Abstract: A system includes an orthogonal coordinate signal generator that generates an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power of a power system; 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. A prediction calculator calculates a predicted value of the angular frequency after a time has elapsed based on the angular frequency and a differential of the angular frequency. In a state in which the phase jump of the power system is not detected, the frequency calculator calculates the system frequency based on the angular frequency. When the phase jump of the power system is detected, the frequency calculator calculates the system frequency based on predicted value for a constant amount of time.

Abstract: A control device for a power converter includes a voltage command value limiting unit configured to limit each phase component or an absolute value of a vector of a voltage command value to be equal to or less than a value set in advance. With such a configuration, the control device for the power converter limits each phase component or the absolute value of the vector of the voltage command value to be equal to or less than the value set in advance. Therefore, it is possible to prevent overvoltage of the output from the power converter when impedance rapidly increases on the output side of the power converter.

Abstract: The semiconductor device according to the present invention includes a semiconductor module, a cooling member, and a heat transfer member. The semiconductor module includes a switching element and a diode connected in antiparallel to each other. The heat transfer member is disposed between the semiconductor module and the cooling member so as to transfer heat generated by the switching element and the diode to the cooling member. The heat transfer member has a mounting surface on which the switching element and the diode are mounted side by side and a surface which is opposite to the mounting surface and is disposed in contact with the cooling member. In the heat transfer member, the thermal conductivity in a first direction parallel to the mounting surface is higher than the thermal conductivity in a second direction perpendicular to the mounting surface.

Abstract: A cooling-water injection control device and a cooling-water injection control method for a rolling mill suppress influence by change in flow rate characteristics of water injection headers. The cooling-water injection control device for a rolling mill includes a water injection amount control unit. When a plurality of water injection headers are controlled to make temperature of a material to be rolled on a delivery side of a rolling mill coincident with a target value, in a case where a flow rate of any one of the plurality of water injection headers is less than a transient flow rate between a minimum flow rate and a maximum flow rate, the water injection amount control unit controls a flow rate of any one of the plurality of water injection headers based on priority.

Abstract: In the present invention, a high-voltage side electrode component further includes a conductive film disposed on an upper surface of a dielectric electrode independently of a metal electrode. The conductive film is disposed between at least one gas ejection port and the metal electrode in plan view, and the conductive film is set to ground potential.

Abstract: A metal laminating/shaping device includes a base, a head unit including a base material injection device, and drive devices that change a positional relationship between the base and the head unit in a spatial coordinate system. The base material injection device includes a base material heating unit that heats a base material that is a metal piece having a fixed shape such that a temperature of an interior of the base material is raised to a temperature below a melting point and a temperature of a surface of the base material is raised to the melting point, and a base material injection unit that injects the heated base material toward the base. The metal laminating/shaping device can form a metal shaped article having a complicated structure at a low cost.

Abstract: An uninterruptible power supply apparatus includes: an electromagnetic contactor including a first terminal that receives a first AC voltage supplied from an AC power supply and a second terminal connected to an AC node; a capacitor that is connected to a DC line and stores DC power; a converter that transmits and receives electric power between the AC node and the DC line; and a controller. In an activation mode, the controller turns on the electromagnetic contactor after controlling the converter such that a frequency and a phase of a second AC voltage supplied from the converter to the AC node match a frequency and a phase of the first AC voltage. In a normal operation mode after the activation mode, the controller controls the converter such that a DC voltage of the DC node attains to a reference voltage.

Abstract: An uninterruptible power supply device includes a bidirectional chopper that converts a first DC voltage supplied from a battery into a second DC voltage and supplies the second DC voltage to an inverter when a power failure of a commercial AC power supply occurs. The bidirectional chopper includes a capacitor that stabilizes the second DC voltage. The uninterruptible power supply device further includes: a current detector that detects an output current of the battery; and a control circuit that, based on a detection result by the current detector, calculates an estimated temperature increase value of the capacitor every time a predetermined time period elapses, and stops an operation of the bidirectional chopper when the calculated estimated temperature increase value is higher than an upper limit value.

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: A control device for a power conversion apparatus and a resistor for a power conversion apparatus that can suppress a cross current between a plurality of power converters. A control device for a power conversion apparatus includes, in a state that AC sides of a plurality of power converters are connected in parallel without DC sides of the plurality of power converters being connected in parallel: a voltage recognition unit configured to recognize a voltage to ground on a DC side of a power converter, being an object to be controlled; and a controller configured to control, based on the voltage to ground on the DC side recognized by the voltage recognition unit, a DC voltage of the power converter, being the object to be controlled, such that the voltage to ground on the DC side of the power converter, being the object to be controlled, is further reduced.

Abstract: A controller of a power conversion device including a power converter connected between a direct current (DC) power supply and an alternating current (AC) power supply, includes: a damping control term calculation unit configured to calculate a value of pulsation of a DC voltage applied between the DC power supply and the power converter, or pulsation of a DC current flowing between the DC power supply and the power converter; and a current control unit configured to output, to the power converter, a command value for adjusting the power of the power converter so that a pulsation component corresponding to the pulsation value calculated by the damping control term calculation unit is reduced in accordance with a command value based on the value calculated by the damping control term calculation unit. The power conversion device can reduce resonance without including a damping resistor.

Abstract: A SCADA web HMI system generates an integrated component by grouping components including a first component and provides a first animation effect to the integrated component. The first animation effect is applied to the integrated component as a whole but not individually applied to components constituting the integrated component. The system provides a second animation effect to the first component. The second animation effect is applied to the first component but not applied to the components constituting the integrated component except for the first component. The system associates the first animation effect with the value of a first PLC signal and changes the appearance of the integrated component according to the value of the first PLC signal. The system associates the second animation effect with the value of a second PLC signal and changes the appearance of the first component according to the value of the second PLC signal.

Abstract: A protection system including: a DC power supply; a power converter that converts DC power of the DC power supply into AC power, a circuit breaker that is series-connected to an electrical path located between the DC power supply and the power converter and can open the electrical path; a DC capacitor connected to a circuit located in the power converter; a timer that counts a lapse of a predetermined length of time from turn-on of the circuit breaker; a current detector that detects current flowing in the power converter; and a protection determiner that issues an open operation command to the circuit breaker when the current detector does not detect a decrease in the current after the timer has counted a lapse of the predetermined length of time from turn-on of the circuit breaker.

Abstract: A controller for a power conversion system includes a determination unit configured to determine whether a current time is in nighttime in an environment of a power converter that is connected to one or both of a direct-current power supply and an alternating-current power supply, and a control unit configured, in a case that the determination unit determines that the current time is in the nighttime, to maintain a switch in a closed state, the switch being provided between the power converter and one of the alternating-current power supply and the direct-current power supply, and to maintain power consumption by a resistor provided in a main circuit inside a housing of the power converter. The power conversion system can suppress lowering of temperature inside a housing without separately including a space heater.

Abstract: A control device for a power conversion apparatus that can prevent a rush current from flowing into a power converter. In a power conversion apparatus with a power converter connected with a DC power supply, a filter, and a switch connected with an AC power supply are connected in series in that order, a control device for the power conversion apparatus includes: a calculation unit configured to calculate, from a value of an AC current flowing between the power converter and the filter and impedance of the filter, an estimated value for AC power to be outputted by the power converter; and a control unit configured to control an action of the power converter in a state that the switch is open such that a difference between a target value for AC power and the estimated value falls within an allowable range set in advance.

Abstract: A DC power feeding device includes a power feed line connected to a DC load, a first DC/DC converter provided between a solar battery and the power feed line, and a second DC/DC converter provided between a battery and the power feed line. A first controller controls the first DC/DC converter such that maximum power tracking control of the solar battery is performed in a normal state of a commercial AC power source. The first controller controls the first DC/DC converter such that the solar battery outputs a power smaller than a load power in a power failure. A second controller controls the second DC/DC converter such that the battery is charged in the normal state of the commercial AC power source. The second controller controls the second DC/DC converter such that DC voltage on the power feed line attains a reference voltage in the power failure.

Abstract: A power conversion device include a switch for switching so as to output by selecting one of a command value the first DC voltage controller outputs or holds or the command value the second DC voltage controller outputs, a detector that detects the opening of the contactor and the recovery from voltage disturbance in the system on the AC side of the power conversion circuit, and a switching controller controls the switching of the switch so that selects and outputs the command value output by the second DC voltage controller when the detector detects the opening of the contactor, and selects and outputs the command value held by the first DC voltage controller when the detector detects the recovery from the voltage disturbance.

Abstract: A power conversion apparatus includes a plurality of power conversion units each including a power conversion module, the plurality of power conversion units being arranged at an interval in a lateral direction orthogonal to a vertical direction, and at least one support body that extends from one side toward the other side of the plurality of power conversion units in the lateral direction, on which the plurality of power conversion units are placed from above. The support body is formed from an insulating member.

Abstract: A power conversion device includes a power conversion module, a phase change material, a heat dissipation member, a cooling mechanism, and a controller. A semiconductor switching element and a freewheeling diode configure a power conversion circuit. The phase change material is provided on a principal plane of a casing. The heat dissipation member includes a heat dissipation surface. The heat dissipation surface is overlapped with the principal plane to sandwich the phase change material. The cooling mechanism cools the heat dissipation member. The controller generates a driving signal for driving the power conversion circuit and controls the cooling mechanism. The controller includes a predetermined heating operation. The heating operation may drive the power conversion circuit, in a state that the cooling mechanism is stopped or intermittently operated, such that heat generation occurs in both the semiconductor switching element and the freewheeling diode.

Abstract: An electrical power system includes: a solar battery panel; a first electrical power conversion device; a secondary battery; and a second electrical power conversion device. The first electrical power conversion device and the second electrical power conversion device selectively execute a first mode in which the first electrical power conversion device performs MPPT control on the solar battery panel and the second electrical power conversion device performs the charging-discharging control and a second mode in which the first electrical power conversion device performs output limit control to restrict output electrical power from exceeding a predetermined output limiter value and the second electrical power conversion device performs MPPT control on the solar battery panel.