Abstract: A power measurement device includes: a first three-phase to two-phase converter converting a three-phase voltage signal of three-phase AC power into a two-phase voltage signal; a second three-phase to two-phase converter converting a three-phase current signal of the three-phase AC power into a two-phase current signal; an instantaneous power calculator calculating an instantaneous value of active power of the three-phase AC power and an instantaneous value of reactive power of the three-phase AC power based on the two-phase voltage signal and the two-phase current signal; a first moving average calculator calculating multiple active power average values of different moving average data quantities; a second moving average calculator calculating multiple reactive power average values of different moving average data quantities; and calculators that calculate average active powers corresponding to a frequency of the three-phase AC power, and the reactive power corresponding to the frequency of the three-phase A

Abstract: An AC switch that includes a semiconductor switch and a snubber circuit connected in parallel between a first terminal connected to an AC power supply via a circuit breaker and a second terminal connected to a load. The power converter is connected between a power storage device and the second terminal. The current detector detects a current flowing through the AC switch. When the AC power supply is normal, the controller turns on the semiconductor switch. When an open state of the circuit breaker is detected, the controller controls the power converter to supply a current having a phase opposite to that of the current detected by the current detector to flow through the semiconductor switch and supply the AC power to the load. The controller further turns off the semiconductor switch in response to that the amplitude of the current detected by the current detector is 0.

Abstract: A SCADA Web HMI system includes a drawing generation device (1) and an HMI terminal device (32). A drawing editor (11) generates SVG data (21) and part runtime attribute data (22). The HMI terminal device (32) includes a Web browser (321) that reads SVG data (21) and displays an HMI screen, and an HMI Web runtime (322) that reads the part runtime attribute data (22) as setting parameters and operates on the Web browser (321). When receiving signal data corresponding to unique signal names from a monitoring target device (7), the HMI Web runtime (322) changes display of parts corresponding to the unique signal names on the HMI screen.

Abstract: An object of the present invention is to provide a SCADA web HMI system that can reduce a load for processing input/output signals in a large-scale system. An HMI server apparatus performs three filtering processing. In first filtering processing, in a case where received block data corresponds to a screen currently displayed on a web browser, a set of input/output signals is extracted from the received block data. In second filtering processing, input/output signals each having a value varied from a previous value are extracted from the set of input/output signals extracted in the first filtering processing. In third filtering processing, input/output signals corresponding to display parts arranged in the screen currently displayed on the web browser, are extracted from the input/output signals extracted in the second filtering processing.

Abstract: A master device of a drive system transmits identification information of each first period and a first transmission synchronization signal for each first period of a reference period. A first controller adjusts a phase of each first control period such that the first control period is synchronized with a timing associated with a specific first synchronization signal. A second controller adjusts a phase of each second control period such that the second control period is synchronized with a timing associated with a specific second synchronization signal.

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 partition member is disposed in a space portion between a rear surface of a housing and outer surfaces of a plurality of units. A first partition portion is disposed in a boundary portion between two units adjacent to each other in a vertical direction and extends in a right-left direction. A second partition portion and a third partition portion each are connected to a corresponding one of both ends of the first partition portion in the right-left direction and extend toward the upper surface. Air discharged from a first unit group located above the first partition portion is guided to flow through a first air channel to the upper surface. Air discharged from a second unit group located below the first partition portion is guided to flow through a second air channel to the upper surface.

Abstract: In this power conversion device, first three-phase AC voltages generated by an inverter and an AC filter are divided by first to third voltage dividers to generate second three-phase AC voltages, and third three-phase AC voltages that are line-to-line voltages of the second three-phase AC voltages and a neutral point voltage of the first three-phase AC voltages are detected. Then, DC components of the third three-phase AC voltages resulting from errors of voltage ratios of the first to third voltage dividers are obtained based on the detection results and contents in a storage unit, the DC components are removed from the third three-phase AC voltages to generate fourth three-phase AC voltages, and the inverter is controlled such that DC components of the fourth three-phase AC voltages are eliminated.

Abstract: A plurality of semiconductor switches and a mechanical switch are connected in series between a first terminal and a second terminal. A plurality of voltage detectors are provided corresponding to the plurality of semiconductor switches, respectively, and detect terminal-to-terminal voltages of the corresponding semiconductor switches. A plurality of drivers are provided corresponding to the plurality of semiconductor switches, respectively, and turn off the corresponding semiconductor switches in response to control signals from a main controller. Each driver determines whether or not a terminal-to-terminal voltage of the corresponding semiconductor switch matches a terminal-to-terminal voltage of another semiconductor switch of the plurality of semiconductor switches, and outputs a result of determination.

Abstract: A power converter includes a power conversion circuit including a direct-current terminal connected to a solar cell panel, and an alternating-current terminal connected to an alternating-current power system, the power conversion circuit being configured to convert direct-current power generated by the solar cell panel into alternating-current power and to supply the alternating-current power to the alternating-current power system; a current detection unit configured to detect a direct current flowing between the solar cell panel and the power converter; and a control circuit including a power generation mode in which the control circuit controls the power conversion circuit to output active power generated from the direct-current power generated by the solar cell panel to the alternating-current power system, and a reactive power compensation mode in which the control circuit controls the power conversion circuit to output reactive power to the alternating-current power system, the control circuit being con

Abstract: An electric-power converter includes a plurality of direct-current power supplies, a plurality of power conversion circuits provided corresponding to the respective direct-current power supplies, an alternating-current power system configured to cause a plurality of alternating-current ends provided in the respective power conversion circuits to be directly connected in parallel through a parallel connection point, and to supply the alternating-current power output from the plurality of alternating-current ends to an alternating-current side through the parallel connection point, a plurality of grounding wires each configured to connect at least two of a plurality of direct-current negative buses between the plurality of direct-current power supplies and the plurality of power conversion circuits, to earth, and a plurality of diodes inserted in series into the respective grounding wires, and each including a cathode side connected to the corresponding direct-current negative bus and an anode side grounded.

Abstract: A connection structure includes a circuit board, an insulating member, a housing, and a conductive wire. The insulating member includes a first portion and a second portion. The first portion is fixed to the circuit board. The second portion faces the first portion. The second portion is fixed to the housing. The housing includes a grounded contact. The conductive wire electrically connects the circuit board and the housing while being wound around the insulating member. A shortest distance along a surface of the housing from a position where the conductive wire and the housing are connected to the contact is shorter than a shortest distance along a surface of the housing from the second portion of the insulating member to the contact.

Abstract: A power conversion apparatus is provided to prevent the arc flash generated in a board from flowing out to a operation surface for operating the board, and also to relieve the pressure inside the board to the outside from the flapper section provided on the ceiling. The power conversion apparatus that has taken measures against an arc flash composed of a power converter and a board accommodating the power converter is provided. A BUS which constitutes the power converter has the first processing that makes it hard to fly the flash in a place where arc flash is not desired to occur. A door is placed on the front board that can be opened and closed by the operator. The board has an explosion-proof shutter part to prevent the arc flash from being released to the outside by the pressure inside the board, and has a flapper section for releasing the pressure inside the board to the outside from the ceiling of the board unit, when the arc flash occurs.

Abstract: An elevator monitoring device that can compensate for system voltage when an unbalanced short circuit occurs. A control device for a power conversion device includes: a current command value generator configured to generate a provisional normal phase d-axis current command value, a provisional normal phase q-axis current command value, a provisional reversed phase d-axis current command value, and a provisional reversed phase q-axis current command value to compensate for an alternating current (AC)-side voltage of a power converter; a limiter configured to respectively set limit values of a provisional normal phase d-axis current command value, a provisional normal phase q-axis current command value, a provisional reversed phase d-axis current command value, and a provisional reversed phase q-axis current command value so that the AC-side current value of the power converter does not exceed a preset value; and a controller configured to control the power converter within the limit values.

Abstract: According to an embodiment, an electric motor drive device includes an electric motor, a main circuit, a current sensor, and a control unit. The electric motor has a plurality of windings. The main circuit transforms power of an alternating current (AC) power supply into AC power and supplies the AC power to each of the plurality of windings. The current sensor detects a load current flowing through each of the plurality of windings. The control unit controls the main circuit on the basis of a current value detected by the current sensor. The control unit controls an amount of power to be supplied from the main circuit to the electric motor on the basis of an amplitude of the load current associated with detection of an undervoltage state of the AC power supply in a state in which the main circuit uses a conversion rule in which an index value for the amplitude of the load current flowing through the plurality of windings is defined.

Abstract: A bidirectional chopper selectively performs a charging operation and a discharging operation, the charging operation being an operation in which a part of DC power generated by a converter is stored in a power storage device, the discharging operation being an operation in which DC power of the power storage device is supplied to an inverter. A control circuit controls the bidirectional chopper to perform the discharging operation when a power failure of a power system occurs. The control circuit controls the bidirectional chopper based on a system frequency detected by a frequency detector when the power system is normal. The control circuit controls the bidirectional chopper to perform the charging operation in response to an increase in the system frequency, and to perform the discharging operation in response to a decrease in the system frequency.

Abstract: A power conversion device includes a first control device to an m-th control device that are capable of communicating with each other. A k-th control device transmits specific information to control devices other than the k-th control device among the first control device to the m-th control device. The specific information includes voltage values of a plurality of unit converters included in a k-th cell set in each of a first arm to a third arm. From each control device other than the k-th control device among the first control device to the m-th control device, the k-th control device receives specific information including the voltage values of the plurality of unit converters. The k-th control device calculates a phase representative value of the voltage values of the plurality of unit converters included in each of the first arm to the third arm.

Abstract: The electric motor speed control apparatus in an embodiment comprises a rotation speed estimation unit and a control unit. The rotation speed estimation unit generates an estimated value of a rotation speed of an electric motor by using a result of FFT analysis of a speed detection signal ?FBK, which is based on a detection result from a resolver for detecting the rotation speed of the electric motor, and the speed detection signal ?FBK. The control unit implements speed control so as to reduce deviation between the estimated value of the rotation speed and a speed command value for speed control of the electric motor.

Abstract: A wind power generation system includes a power generator body, an auxiliary device that assists the power generator body, and a power conversion apparatus that converts first AC power generated by the power generator body to second AC power, and outputs the second AC power to an electric power grid. The power conversion apparatus includes a first power conversion circuit, a second power conversion circuit, a power storage element that receives DC power from the first power conversion circuit via a first passing point, a breaker, and a control unit. When the power generator body is in a power generation standby state, the control unit sets a parallel-off mode and controls the second power conversion circuit to convert power of the power storage element to third AC power having a preset voltage. The auxiliary device is configured to receive the second AC power or the third AC power.

Abstract: A lead wire storage mechanism stores most of a lead wire such that the lead wire can be taken out from a tip end portion. A tension adjusting mechanism including a dancer roller and two lifting and lowering guide rollers is formed with a partial space that is to be a part of a hand travel space at a time of a preparation state. A lead wire guide mechanism including an opening and closing lead guide is formed with a partial space that is to be a part of the hand travel space at the time of the preparation state. A lead wire grasping and moving mechanism can execute a grasping operation for grasping a tip end portion of the lead wire with a grasping part, and a grasping part moving operation for moving the grasping part through the hand travel space.