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 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: 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: This invention is intended to provide a wind power generator system or method for controlling a wind power generator system, designed to implement switching-initiated smooth energy changeover without leading to a complex system configuration. The method of controlling a wind power generator system according to an aspect of the invention, wherein the generator system includes a wind turbine that uses wind to generate electric power and a control device that controls the wind turbine, is a control method designed so that when the wind turbine is generating power, the turbine drives the control device by use of the turbine-generated power, irrespective of an electric power system state.

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: An object of the present invention is to provide a Wind Turbine Generation System that eliminates the necessity of switching to a circuit different from the one used during a normal power generation operation even when Power grid voltage sags.

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 commanded negative-sequence current is added to a commanded current so as to suppress double-frequency pulsation on the DC side. The commanded negative-sequence current is found from three values (i.e., the detected value of positive-sequence voltage vector on the power-supply side, the detected value of negative-sequence voltage vector, and a commanded positive-sequence current). Thus, the pulsations which occur on the DC side of a semiconductor power converter and which have a frequency double the power-supply frequency are suppressed even when the AC power supply is at fault while assuring stability of the current control system, thus permitting stable and continuous operation.

Abstract: The invention provides a power converter including a plurality of power conversion units each connected to a different feeder, a DC energy interchange unit connected to the power conversion units and connected to a secondary battery, and a power control unit which instructs the regeneration-side power conversion unit connected to the regeneration-side feeder of the feeders, through which a regenerative current flows, and the consumption-side power conversion unit connected to the consumption-side feeder through which a current consumption flows, to output power from the regeneration-side feeder to the consumption-side feeder through the DC energy interchange unit. The power control unit also determines the voltage of the DC energy interchange unit in such a manner as to input/output energy corresponding to the sum of regenerative power of the regeneration-side feeder and consumed power of the consumption-side feeder to and from the secondary battery.

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: In the present invention, provided is a power conversion apparatus in which at least one energy storage element and at least one switching element are included, a plurality of series circuits of a transformer winding and an arm in which one or a plurality of at least two-terminal unit converters which depend on ON/OFF of the switching element and supply a zero voltage or a voltage depending on a voltage of the energy storage element are connected in series are connected in parallel, and a multi-phase power source or a multi-phase load is connected to another winding of the transformer, and the parallel-connection point is set as a DC terminal, and which includes means for controlling a current flowing through each of the arms to have a phase and amplitude different from each other.

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 capacitors. Each of the legs has a first terminal on a positive side and a second terminal on a negative side. The control apparatus is operative to create command pulses for operating the converter modules to operate the converter modules. The command pulses have a frequency that is a non-integral multiple of a frequency of a system voltage. The non-integral multiple is 3.5, for example.

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 wind power generating system includes a unit for eliminating harmonics component of specified-order from inputted current detection value of a grid-side converter and a unit for controlling the grid-side converter using the current detection value in which harmonics are eliminated.

Abstract: The disclosed windfarm control system comprising a windfarm and a central controller; the windfarm including plural wind power generators whose rotational speeds are variable, plural aerographs disposed in the vicinity of the wind power generators to measure the directions and powers of the wind at the sites of the generators, and plural local controllers disposed in the vicinity of the wind power generators to control the output of the wind power generators by controlling the rotational speeds of the generators; wherein the central controller calculats the control level which maintains the output of the windfarm constant for a predetermined time period and instructs the local controllers to control the rpm's of the wind power generators in accordance with the control level.

Abstract: A wind turbine generator system can regulate the rotational velocity of the wind turbine within an operation range even when the wind velocity suddenly changes and can perform continuous operation of the wind turbine. The wind turbine generator system includes a generator connected to the shaft of the wind turbine and a converter connected to the generator. When the rotational velocity of the wind turbine is within a predetermined range, power outputted from the generator is controlled so as to follow the instruction concerning the generator output given from the wind turbine to the converter. When the rotational velocity of the wind turbine is out of the predetermined range, the power outputted from the generator is controlled without following the instruction concerning generator output given from the wind turbine to the converter.

Abstract: This invention is intended to provide a wind power generator system or method for controlling a wind power generator system, designed to implement switching-initiated smooth energy changeover without leading to a complex system configuration. The method of controlling a wind power generator system according to an aspect of the invention, wherein the generator system includes a wind turbine that uses wind to generate electric power and a control device that controls the wind turbine, is a control method designed so that when the wind turbine is generating power, the turbine drives the control device by use of the turbine-generated power, irrespective of an electric power system state.

Abstract: In a controller for a windfarm including a plurality of wind turbine generators controllable in rotation frequency and pith of blades of the wind turbine generators, coupled to a grid through a transmission line, an anemometer is provided to each wind turbine generator to transmits wind direction and wind speed data to a central controller which process the wind direction and wind speed data to transmit an output command each wind turbine generator. The central controller predicts, on the basis of the wind speed detected by the upstream wind turbine generator, variation in wind speed at other wind turbine generators to control the output of the windfarm. The output power may be limited or charging energy as rotation energy of blades and discharging the rotation energy as output power in addition to a battery unit for averaging.