Hitachi, Ltd.

East Japan Railway Company

Yasuhiro Imazu

Motoo Futami

Masaya Ichinose

Akira Bando

Akira Kikuchi

Yasuhiro Kiyofuji

Yoshio Eguchi

Yasuhiro Nakatsuka

Hiromitsu Sakai

Masahiko Honda

Naomi Sato

Shinya Oohara

Jun Narushima

Osamu Sakuchi

Rikiya Inoue

Toshihiko Usui

Masaki Uchita

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.

Control device for railway power conditioner and control system for railway power conditioner

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.

DC/AC power converter with DC side double frequency pulsation suppression caused by AC side faults

An excitation power converter of a doubly-fed generator is protected from excess current to be caused by ground fault or system disturbance and operation continuity of the power converter is ensured. In a power converter system, in order not to flow excess current generated in secondary windings of the doubly-fed generator into the power converter, a rectifier is connected in parallel to the power converter via a reactor, a DC link of the rectifier is connected to a DC link of the power converter, excess current flowing from the secondary windings is separately flowed at a reactor impedance ratio to reduce an amount of current flowing into the power converter, and a semiconductor switching element of an excess current generation arm of the power converter is set to an on-state.

Power converter for doubly-fed power generator system

A wind turbine generator system is equipped with a three phase generator connected to a shaft of a windmill, a converter connected to a stator of the generator, and an inverter connected to the converter and also to an electric power system. The system extracts a torsional vibration component of the shafting between the windmill and generator from the detected rotation speed of the generator, regulates the active component of the current command to the converter according to the vibration component, and controls so as to minimize the rotation speed variation of the generator.

Wind turbine generator system

An object of the present invention is to minimize the torsional vibration caused on the shafting of the wind turbine genarator system so as to operate the windmill stably. A wind turbine genarator system according to the present invention, equipped with a synchronous generator connected to the shaft of a windmill, converter connected to the stator of the synchronous generator, and inverter connected to the converter and also to an electric power system, extracts the torsional vibration component of the shafting between the windmill and synchronous generator from the detected rotation speed of the synchronous generator, regulates the active component of the current command to the converter according to the vibration component, and controls so as to minimize the rotation speed variation of the synchronous generator.

Growing community of inventors

Hitachinaka, Japan

Yasuhiro Imazu