Abstract: A synchronization control circuit transforms a three-phase AC voltage supplied from a commercial AC power supply to a vector on rotational coordinates and calculates a first phase difference between the vector and a d axis. When magnitude of the first phase difference is larger than a prescribed value, the synchronization control circuit sets the first phase difference as it is as a second phase difference. When magnitude of the first phase difference is smaller than the prescribed value, the synchronization control circuit generates the second phase difference in reverse polarity to the first phase difference, and controls a frequency of a clock signal so as to set the second phase difference to 0 degree.

Abstract: A system frequency detector includes an orthogonal coordinate signal generator generating an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power of a power system by converting the three-phase voltage signal into a two-phase voltage signal orthogonal to the three-phase voltage signal, converting the two-phase voltage signal into a voltage signal of a rotating coordinate system, calculating a moving average of the voltage signal of the rotating coordinate system, and performing an inverse transformation of the voltage signal of the rotating coordinate system after calculating the moving average; and a frequency calculator including an angular frequency calculator calculating an angular frequency of the power system based on the two-phase voltage signal, and an arithmetic unit calculating a system frequency of the power system from the angular frequency, the frequency calculator further including a low-pass filter provided in series with the arithmetic

Abstract: According to an embodiment, a capacitor diagnosis device includes a sensor, a frequency spectrum analysis unit, a frequency component extraction unit, and a diagnosis processing unit. The sensor detects a physical quantity that changes with an current flowing through a capacitor in a power conversion unit (PCU) for converting DC power smoothed by the capacitor connected in parallel to DC link(s) into AC power according to a power running operation. The frequency spectrum analysis unit generates a frequency spectrum based on a detection result of the sensor detected during the power running operation of the PCU. The frequency component extraction unit extracts a component of a specific frequency band related to a frequency depending on a configuration of the PCU based on the frequency spectrum. The diagnosis processing unit diagnoses a state of the capacitor based on at least a magnitude of the extracted component of the specific frequency band.

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.

Abstract: An explosion-proof structure of an electronic device includes a housing, a cover member, and an opening/closing member. The housing houses electronic components. The cover member covers a first ventilation port formed on one surface of the housing at least in a normal direction to the one surface. The opening/closing member opens and closes a second ventilation port formed between one surface and the cover member.

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 power conversion device according to an embodiment includes an element unit and a capacitor unit. The element unit includes a first positive electrode bus, a first negative electrode bus, and a first outer frame member. The capacitor unit includes a second positive electrode bus, a second negative electrode bus, and a second outer frame member. The first outer frame member and the second outer frame member are separable from each other. The first positive electrode bus and the second positive electrode bus are removably connected to each other. The first negative electrode bus and the second negative electrode bus are removably connected to each other.

Abstract: A rolling controller executes speed and tension control, and roll gap and plate thickness control when rolling speed is less than a boundary value, while executing roll gap and plate tension control, and speed and plate thickness control when the rolling speed is equal to or greater than the boundary value. If the rolling speed rises across the boundary value, the rolling controller sets the rolling speed to zero such that a speed correction amount in the speed and tension control before the transboundary is not reflected to a calculation executed in the speed control amount of the rolling speed after the transboundary.

Abstract: A power conversion device includes: a first control unit and a second control unit that output a first control signal and a second control signal, respectively; a gate circuit that causes a control signal selected from the first control signal and the second control signal to pass through the gate circuit; and a drive circuit that drives a main circuit based on the control signal that passes through the gate circuit. When the second control signal is selected in the state where the first control signal passes through the gate circuit, the gate circuit interrupts the first control signal and causes the second control signal to pass through the gate circuit as an absolute value of an instantaneous value of an AC current decreases below a threshold current.

Abstract: In the present invention, a gas passing groove, a high-voltage electrode groove and a ground electrode groove formed in an electrode unit base are each spiral in plan view. A high-voltage electrode is embedded in the high-voltage electrode grove, and a ground electrode is embedded in the ground electrode groove. The high-voltage electrode and the ground electrode are arranged on sides of opposite side surfaces of the gas passing groove in the electrode unit base to oppose each other with a portion of the electrode unit base and the gas passing groove therebetween, and are spiral in plan view along with the gas passing groove.

Abstract: A power conversion unit includes a plurality of semiconductor modules, a gate drive circuit, a first substrate having a flat plate shape, and a second substrate having a flat plate shape. The first substrate has a first surface facing a bottom plate of a casing accommodating the semiconductor modules and the gate drive circuit, and a second surface on an opposite side to the first surface. The second substrate is arranged above the first substrate in parallel with the second surface. The semiconductor modules are mounted on the first surface. The gate drive circuit is formed on a surface of the second substrate on a side that does not face the second surface. The power conversion unit further includes a connector provided on the second surface and connected to a surface on a side facing the second substrate.

Abstract: In an ultrasonic atomization apparatus being the present invention, a source solution is accommodated in a separator cup being a part of a container. A constituent material of the separator cup is PTFE being one of fluorocarbon resins, whose entire thickness is uniformly 0.5 mm. Therefore, the separator cup satisfies a thin film condition that “the thickness of a bottom surface BP1 is 0.5 mm or less”.

Abstract: A control device of an uninterruptible power supply apparatus turns on a first switch and a second switch and turns off a third switch in an inverter power feed mode, turns on the first and third switches and turns off the second switch in a bypass power feed mode, and executes a lap power feed mode of turning off the first switch and turning on the second and third switches in a switching period in which one mode of the inverter power feed mode and the bypass power feed mode is switched to the other mode.

Abstract: The power conversion system includes a power conversion circuit, a power conversion control circuit including a charging control mode, and a command value generating part. The charging control mode is a mode in which the output voltage of the power conversion circuit is controlled so that an interconnection inductance receives an interconnection inductance voltage determined by the power supply voltage vector of the AC power supply and the voltage command value vector having a delay phase with respect to the power supply voltage vector and having a magnitude and a phase based on the command value. The command value generating part generates a second command value for operation of the charging control mode when the voltage of the storage battery falls below the over-discharge threshold.

Abstract: A plate thickness schedule calculation method includes a plurality of steps. One step acquires a rolling model expression including a roll force model or a motor power model. Another step determines whether or not a parameter restriction has occurred that restricts at least one parameter of roll force, motor power and a reduction rate in each rolling stand. Further another step is to select a first derived function when no parameter restriction occurs and to select a second derived function when the parameter restriction has occurred in accordance with a result of the determination for each rolling stand. Still another step modifies each delivery side plate thickness in each rolling stand using a matrix including the one derived function selected from the first derived function and the second derived function in accordance with the result of the determination.

Abstract: An uninterruptible power supply device includes: a converter that converts AC power supplied from an AC power supply into DC power and outputs the DC power to a first power supply node; a first bidirectional chopper that outputs DC power in a lead storage device to the first power supply node when the AC power supply has a power failure; a diode connected between the first power supply node and a second power supply node; a second bidirectional chopper that supplies and receives DC power between the second power supply node and a lithium ion battery; and a controller that controls the second bidirectional chopper to charge the lithium ion battery during regenerative operation of a load and to discharge the lithium ion battery during power running operation of the load.

Abstract: An element module includes a cooler, a plurality of elements, and a conductive member. The cooler includes a first element disposition portion and a second element disposition portion which are provided on both sides in a predetermined direction. The plurality of elements are disposed in each of the first element disposition portion and the second element disposition portion. The conductive member is disposed in a space portion of the cooler. The space portion penetrates the cooler between the plurality of elements in each of the first element disposition portion and the second element disposition portion. The space portion allows the first element disposition portion and the second element disposition portion to communicate with each other. The conductive member is connected to the element of the first element disposition portion and the element of the second element disposition portion.

Abstract: The uninterruptible power supply device includes a switch (2) that includes first to Nth IGBT units (U1 to UN) connected in series, and a controller that turns on the switch by turning on the first to Nth IGBT units, and turns off the switch by firstly turning off the first to nth IGBT units and then turning off the (n+1)th to Nth IGBT units. Compared with the case where the first to Nth IGBT units are turned off at the same time, it is possible to reduce a surge voltage generated between the terminals of the switch (2).

Abstract: A power conversion device includes a three-level inverter circuit and an inverter control circuit for driving the three-level inverter circuit in a double carrier modulation manner. The inverter control circuit includes a command value calculating part generating three-phase output voltage command values, a command value correcting part outputting corrected command values by correcting to the three-phase output voltage command value, and a gate signal generating part generating a gate signal based on the corrected command values. The command value correcting part is configured to output a predetermined voltage command value corresponding to an end of a dead band instead of one AC voltage command value, and distribute a difference between the one AC voltage command value and the predetermined voltage command value in the dead band passage period to other two AC voltage command values, during a dead band passage period.

Abstract: A power conversion device includes: a power conversion circuit for converting DC power into AC power; and a controller to generate a control signal for the power conversion circuit based on a control command value and an output voltage of the power conversion circuit. The controller is configured to generate the control signal based on a corrected voltage command value calculated by subtraction correction to decrease a voltage command value when the output voltage of the power conversion circuit is equal to or higher than a predetermined threshold value, and to generate the control signal based on a voltage command value not subjected to the subtraction correction when the output voltage of the power conversion circuit is lower than the threshold value.