Hitachi, Ltd.

The Kansai Electric Power Co., Inc.

Renesas Technology Corp.

The Kansai Elect. Power Co.

Kenichi Ono

Akira Bando

Hiroto Nakagawa

Eiji Haraguchi

Hiroshi Sugisaka

Hiroshi Kashiwazaki

Naoki Takada

Junichi Maruyama

Hiroyuki Nitta

Yoshihisa Ooishi

Takao Kuwabara

Masahiro Ueno

Toshitaka Yamamoto

Junichi Shiozaki

Ichiro Hitomi

Shigeaki Hayashi

Haruo Nohara

Akihiro Sakayori

Yoji Tanaka

Takao Kuwahara

Masahiro Minato

A display control circuit divides M display data for M pixels assigned to each of plural display driving circuits among display data received in an order of an arrangement of pixels in a row, into plural display data sets each composed of N display data, rearranges the plural display data sets such that one of the plural display data sets assigned to one of the plural display driving circuits is followed by one of the plural display data sets assigned to another of the plural display driving circuits succeeding the one of the plural display driving circuits, and outputs the rearranged display data sets to the plural display driving circuits.

Display control circuit and display driving circuit

In a microcomputer with a programmable ROM, there is provided an external pin at which a mode select signal is entered so as to select one of three modes, including a MCU mode in which an application system is controlled by an application program which has been stored in the programmable ROM, a PROM mode in which the application program is written into the programmable ROM, and an inline mode in which predetermined data is written to a part of the programmable ROM with the microcomputer mounted on a user system.

Microcomputer with programmable ROM

An induction generator/motor system has an induction machine connected at its secondary side to a cyclo-converter. An induced voltage develops when the cyclo-converter pauses during a transient phenomenon occurring in the system. When the induced voltage exceeds a predetermined voltage range which covers the maximum output voltage derivable from the cyclo-converter, the polarity of thyristor converters of the cyclo-converter is switched such that the induced voltage is applied to a thyristor converter to be rendered conductive next in forward relationship therewith, thereby preventing occurrence of an overvoltage.

Induction generator/motor system

In a pumping-up generator/motor system comprising an induction generator/motor, at least one cyclo-converter connected to the secondary winding of the induction generator motor for controlling the rotational speed of the generator/motor in the motor mode and for maintaining the output frequency thereof in the generator mode at a constant level, the center of the speed range of the generator/motor in the generator mode is set near the synchronous speed thereof and a plurality of converter units constituting each cyclo-converter are connected in parallel in the generator mode, and in series in the motor mode thereby allowing the capacity of the cyclo-converter to be made smaller.

Pumping-up generator/motor system and method of operation of the same

Disclosed in a variable speed pumping-up electrical power system comprising a variable speed generator/motor, a frequency converter connected between the generator/motor and an a.c. power system, a controller controlling an effective power input to the generator/motor by controlling the frequency converter on the basis of the difference between an actual effective power input from the a.c. power system and an externally-applied effective power command, and a correction circuit correcting the effective power command on the basis of the difference between the frequency of the a.c. power system and a frequency setting.

Variable speed pumping-up electrical power system

A control system for variable speed hydraulic turbine generator apparatus comprises an induction generator connected at its primary side to an AC power line system, a secondary excitation controller connected to the secondary side of the induction generator and being responsive to a generator output command signal supplied externally to supply to the induction generator an excitation current which causes the induction generator to generate AC power at the same frequency as that on the AC power line system, a hydraulic turbine for rotating the induction generator, a guide valve for regulating the amount of water supplied to the hydraulic turbine, a rotation speed detector for detecting a rotation speed of the induction generator, a rotation speed command calculator for receiving a hydraulic turbine running condition signal inclusive of the external generator output command signal and calculating an optimum rotation speed command, a rotation speed controller for comparing the optimum rotation speed command with a rotation speed signal from the rotation speed detector and producing a guide valve opening control signal in accordance with a difference between the optimum rotation speed command and the rotation speed signal, and a guide valve driver responsive to the guide valve opening control signal to deliver to the guide valve a signal which controls the opening of the guide valve in accordance with the guide valve opening control signal.

Control system for variable speed hydraulic turbine generator apparatus

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Hitachi, Japan

Kenichi Ono