Abstract: A secondary magnetic excitation generator-motor device that inputs a first ignition pulse command to a three-level NPC power converter such that a detected excitation current value corresponds with an excitation current command value, the secondary magnetic excitation generator-motor device having a function of identifying a first phase, a second phase, or a third phase in descending order of a current absolute value, wherein a pulse switch to output an ignition pulse command to the three-level NPC power converter switches the ignition pulse command to the second ignition pulse command when a current absolute value exceeds a set overcurrent level 1, and switches the ignition pulse command to the first ignition pulse command when current absolute values for three phases are all equal to or smaller than a set overcurrent level 2.

Abstract: A modular multilevel power converter includes: a capacitor voltage adjuster that calculates an active current component command to make an average voltage of capacitors match a command value; an active power detector that receives an AC current signal and an AC voltage signal and calculates an active power; an active power adjuster that calculates a DC current command value to make the active power match a command value; a first active power command suppressor that suppresses an absolute value of an active power command value; and a second active power command suppressor that adjusts an absolute value of an active power command value.

Abstract: A secondary magnetic excitation generator-motor device that inputs a first ignition pulse command to a three-level NPC power converter such that a detected excitation current value corresponds with an excitation current command value, the secondary magnetic excitation generator-motor device having a function of identifying a first phase, a second phase, or a third phase in descending order of a current absolute value, wherein a pulse switch to output an ignition pulse command to the three-level NPC power converter switches the ignition pulse command to the second ignition pulse command when a current absolute value exceeds a set overcurrent level 1, and switches the ignition pulse command to the first ignition pulse command when current absolute values for three phases are all equal to or smaller than a set overcurrent level 2.

Abstract: In a variable speed generator/motor device including a variable frequency power converter, a direct current voltage device including a voltage type self-excited converter, an automatic voltage adjuster, and a converter current adjuster that controls unit converters, a first three-phase branch circuit is provided between the direct current voltage device and an alternating current system; a second three-phase branch circuit is provided between the variable frequency power converter and a three-phase alternating current synchronous machine; a first load switch is provided between the first three-phase branch circuit and the second three-phase branch circuit; a measurement current transformer is provided between the three-phase alternating current synchronous machine and the second three-phase branch circuit; when switching from a converter mode in which the variable frequency power converter drives the three-phase alternating current synchronous machine to generate power to a bypass mode, the first load switch

Abstract: A method for producing a SiC epitaxial wafer according to the present embodiment includes: an epitaxial growth step of growing the epitaxial layer on the SiC single crystal substrate by feeding an Si-based raw material gas, a C-based raw material gas, and a gas including a Cl element to a surface of a SiC single crystal substrate, in which the epitaxial growth step is performed under growth conditions that a film deposition pressure is 30 torr or less, a Cl/Si ratio is in a range of 8 to 12, a C/Si ratio is in a range of 0.8 to 1.2, and a growth rate is 50 ?m/h or more from an initial growth stage.

Abstract: In a variable speed generator/motor device including a variable frequency power converter, a direct current voltage device including a voltage type self-excited converter, an automatic voltage adjuster, and a converter current adjuster that controls unit converters, a first three-phase branch circuit is provided between the direct current voltage device and an alternating current system; a second three-phase branch circuit is provided between the variable frequency power converter and a three-phase alternating current synchronous machine; a first load switch is provided between the first three-phase branch circuit and the second three-phase branch circuit; a measurement current transformer is provided between the three-phase alternating current synchronous machine and the second three-phase branch circuit; when switching from a converter mode in which the variable frequency power converter drives the three-phase alternating current synchronous machine to generate power to a bypass mode, the first load switch

Abstract: In a variable speed generator/motor device including a variable frequency power converter, a direct current voltage device including a voltage type self-excited converter, an automatic voltage adjuster, and a converter current adjuster that controls unit converters, a first three-phase branch circuit is provided between the direct current voltage device and an alternating current system; a second three-phase branch circuit is provided between the variable frequency power converter and a three-phase squirrel-cage induction machine; a first load switch is provided between the first three-phase branch circuit and the second three-phase branch circuit; a measurement current transformer is provided between the three-phase squirrel-cage induction machine and the second three-phase branch circuit.

Abstract: In a variable speed generator-motor apparatus, a power converter includes six two-terminal arms each formed by serially connecting k unit converters that can output arbitrary voltage, an AC rotating electric machine includes an armature winding with 60-degree phase zone formed from a double layer coil, the armature winding being divided into first and second pole sides to form double star connection by binding neutral points and to be drawn out as two sets of three-phase terminals; three-phase terminals on the first pole side are connected to first terminals of three arms, and second terminals of the three arms are star-connected to a first terminal of a DC power supply; three-phase terminals on the second pole side are connected to second terminals of remaining three arms, and first terminals of the three arms are star-connected to a second terminal of the DC power supply.

Abstract: In a variable speed generator-motor apparatus, a power converter includes six two-terminal arms each formed by serially connecting k unit converters that can output arbitrary voltage, an AC rotating electric machine includes an armature winding with 60-degree phase zone formed from a double layer coil, the armature winding being divided into first and second pole sides to form double star connection by binding neutral points and to be drawn out as two sets of three-phase terminals; three-phase terminals on the first pole side are connected to first terminals of three arms, and second terminals of the three arms are star-connected to a first terminal of a DC power supply; three-phase terminals on the second pole side are connected to second terminals of remaining three arms, and first terminals of the three arms are star-connected to a second terminal of the DC power supply.

Abstract: A method for producing a SiC epitaxial wafer according to the present embodiment includes: an epitaxial growth step of growing the epitaxial layer on the SiC single crystal substrate by feeding an Si-based raw material gas, a C-based raw material gas, and a gas including a Cl element to a surface of a SiC single crystal substrate, in which the epitaxial growth step is performed under growth conditions that a film deposition pressure is 30 torr or less, a Cl/Si ratio is in a range of 8 to 12, a C/Si ratio is in a range of 0.8 to 1.2, and a growth rate is 50 ?m/h or more from an initial growth stage.

Abstract: In a variable speed generator-motor apparatus, a power converter includes six two-terminal arms each formed by serially connecting k unit converters that can output arbitrary voltage, an AC rotating electric machine includes an armature winding with 60-degree phase zone formed from a double layer coil, the armature winding being divided into first and second pole sides to form double star connection by binding neutral points and to be drawn out as two sets of three-phase terminals; three-phase terminals on the first pole side are connected to first terminals of three arms, and second terminals of the three arms are star-connected to a first terminal of a DC power supply; three-phase terminals on the second pole side are connected to second terminals of remaining three arms, and first terminals of the three arms are star-connected to a second terminal of the DC power supply.

Abstract: This SiC epitaxial wafer includes: a SiC single crystal substrate of which a main surface has an off-angle of 0.4° to 5° with respect to (0001) plane; and an epitaxial layer provided on the SiC single crystal substrate, wherein the epitaxial layer has a basal plane dislocation density of 0.1 pieces/cm2 or less that is a density of basal plane dislocations extending from the SiC single crystal substrate to an outer surface and an intrinsic 3C triangular defect density of 0.1 pieces/cm2 or less.

Abstract: This gas piping system is a run-vent mode gas piping system in which, the gas piping system including a plurality of supply lines through which plural gases are fed individually, an exhaust line that leads from a reactor to an exhaust pump, a run line having one or plural pipes which respectively branch from the plural supply lines, plural vent lines which respectively branch from the supply lines and are connected to the exhaust line, and plural valves which are respectively provided at the branch points of the plural supply lines, and switches between feeding a gas to the run line side and feeding a gas to the vent line side, wherein the plural vent lines are separated from each other until the vent lines reach the exhaust line, and the inner diameter of the exhaust line is greater than the inner diameter of the plural vent lines.

Abstract: In a variable speed generator-motor apparatus, a power converter includes six two-terminal arms each formed by serially connecting k unit converters that can output arbitrary voltage, an AC rotating electric machine includes an armature winding with 60-degree phase zone formed from a double layer coil, the armature winding being divided into first and second pole sides to form double star connection by binding neutral points and to be drawn out as two sets of three-phase terminals; three-phase terminals on the first pole side are connected to first terminals of three arms, and second terminals of the three arms are star-connected to a first terminal of a DC power supply; three-phase terminals on the second pole side are connected to second terminals of remaining three arms, and first terminals of the three arms are star-connected to a second terminal of the DC power supply.

Abstract: Feeder sections to be a target of interchange are to be expanded in order to improve the effect of power interchange between feeders. A control device for railway power conditioner is connected to a first feeder connected to a load side of a transformer in a first railway substation including a transformer receiving power from a power grid, and a second feeder connected to a load side of a transformer in a second railway substation including a transformer receiving power from a power grid, and decides an amount of power interchanged between the first and second feeders. The control device decides the amount of power interchanged between the first and second feeders, using the received power in the first railway substation and power on the first feeder, and the received power in the second railway substation and power on the second feeder.

Abstract: A switching element of a power converter generates a low voltage, using a current flowing in the power converter, and supplies a power to drive itself. A switching element of a power converter for conversion from direct current into alternate current or from alternate current into direct current includes: a terminal and a terminal which are used in building the switching element itself in the power converter; a capacitor, a high-side controllable switch and a low-side controllable switch enabling outputting the voltage of the capacitor, the voltage being output between the terminal and the terminal, and a self-supply power source for supplying a power to drive the bi-directional chopper switching element itself, using a current flowing in the capacitor.

Abstract: The present invention provides a duplexed operation processor control system that includes operation processors, an I/O device, and at least one communication path that couples the operation processors to the I/O device, and at least one communication path that couples the operation processors with each other. The duplexed operation processor control system switches over either of the operation processors to be a primary operation processor that executes a control operation for a control target, and the other to be a secondary operation processor that is in a stand-by state, and the secondary operation processor snoops control data synchronously when the primary operation processor acquires the control data from the control target.

Abstract: A control apparatus for use with a voltage source converter includes legs, each of which is configured by a plurality of converter modules each having a capacitor. Each of the legs has a first terminal on a positive side and a second terminal on a negative side. The control apparatus is configured to create command pulses for operating the converter modules. The command pulses have a frequency that is a non-integer multiple of a frequency of a system voltage. The non-integer multiple may be, for example, 3.5.

Abstract: The excitation overcurrent detection unit for the doubly-fed electric machine is provided with a function to determine an excitation current magnitude relationship among three phases. The firing pulse is held to on-state or off-state to cause the largest-current phase and the second-largest-current phase to charge the DC capacitor by the operation of diodes. The conduction ratio of the third-largest-current phase or minimum current phase is controlled according to the detected current value to protect against a possible short-circuit across the DC capacitor. When the voltage of the DC capacitor exceeds a preset value, the voltage is suppressed by operating active or passive power devices.

Abstract: A substrate is formed of AlxGa1-xN, wherein 0<x?1. The substrate is a single crystal and is used producing a Group III nitride semiconductor device. A method for producing a substrate of AlxGa1-xN, wherein 0<x?1, includes the steps of forming a layer of AlxGa1-xN, wherein 0<x?1, on a base material and removing the base material. The method adopts the MOCVD method using a raw material molar ratio of a Group V element to Group III element that is 1000 or less, a temperature of 1200° C. or more for forming the layer of AlxGa1-xN, wherein 0<x?1. The base material is formed of one member selected from the group consisting of sapphire, SiC, Si, ZnO and Ga2O3. The substrate is used for fabricating a Group III nitride semiconductor device.