by output reactive power of the power converter. The converter control unit includes an AC voltage detection unit and an output limit unit. The AC voltage detection unit detects voltage information of the AC power grid to which the power converter is connected. The output limit unit determines whether or not the output reactive power of the power converter needs to be limited, on the basis of the voltage information detected by the AC voltage detection unit, and in a case where the output reactive power needs to be limited, limits the output reactive power of the power converter.

Abstract: A fan unit is disposed on an upper surface of a housing, and includes a fan, a frame member, and a support member. The frame member is disposed to surround an outer circumference of an opening provided in an upper surface of the housing. The support member supports the fan above the opening while being fixed to the frame member. A gap is provided between a lower end of a first surface of the frame member and the upper surface of the housing. A first blocking member is connected to the first surface of the frame member to be slidable in a vertical direction. In a state in which the gap is exposed, at least one second blocking member is inserted through the gap into the frame member to block the opening in the upper surface of the housing.

Abstract: In thickness control processing, transfer processing of an entry thickness He(N) is performed (step S1). In the transfer processing, data of the entry thickness He(N) is transferred from a position P11 to a position P12 at the same speed as the speed of a material to be rolled M. Subsequently, an amount of change in a thickness ?H(N) is calculated (step S2). The amount of the change in the thickness ?H(N) is calculated based on data of a delivery thickness Hd(N) and data of a transferred thickness Hc(N) transferred to the position P12 at a timing when the data of the delivery thickness Hd(N) is measured. Then, a target entry thickness He(N)_tgt is calculated (step S3). Subsequently, a manipulated amount of rolling speed VR(N?2) and VR(N?k) are calculated (step S4).

Abstract: A resin producing method is a method of producing a resin with which an insulating structure formed on an outer peripheral portion of a conductor is impregnated. The resin producing method includes a dispersion liquid mixing step of mixing an epoxy resin and a dispersion liquid in which a nanofiller is dispersed in a reactive diluent that reduces a viscosity of the epoxy resin by reacting with the epoxy resin, and a curing agent mixing step of mixing a composition produced by the dispersion liquid mixing step, with a curing agent that cures the epoxy resin. The epoxy resin includes, for example, an alicyclic epoxy resin.

Abstract: A control apparatus is a control apparatus for a power conversion apparatus including at least one AC capacitor disposed on the output side of an inverter and disconnected from a circuit when the AC capacitor malfunctions and including a current component extractor that acquires current values of the current flowing through the AC capacitor during synchronization control that synchronizes the output voltage from the inverter with a system voltage of a system, the synchronization control performed during activation of the power conversion apparatus with an AC switch on the side facing the system open, and extracts the value of a current component having a frequency synchronized with the frequency of the output voltage from the inverter out of the current values.

Abstract: A power conversion device includes: an inverter that includes a switching element and converts DC power into AC power; a current detector that detects an output current of the inverter; and a controller that controls the inverter to allow the output current detected by the current detector to follow a current command value having a sinusoidal waveform. The controller compares a current deviation of the output current from the current command value with a hysteresis band to control switching of the switching element. The controller sets the hysteresis band so that a hysteresis band in a zero-crossing area of the current command value is smaller than a hysteresis band in a peak area of the current command value.

Abstract: In the present invention, an electrode pair having a discharge space therein is constituted by a combination of a high-voltage application electrode unit and a ground potential electrode unit. The high-voltage application electrode unit has, as the main components, an electrode dielectric film and a metal electrode formed on the upper surface of the electrode dielectric film. An auxiliary conductive film is formed in an annular shape so as to surround the metal electrode without overlapping the metal electrode in plan view. A metal electrode pressing member: has an annular shape in plan view; is provided to contact part of the upper surface of the auxiliary conductive film; and is fixed to a metal base flange. A ground potential is applied to the base flange.

Abstract: An electric power conversion apparatus of an embodiment includes a DC-side terminal and a heat release member. The heat release member is electrically conductive. The heat release member is provided on the DC-side terminal.

Abstract: A gate drive circuit of an uninterruptible power supply apparatus generates first and second gate drive signals in response to first and second PWM signals, and alternately turns on first and second IGBTs. When the first IGBT is on, the gate drive circuit sets the first gate drive signal to the “L” level in response to the second PWM signal and sets the second gale drive signal to the “H” level in response to a voltage across terminals of the first IGBT exceeding a threshold voltage.

Abstract: A fan drip-proof structure of an embodiment includes a housing, one or more open-close members, and a regulation member. The housing accommodates a fan. The one or more open-close members open and close a vent port formed on the housing in response to a wind force of an air flow of the fan. The regulation member regulates an open degree of the vent port by the open-close member.

Abstract: A power conversion device of an embodiment includes a rectifier that full-wave rectifies alternating current of a plurality of phases supplied from a power supply side, a capacitor that smoothes an output voltage of the rectifier, a voltage detection unit that detects the smoothed voltage, and an open phase detection unit that detects that an open phase has occurred in the alternating current of the plurality of phases based on a component having a frequency that is twice as high as a fundamental frequency of the alternating current of the plurality of phases included in frequency components of the smoothed voltage.

Abstract: A control device for a power converter that can suppress oscillation of an output voltage of the power converter. The control device for the power converter includes an overvoltage detector configured to detect an overvoltage on an output side of the power converter and a controller configured to, when the overvoltage on the output side of the power converter is detected by the overvoltage detector, perform gate block after reducing a current command value given to the power converter. With the configuration, when the overvoltage on the output side of the power converter is detected, the control device performs the gate block after reducing the current command value given to the power converter. Accordingly, it is possible to suppress oscillation of an output voltage of the power converter.