Hitachi, Ltd.

Tadashi Sodeyama

Motoo Futami

Masaya Ichinose

Shinya Oohara

Kazuhiro Imaie

Shigenori Inoue

Mitsuyoshi Tsuchiya

Tetsuya Kato

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 wind power generation system wherein procedure for controlling the blade pitch is changed in accordance with the rate of decrease in the amplitude of the grid voltage, and when over current occurs in the grid-side power converter, the grid-side power converter is brought into the gate-blocked condition whereas the generator-side power converter continues its operation.

Wind power generation system and operation method thereof

A variable speed wind power generation system including a wind turbine, a generation power command unit for generating a generation power command value based on a state quantity of the wind turbine and a generator control unit for controlling the power converter for controlling electric power of the generator, wherein the generator control unit operates to regulate the generation power of the generator in order to change the generation power amount according to the generation power command value.

Variable speed wind power generation system

Wind power generation system and operating method thereof

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Hitachi, Japan

Tadashi Sodeyama