Kabushiki Kaisha Toshiba

Tokyo Shibaura Denki Kabushiki Kaisha

The Tokyo Electric Power Company, Incorporated

Tokyo Electron Power Company Incorporated

Haruhisa Inokuchi

Takami Sakai

Syunichi Hirose

Noriko Kawakami

Hirokazu Suzuki

Fumitoshi Ichikawa

Naomi Nakamura

Kenichi Suzuki

Yukio Tokiwa

Koji Sakamoto

Ken-Ichi Suzuki

Accident detection circuit of a voltage-type self-excited power converter

A control system for a power conversion system composed of a plurality of power converters, each of which is connected between one of a plurality of AC power systems and a DC line to exchange an electric power between them, respectively. The control system is composed of a plurality of control units, each of which includes units for detecting an AC current flowing between the AC power system and the power converter, an AC voltage of the AC power system, and a DC voltage of the power converter, and a unit for detecting an active power and a reactive power exchanged between the power converter and the AC power system. Each of the control units further includes an active power control unit for generating an active current command so that the DC voltage drops with the increase of one of the active power and a DC current, a unit for setting a reactive power reference, a reactive power control unit for comparing the reactive power reference and the reactive power to obtain a reactive power difference and for generating a reactive current command so as to bring the reactive power difference close to zero, a current control unit for generating a plurality of output voltage commands so as to coincide the AC current to the active and reactive current commands, and a gate control unit for switching the semiconductor switching devices in the power converter based on the output voltage commands.

Control system for power conversion system

An inverter control device that controls a self-commulated inverter connected to an AC power system via a three phase transformer and in so doing suppresses DC magnetization in the three-phase transformer. The device includes a current DC component detecting circuit for detecting the current DC components contained in at least two of the three phase output AC currents of the inverter and a DC magnetization suppressor signal generating circuit for producing two correcting signals from the current DC components. The two correcting signals are used to balance in amount the three voltage DC components contained in the three phase output AC voltage of the inverter, respectively. An output reference correcting circuit is provided to correct two of first output references in accordance with the two correcting signals and output three second references including the two corrected values and one of the first output reference. A gate control circuit controls the three phase output AC voltages of the inverter according to the three second output references.

Inverter control device capable of supressing DC magnetization in

A coupling system in which power converters are coupled through a DC circuit to exchange active power between the converters comprises a control apparatus for controlling active power exchanged between each converter and its AC system. The control apparatus includes an automatic active power regulator for regulating active power exchanged between the converters and the AC system to be equal to be predetermined active power reference value, and an automatic DC voltage regulator for regulating a DC voltage of the DC circuit to be equal to a predetermined DC voltage reference value. When an output signal from the automatic active power requlator of each converter is input as an upper limit value of an output signal from the automatic DC voltage regulator, a DC voltage reference value of one converter is set to be equal to or larger than a DC voltage reference value of the remaining power converter.

Control apparatus of DC power coupling system

In a DC power transmission system wherein two AC systems are interconnected by a first converter, a DC transmission line and a second converter to transmit power from one of the AC systems to the other of the AC systems via the DC transmission line, the DC power transmission system is provided wherein at least one of the first and second converters operating as an inverter is a current type self-commutated converter capable of being pulse-width controlled, the reactive power of the current type self-commutated converter is regulated by controlling a phase difference angle between its AC voltage and current, the DC voltage is regulated by pulse-width controlling the current type self-commutated converter, and the DC current is regulated by the converter operating as a rectifier.

DC power transmission system

A power converter device that interchanges power between a first A. C. system and a second A. C. system, including an externally commutated power converter controlled such that the D. C. voltage of a D. C. line tracks a reference value, a voltage type self-commutated power converter which converts the output D. C. power of the externally commutated power converter to A. C. power under pulse width control and supplies the converted A. C. power to the second A. C. system, interchange power control means for controlling the phase difference angle of the voltage on the A. C. side of the voltage type self-commutated power converter and the voltage of the second A. C. system such that the interchange power tracks a reference value, and reactive power control means for controlling the control factor of the pulse width control such that the reactive power generated by the voltage type self-commutated power converter tracks another reference value.

Power converter

A power converter control apparatus includes an automatic power controller for controlling a rectifier and an automatic reactive power controller for controlling an inverter. The inverter is coupled via DC power transmission lines to the rectifier. An output from the automatic power controller is utilized to change a control angle (or margin angle) of the inverter if a DC current flowing through the DC power transmission lines increases to exceed a rated current value of the apparatus, thereby allowing a stable power transmission.

Power converter control apparatus and power converter control method

A converter control system for DC power transmission line performs the following operation. When the DC current flowing through an inverter decreases to a value being smaller than a rated current value by a value in excess of a predetermined value, a reference voltage value determining the DC voltage of the inverter decreases. The decrease of this reference voltage value is limited to a given extent, so that a partial constant current characteristic portion appears at the voltage decreased portion in the DC voltage/current characteristic of the inverter. Then, an automatic voltage regulator of the inverter is rendered always active.

Converter control system having stable power transfer in the presence of

In a method and a system for terminating inverter operation of a converting device connected to a DC power transmission system and having a bridge connection of thyristor valves, absence of a current flowing through the converting device is detected to provide an absence detection signal indicative of such absence, and the absence detection signal is used as one condition for effecting termination of the inverter operation. According to the invention, the absence is found when all the valves in at least one of the lower potential side and the higher potential side are found concurrently non-conducting, and each valve is found non-conducting when a voltage is found present across each valve.

Method and system for terminating operation of an HVDC invertor

A control device for a converter used in a DC transmission system comprises an automatic current regulator, an automatic margin-angle regulator and an automatic voltage regulator. The output of the automatic voltage regulator is supplied to the automatic margin-angle regulator to vary a margin-angle reference of the automatic margin-angle regulator.

Growing community of inventors

Kunitachi, Japan

Haruhisa Inokuchi