Hitachi, Ltd.

Tetsuya Kato

Shigenori Inoue

Shuji Katoh

Jun Narushima

Takashi Ikimi

Tomomichi Ito

Mitsuyoshi Tsuchiya

Tadashi Sodeyama

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 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

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

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

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.

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Hitachiota, Japan

Tetsuya Kato