The Tokyo Electric Power Company, Incorporated

Kabushiki Kaisha Toshiba

Meidensha Corporation

Kenichi Suzuki

Noriko Kawakami

Haruhisa Inokuchi

Hirokazu Suzuki

Shoichi Irokawa

Junichi Shimomura

Satoru Ohishi

[Task] In a power conversion system, a variation in PCS alternating current voltage is suppressed during a change operation to a self-contained run according to an instantaneous voltage drop-service interruption. [Means for solving the task] During an ordinary system voltage stabilization, with change switchchanged to the output side of APR control circuitand change switchchanged to the output side of charge/discharge run PWM command value preparing section, the power conversion system is run in a charge/discharge run mode. If the instantaneous voltage drop or the service interruption occurs, change switchis changed to the output side of the self-contained run change prior current command value preparing sectionand the constant current discharge run is carried out in which the electric power is discharged for a predetermined time duration in response to the current command value of the self-contained run change prior current command value preparing section. Thus, after a predetermined time has elapsed, change switchis changed to the output side of the self-contained run PWM command value preparing sectionto perform the self-contained run. At this time, the variation in PCS alternating current voltage in the power conversion system is suppressed.

Control device for uninterruptible power supply

A power conversion system including a plurality of converter transformers. AC side windings of the converter transformers are connected in series for connecting to an AC power system. The power conversion system further includes a plurality of series connected voltage source type self-commutated converters for converting AC power into DC power or DC power into AC power. Each of the voltage source type self-commutated converters is connected to one of DC side windings of the converter transformers, respectively. The power conversion system further includes a plurality of DC voltage sources. Each of DC output sides of the voltage source type self-commutated converters is connected to one of the DC voltage sources, respectively. The power conversion system further includes a control system for controlling the voltage source type self-commutated converters such that each of DC voltages of the voltage source type self-commutated converters follows to one of DC voltage reference values for the voltage source type self-commutated converters, respectively.

Power conversion system with series connected self-commutated converters

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

Growing community of inventors

Sagamihara, Japan

Kenichi Suzuki