Abstract: Each of a plurality of unit converters includes: a main circuit; a control circuit that controls the plurality of switching elements according to a control signal received from the controller; a power supply that lowers a voltage of a first capacitor to generate a power supply voltage and supplies the power supply voltage to the control circuit; and a current-limiting resistance circuit having a variable resistance value and disposed between the main circuit and the power supply. The power supply includes a second capacitor, an overcharge suppression circuit, a power supply circuit, and a controller. The controller includes: an overcharge suppression control circuit that controls the overcharge suppression circuit in accordance with a magnitude of a voltage of the second capacitor; and a resistance switching circuit that changes a resistance value of the current-limiting resistance circuit in accordance with a magnitude of a voltage of the first capacitor.

Abstract: A power supply includes a second capacitor, an overcharge suppression circuit, a power supply circuit, and a controller. The controller includes: an overcharge suppression control circuit that controls the overcharge suppression circuit in accordance with a magnitude of a voltage of the second capacitor; and a resistance switching circuit that changes a resistance value of the current-limiting resistance circuit depending on whether a gate block state occurs or not and in accordance with a magnitude of the voltage of the first capacitor. In the gate block state, each of the switching elements is fixed in a non-conductive state.

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 conditioner includes an inverter circuit that converts a DC voltage into an AC voltage, a voltage dividing circuit having one end connected to the positive electrode input terminal and the other end connected to the negative electrode input terminal, and a ground fault detector configured to receive a voltage divided by the voltage dividing circuit as an input voltage signal and to detect an occurrence of a ground fault based on the magnitude of the voltage of the input voltage signal. the ground fault detector emits an AC ground fault detection signal when the input voltage signal includes a first voltage signal having a frequency equal to or higher than a predetermined first frequency and a deviation of the first voltage signal with respect to an AC ground reference potential is equal to or larger than an AC ground fault detection voltage.

Abstract: In an endless rolling line, a speed of a material to be rolled changes with a flying thickness change. A temperature control device executes predictive calculation of a speed change amount of the material to be rolled associated with the flying thickness change and updates a speed pattern. The temperature control device executes feedforward control of an amount of a coolant to cool the material to be rolled based on a latest speed pattern and a measured temperature value of the material to be rolled in an entry side of the heat exchanger. In parallel with the feedforward control, the temperature control device executes feedback control of coolant volume based on an error between the measured temperature value of the material to be rolled in the delivery side of the heat exchanger and a target value.

Abstract: A DC/DC converter system includes a current sensor sensing a current flowing from a photovoltaic panel to a power converter device, and a DC/DC converter provided between a battery facility and the power converter device and configured to convert first DC power output from the battery facility into second DC power. The DC/DC converter includes a first operation mode in which the second DC power is generated to allow an output current and an output voltage to simulate the photovoltaic-cell current-voltage characteristics according to a current value sensed with the current sensor. The DC/DC converter may also include a second operation mode executing a boost operation of increasing a potential at a connection node, and a third operation mode in which a voltage at the connection node is converted to charge the battery facility. The DC/DC converter can selectively switch among the first, second, and third operation modes.

Abstract: A power system includes a photovoltaic cell panel, a first power conversion device converting the DC power from the photovoltaic cell panel into AC power, and outputting the AC power to an electric power grid, a DC-side switch device provided between the photovoltaic cell panel and the first power conversion device and opening upon a trouble, a storage battery, and a second power conversion device connected to a connection point between the photovoltaic cell panel and the DC-side switch device and controlling charging and discharging of the storage battery. The second power conversion device includes a normal charging control mode for charging the storage battery based on a command signal from the system host monitor. Disconnection charging control mode may be executed when the DC voltage of the connection point exceeds a predetermined threshold value even if the command signal does not instructs the normal charging control mode.

Abstract: A coupling member includes: first, second, and third portions each having a flat plate-like shape; and a fillet portion. The first portion has a first side and a second side orthogonal to each other. The second portion is bent at the first side relative to the first portion, and extends to an inner surface of the first portion. The third portion is bent at the second side relative to the first portion, and extends to an inner surface of the first portion. A bend radius of an outer surface of the coupling member at the first side is equal to a bend radius of a surface of a first extending member facing the first side. A bend radius of an outer surface of the coupling member at the second side is equal to a bend radius of a surface of a second extending member facing the second side.

Abstract: A power supply system includes: a semiconductor switch (1) that is turned on at the time of normal supply from a commercial AC power supply (5); a first current detector (CT1) including a transformer (10) and configured to detect an AC input current (I1); a second current detector (CT2) including a Hall effect sensor (20) and configured to detect an AC output current (I2); and a failure detector (30) that determines that one of a pair of thyristors (1a, 1b) included in the semiconductor switch (1) has misfired when the detection values from the first and second current detectors (CT1, CT2) are not equal at the time of normal supply from the commercial AC power supply (5).

Abstract: A system including a controller that continuously receives a SOC correlation value of a battery. The controller transmits an open/close signal of a first pattern to a plurality of switches during a period in which a stand-alone operation is being executed and the SOC correlation value is higher than a first threshold value. The controller transmits an open/close signal of a second pattern to the plurality of switches during a period in which the stand-alone operation is being executed and the SOC correlation value is equal to or lower than the first threshold value and higher than a second threshold value that is lower than the first threshold value. The number of load connections according to the open/close signal of the second pattern is fewer than the number of load connections according to the open/close signal of the first pattern and is equal to or more than 1.

Abstract: An AC switch (1) includes a first thyristor (T1), a second thyristor (T2), a third thyristor (T3), and a fourth thyristor (T4). The first thyristor (T1) has an anode connected to an AC power source (2), and a cathode connected to a load (3). The second thyristor (T2) is connected in antiparallel to the first thyristor (T1). The third thyristor (T3) has an anode connected to the AC power source (2), and a cathode connected to the load (3). The fourth thyristor (T4) is connected in antiparallel to the third thyristor (T3). A current detector (5) detects the AC current supplied from the AC power source (2) to the load (3). A controller (6) causes the first thyristor (T1) and the third thyristor (T3) to conduct alternately and causes the second thyristor (T2) and the fourth thyristor (T4) to conduct alternately, for each one-cycle period of the AC current, in accordance with the detection value from the current detector (5).

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 power conversion device, including: a voltage detector that detects a common mode voltage generated upon a switching operation of a power semiconductor device; a voltage superimposer that superimposes the common mode voltage detected by the voltage detector onto an output of the power conversion device to cancel the common mode voltage having a frequency greater than or equal to a switching frequency generated upon the switching operation of the power semiconductor device; and a residual voltage detector that detects the common mode voltage of the power conversion device superimposed by the voltage superimposer. The voltage superimposer includes a feedback mechanism for adding and superimposing the common mode voltage detected by the residual voltage detector onto the output of the power conversion device. The voltage detector includes a first choke coil and a first capacitor.

Abstract: A cooling device according to an embodiment includes a first heat exchanger, a first pipe, a second pipe, a bypass pipe, a flow changing mechanism, and a controller. The controller is configured to monitor a detection value related to at least one of a power loss of an electric device and the temperature of a first cooling water, configured to control the flow changing mechanism so that the quantity of a second cooling water flowing from the second pipe into the bypass pipe increases in a case where the detection value is smaller than a first threshold, and configured to control the flow changing mechanism so that the quantity of the second cooling water flowing from the second pipe into the bypass pipe decreases in a case where the detection value is equal to or larger than a second threshold.

Abstract: A power conversion device capable of suppressing air from flowing back into a housing is provided. The power conversion device includes a power conversion unit configured to perform power conversion, a housing for accommodating the power conversion and having an air inlet and an air outlet, a fan provided inside the housing and generating airflow in such a manner that air flows to the outside of the housing via the air outlet after flowing into the housing via the air inlet, and a cover provided at the air outlet, the cover being configured to be brought into an opened state with respect to the air outlet if the airflow generated by the fan is stronger than airflow moving from the outside of the housing toward the air outlet, and to be brought into a closed state with respect to the air outlet if the airflow generated by the fan is weaker than the airflow moving from the outside of the housing toward the exhaust of the housing.

Abstract: According to an embodiment of the invention, a control device is provided and controls a power converter that can be connected to a terminal of a direct current power transmission system transmitting power according to a current command value that is set. The control device includes a first characteristic setter having a first characteristic preset. When the power converter is set at a power transmission end of the direct current power transmission system, the first characteristic outputs an output terminal voltage for the power converter. The output terminal voltage corresponds to a current of a current control based on a current command value set at a power receiving end of the direct current power transmission system. The output terminal voltage of the first characteristic monotonously decreasing with respect to the current of the current control.

Abstract: This uninterruptible power supply includes: a cooler (6) that dissipates heat of a converter (1) and an inverter (5); and a controller (8) that causes, when output power (Po) from the inverter (5) exceeds an upper limit value (PoH), reduces input power (Pi) to the converter (1) by power (?Po=Po?PoH) corresponding to a difference between them, and increases input power (Pb) to a bidirectional chopper (4) by power (2×PoH) that is twice as high as the power (?Po) corresponding to the difference.

Abstract: A gas passing groove, a high-voltage electrode groove, and a ground electrode groove provided to an electrode unit base are each helical in plan view. An electrode unit lid is placed on a front surface of the electrode unit base so that a high-voltage conduction hole and a high-voltage conduction point coincide with each other in plan view. An electrode cooling plate is placed on a front surface of the electrode unit lid so that a high-voltage opening includes the high-voltage conduction hole as a whole in plan view. The electrode unit lid and the electrode cooling plate are placed on the front surface of the electrode unit base so that a ground conduction groove, a ground conduction hole, and a ground conduction point coincide with one another in plan view.

Abstract: A film forming device includes a bottom plate detachably provided on a bottom surface of a mist spray head. The bottom plate includes a raw material solution opening, reaction material openings, and inert gas openings formed in regions corresponding to a raw material solution ejection port, reaction material ejection ports, and inert gas ejection ports, when the bottom plate is attached to the bottom surface of the mist spray head.

Abstract: A data collection system includes sensors which are synchronized with each other and an optical signal distributor, wherein each of the sensors comprises a first delay unit which delays a second electrical signal for a first delay time set such that a sum of the first delay time and a first conversion time is same in all of the sensors, and the optical signal distributor comprises second delay units each of which delays a first electrical signal for a second delay time set such that all of sums of the second delay times and conversion times are same as each other.