Hitachi, Ltd.

Hitachi Mitsubishi Hydro Corporation

Hitachi Industrial Products, Ltd.

Hitachi Power Solutions Co., Ltd.

Tomomichi Ito

Shuji Katoh

Takashi Ikimi

Shigeta Ueda

Hiromitsu Sakai

Noriaki Hino

Naohiro Kusumi

Kazuo Takahashi

Akira Bando

Yasuhiro Kiyofuji

Masaya Ichinose

Masakazu Ishikawa

Tetsuya Kato

Kenta Watanabe

Nobuhiro Kusuno

Takahiko Kikui

Masahiro Watanabe

Motoo Futami

Mamoru Kimura

Toru Yoshihara

Akira Kikuchi

Akiyoshi Komura

Yusuke Abe

Daisuke Kori

Motonobu Iizuka

Tetsuo Fujigaki

Shigenori Inoue

Hironari Kawazoe

Chikara Tanaka

Tetsuro Morisaki

Hidetoshi Aizawa

Masahiro Taniguchi

Yoshio Eguchi

Takayoshi Yamamoto

Hikaru Meguro

Osamu Sakuchi

Shoichiro Koseki

Aung Kothet

Keiichi Yamashita

Yosuke Nakaide

Jun Narushima

Kazuhide Tanaka

Takashi Matsuo

There is provided an adjustable speed generator motor system with full power converter (FPC system) in which two 3-level converters are connected back-to-back on the DC side, and by providing a mode in which a fly-wheeling diode is forced to conduct a current independently for three phases according to the current polarity and a mode in which the fly-wheeling diode is forced to conduct a current independently for three phases according to magnitude relation of the absolute value of a 3-phase AC current and the current polarity of each phase the FPC system is capable of continuing stable operation.

Adjustable speed generator motor system with full power converter

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.

Modular multilevel power converter and variable speed generator-motor

Providing a power system and a method for stabilizing a system, in which the number of generators to be disconnected is reduced to narrow an area influenced by a grid fault in the case where the reliability of the state estimation calculation is judged to be high. The power system stabilizing method applied to a power system configured to include a plurality of feeders including circuit breakers, a plurality of nodes, a plurality of generators, and a plurality of loads, in which method: a protection relay detects a grid fault by using an output from a first sensor installed close to the circuit breaker, thereby opening-controlling the circuit breaker, and the circuit breaker is opening-controlled by a power system stabilization output; a state estimation value of a power system obtained by using the first sensor output and a state detection value, of the power system, containing information associated with measurement time measured in the power system are compared with each other to judge reliability of the state estimation value; the circuit breaker which is to be newly cut off from a viewpoint of power system stability after occurrence of a grid fault at a supposed grid fault point of the power system is stored, and the circuit breaker which is to be cut off every reliability judgment result of the state estimation value is stored; and at the time of occurrence of a grid fault of the power system, a turn-off command for the circuit breaker which is selected in response to the reliability judgment result of the state estimation value so as to be newly cut off is set as the power system stabilization output.

System and method for stabilizing power system

A two-shaft gas turbine having high operability is provided. The two-shaft gas turbine includes: a gas generator having a compressor, a combustor and a high pressure turbine; a power turbine having a low pressure turbine; a load connected to the power turbine; a motor/generator capable of rotatably driving the gas generator and capable of extracting power from the gas generator; electric equipment controlling the rotational driving and the power extraction by delivering electric power between the electric equipment and the motor/generator; and a control device controlling the electric equipment, wherein the combustor has a plurality of combustion regions to which a fuel is supplied through fuel adjustment means which are independent from each other, and the control device controls a delivery amount of the electric power delivered by the electric equipment corresponding to the number of combustion regions to which the fuel is supplied.

Two-shaft gas turbine

The dual-shaft gas turbine power generation system includes: a high-pressure gas turbine; a first rotating shaft connecting a compressor and the high-pressure gas turbine; an electric motor connected to the first rotating shaft; a governor which adjusts the amount of air taken into the compressor; a low-pressure gas turbine; a second rotating shaft connected to the low-pressure gas turbine; a synchronous power generator connected to the second rotating shaft; a frequency converter which converts the frequency of power transmitted between the synchronous power generator and the electric motor; and a control device which controls a frequency converter control device for controlling the frequency converter, and the governor, on the basis of a power output command value indicating the power to be outputted to an external grid.

Dual-shaft gas turbine power generation system, and control device and control method for gas turbine system

A power converter with a simple configuration capable of controlling a rush current is provided. The power converter is installed between an electric power system and a power storage device, includes a harmonic filter in an AC circuit on the electric power system side and a DC capacitor and a DC breaker in a DC circuit on the power storage device side, and performs AC/DC conversion processing using an inverter. The power converter is configured in such a way that, when the power storage device starts running, a current limited by a limiting resistor is given from the electric power system side to the DC capacitor, the difference between the voltage of the DC capacitor and the voltage of the power storage device is monitored, and the power converter is connected to the power storage device by switching on the DC breaker on the basis of the difference.

Power converter installed between an electric power system and an energy storage device

A rotary machine includes two sets of three-phase stator winding wires and two sets of inverters connected to the same direct-current power supply. Alternating-current terminals of the inverters are respectively connected to the three-phase stator winding wires. Stator winding wires are housed in a plurality of slots to form a stator. The two sets of three-phase stator winding wires and the stator winding wires in the same phase of the sets are started to be wound from the slot positions, with phases thereof being different from each other by 180 degrees, among the plurality of slots and are finished being wound in the slot positions, with phases thereof different from each other by 180 degrees. Winding end points of the three-phase stator winding wires are respectively connected in common, and alternating-current voltages having the same magnitude and opposite phases are applied to the two sets of three-phase stator winding wire.

Rotary machine and drive system therefor

An electrical rotating machine system that can be easily maintained and can provide improved power generation efficiency. The electrical rotating machine system includes: a first electrical rotating machine having a first stator that has first stator windings, and a first rotor that has first rotor windings and is disposed on the internal diameter side of the first stator so as to have a gap between the internal diameter side of the first stator and the first rotor itself; a second electrical rotating machine having a second stator that has second stator windings, and a second rotor that has second rotor windings and is disposed on the internal diameter side of the second stator so as to have a gap between the internal diameter side of the second stator and the second rotor itself; and at least one power converter that is electrically connected to the first rotor windings and the second rotor windings, and configured to rotate when the first rotor rotates.

Electrical rotating machine system or wind turbine system

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.

Switching element, power converter, direct current transmission system, current control device, method of controlling power converter, and method of controlling current in voltage source converter

An energy saving type feeder voltage compensation apparatus improved in availability at low temperatures, wherein when a electric energy storage apparatus is lower in temperature than a predetermined value, an output voltage output to a feeder side is made equal to or higher than a no-load output voltage of a substation connected in parallel. Power is supplied to a power running rolling stock preferentially from the electric energy storage apparatus. The heating value of the secondary battery is increased and the battery temperature is raised by this discharging, whereby internal resistance of the electric energy storage apparatus is lowered, and the charging and discharging loss is suppressed, and the efficiency and availability of the energy saving type feeder voltage compensation apparatus as a whole are improved.

Energy storage type feeder voltage compensation apparatus and method of controlling feeder voltage

In a system to which a fluctuating load is connected, compensating for fluctuation in voltage harmonics at the load connecting point and fluctuation in system current harmonics has been difficult for a power converting device connected in parallel with the load. To resolve the problem, a power converting device connected in parallel with a fluctuating load includes: a Fourier series expansion unit which executes Fourier series expansion to load current by use of a reference sine wave in sync with a system and thereby outputs Fourier coefficients; and a fundamental component calculating unit which calculates a positive phase active fundamental component of the load current from the Fourier coefficients. A current instruction of the power converting device is generated by subtracting the fundamental current from the load current. With the current instruction, the fluctuations in system current harmonics and in voltage harmonics at the connecting point can be compensated for.

Power converting device and method for controlling the same

An energy saving type feeder voltage compensation apparatus improved in availability at low temperatures, wherein when a secondary battery is lower in temperature than a predetermined value, an output voltage output to a feeder side is made equal to or higher than a no-load output voltage of a substation connected in parallel. Power is supplied to a power running rolling stock preferentially from the secondary battery. The heating value of the secondary battery is increased and the battery temperature is raised by this discharging, whereby internal resistance of the secondary battery is lowered, and the charging and discharging loss is suppressed, and the efficiency and availability of the energy saving type feeder voltage compensation apparatus as a whole are improved.

A semiconductor power converting apparatus including at least one series arrangement of MOS control semiconductor devices such as Insulator-gate Bipolar Transistors (IGBTs) or metal oxide MOS transistors which are respectively applied with a gate voltage under the control of corresponding a driver. The driver contains a supply line having a higher potential than a gate voltage of an IGBT coupled thereto when the IGBT is in a steady ON state, and is such that is causes an increase of the gate voltage of the IGBT in accordance with the current of the supply line when a potential difference between the power supply line and an emitter of the IGBT is constant and the collector voltage thereof exceeds a predetermined value under an ON state of the IGBT.

Semiconductor power converting apparatus

A power conversion apparatus has a circuit configuration in which a collector voltage of an IGBT is divided. It also has a unit which protects the IGBT against overvoltages applied to the collector by outputting a potential of a voltage dividing point to a gate of the IGBT. A case of a resistor on the high-voltage side of the voltage dividing point is fixed to an emitter potential of the IGBT.

Semiconductor power conversion apparatus

Growing community of inventors

Hitachi, Japan

Tomomichi Ito