Hitachi, Ltd.

Shigenori Inoue

Shuji Katoh

Tetsuya Kato

Toru Yoshihara

Jun Narushima

Masaya Ichinose

Akira Bando

Takayoshi Yamamoto

Hiroyuki Fujita

Osamu Tomobe

Tomomichi Ito

Yasuhiro Kiyofuji

Shinya Oohara

Hironari Kawazoe

Mitsuyoshi Tsuchiya

Hideki Ogata

Kenta Watanabe

Tadashi Sodeyama

Yoshio Eguchi

Osamu Sakuchi

Makoto Kadowaki

Tohru Yoshihara

Efrain Eduardo Tamayo Ruiz

Yoichiro Yamada

Keiichi Yamashita

Conventionally, optimum introduction assistance for devices including a FACTS device and a storage adapted to changes in impedance and a transmission capacity involved in an increase of renewable energy power supplies has not been achieved. Therefore, in order to solve the problem, the present invention provides a power system equipment introduction assistance device that calculates an introduction point of power system equipment coupled to a power system, the introduction assistance device including a calculating unit configured to calculate, on the basis of predetermined system information and information concerning the power system equipment scheduled to be introduced, a characteristic of the power system affecting the power system during the introduction of the power system equipment and calculate the introduction point of the power system equipment from a predetermined evaluation index related to the characteristic of the power system.

Power system equipment introduction assistance device and method

A power conversion device is provided which includes a plurality of series circuits each formed of a voltage source and a controlled current source. At least two of said series circuits formed of the voltage source and the controlled current source are connected in parallel. Further, parallel connection points of the series circuits connected in parallel form output terminals.

Power conversion device with a plurality of series circuits

A power conversion apparatus includes arms in each of which one or more unit converters each including a capacitor and capable of outputting an arbitrary voltage are connected in series, and a point P as a first node to which one end of the respective arms are Y-connected, and a point N as a second node to which a neutral terminal of the rotary electric machine is connected. The other end of the respective arms are connected to one ends of respective phase windings of a rotary electric machine.

Power conversion apparatus and electrical-mechanical energy conversion system

A power conversion apparatus including a three-phase transformer having at least four three-phase windings, and three converter arms each configured by connecting one or plural unit converters each including a switching device and an energy storage element in series. A power source or a load is connected to a first three-phase winding of the transformer, three series circuits which connects second and third three-phase windings of the transformer, and the converter arms in series with each other are connected in parallel, the parallel connection point is a DC terminal, and a magnitude relationship between a coupling coefficient of the first and second three-phase windings, and a coupling coefficient of the first three- and third three-phase windings is equal to a magnitude relationship between a coupling coefficient of the fourth and second three-phase windings, and a coupling coefficient of the fourth and the third three-phase windings.

Power conversion apparatus and high-voltage DC transmission 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

A power conversion device includes: a plurality of cascade-connection type single-phase power converters; and a central control unit that controls the plurality of the single-phase power converters, wherein each of the plurality of single-phase power converters has a single-phase power converter control unit, and the central control unit and the plurality of the single-phase power converter control units are connected via a communication means having a daisy-chain configuration, wherein the single-phase power converter control unit transmits and receives a control signal via the communication means having the daisy-chain configuration, as well as a specific pattern signal, other than a control signal frame, which can be distinguished from the control signal frame, and determines a communication error due to not receiving the specific pattern signal at the single-phase power converter control unit, or an inconsistency between the received signal and the specific pattern signal.

Power conversion device with a daisy chain configuration communication control unit

A power conversion device includes at least two legs connected in parallel each of which includes at least two unit converters connected in series, wherein at least one of the legs is formed using at least two kinds of unit converters including a first type unit converter capable of outputting a unipolar voltage and a second type unit converter capable of outputting a bipolar voltage.

Power conversion device including a plurality of legs connected in parallel, each leg including a plurality of unit converters connected in series

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.

Multilevel voltage source converter and method for balancing capacitors

Disclosed is a power conversion device, wherein among the optical fiber cables used in control/communication, at least the majority of high-voltage optical fiber cables with a dielectric strength against the output voltages of a plurality of cells can be eliminated and thus a low-voltage optical fiber cable with a dielectric strength against the output voltage of one cell can be used. Furthermore, here, the length required for the optical fiber cable can be reduced. A controller of the power conversion device comprising a plurality of cascade-connected cells comprises a central controller, and a cell controller with the same potential as each cell, the cell controller being installed in the vicinity of each cell, wherein the central controller and each cell controller are daisy-chained using an optical fiber cable.

Power converter with a central controller and cell controllers daisy-chained by optical fiber

A power conversion device connected with a three-phase power system through a transformer, including unit converters cascade-connected so that reactors are unnecessary, and volume and weight are reduced. The secondary winding of the transformer is an open winding having six terminals. A first converter group, includes a circuit which has three converter arms, which are star-connected, connected to three of the terminals of the secondary winding. A second converter group, having three different converter arms which are star-connected, is connected to three other terminals of the secondary winding. A neutral point (the point where the star connection is made) of the first converter group, and a neutral point of the second converter group are made to be the output terminals of the power conversion device.

Power conversion device

The noise generated from a power converter is suppressed by increasing the noise frequency to a level not lower than the maximum frequency of the human audible range. To obtain the frequency of an output current harmonic component as a noise source which has exceeded the maximum frequency of the human audible range, it is adequate to determine that the frequency of a driving carrier wave for the individual converter cells in the power converter, in which the phases of the carrier wave for the converter cells are mutually shifted by a given value between the converter cells, meets the following equation.

Power converter and method including noise suppression by controlling phase shifting of converter cells

A power converter apparatus having a configuration of a plurality of unit cells, including a DC capacitor and semiconductor devices, connected in cascade, includes a variable voltage source that is connected with a DC link, and a unit having a function that initially charges up the DC capacitor in the unit cell alone selected at a time of an initial charge.

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Hitachi, Japan

Shigenori Inoue