Hitachi, Ltd.

Hitachi Construction Machinery Co., Ltd.

Hitachi Mitsubishi Hydro Corporation

Other

Hitachi Industry & Control Solutions, Ltd.

Hitachi Industrial Products, Ltd.

East Japan Railway Company

Hitachi Information & Control Solutions, Ltd.

Yasuhiro Kiyofuji

Akira Bando

Masaya Ichinose

Masakazu Ishikawa

Tomomichi Ito

Kazuhiro Imaie

Keizo Shimada

Naoshi Sugawara

Motoo Futami

Eiji Kobayashi

Shuji Katoh

Takashi Yagyu

Yusuke Seki

Shin Kokura

Satoru Funaki

Toshiki Shimizu

Akihiro Onozuka

Kenta Watanabe

Yasuhiro Imazu

Takahiko Kikui

Kazuo Sato

Hiroyuki Fujita

Manabu Kubota

Yasuhiro Nakatsuka

Wataru Sasaki

Akira Kikuchi

Shigeta Ueda

Hiromitsu Sakai

Masahiko Honda

Naomi Sato

Yusaku Otsuka

Kazuo Suzuki

Shigenori Inoue

Takashi Yabutani

Masashi Suenaga

Katsumi Yoshida

Hironari Kawazoe

Naoya Mashiko

Hideaki Masuko

Chikara Tanaka

Tatsuyuki Ootani

Hideki Ogata

Masashi Toyota

Jun Narushima

Yasuyuki Furuta

Yu Iwasaki

Hikaru Meguro

Osamu Sakuchi

Shoichi Ozawa

Shoichiro Koseki

Akihiro Nakano

Yasuaki Nakayama

Yuta Sugimoto

Atsushi Nishioka

Hisashi Terae

Takenori Kasahara

Makoto Kadowaki

Yukiko Tahara

Yosuke Nakaide

Akira Maekawa

Toshihiko Usui

Minoru Numano

Hidechiyo Tanaka

Rikiya Inoue

Tetsuhiro Fujimoto

Shintarou Oku

Fujiya Kawawa

Masaki Uchita

Syuichi Nagayama

There is provided an adjustable speed generator motor system with full power converter (FPC system) in which two 3-level converters are connected back-to-back on the DC side, and by providing a mode in which a fly-wheeling diode is forced to conduct a current independently for three phases according to the current polarity and a mode in which the fly-wheeling diode is forced to conduct a current independently for three phases according to magnitude relation of the absolute value of a 3-phase AC current and the current polarity of each phase the FPC system is capable of continuing stable operation.

Adjustable speed generator motor system with full power converter

A modular multilevel power converter includes: a capacitor voltage adjuster that calculates an active current component command to make an average voltage of capacitors match a command value; an active power detector that receives an AC current signal and an AC voltage signal and calculates an active power; an active power adjuster that calculates a DC current command value to make the active power match a command value; a first active power command suppressor that suppresses an absolute value of an active power command value; and a second active power command suppressor that adjusts an absolute value of an active power command value.

Modular multilevel power converter and variable speed generator-motor

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 power conversion apparatus including a three-phase transformer having at least four three-phase windings, and three converter arms each configured by connecting one or plural unit converters each including a switching device and an energy storage element in series. A power source or a load is connected to a first three-phase winding of the transformer, three series circuits which connects second and third three-phase windings of the transformer, and the converter arms in series with each other are connected in parallel, the parallel connection point is a DC terminal, and a magnitude relationship between a coupling coefficient of the first and second three-phase windings, and a coupling coefficient of the first three- and third three-phase windings is equal to a magnitude relationship between a coupling coefficient of the fourth and second three-phase windings, and a coupling coefficient of the fourth and the third three-phase windings.

Power conversion apparatus and high-voltage DC transmission system

The present invention provides a duplexed operation processor control system that includes operation processors, an I/O device, and at least one communication path that couples the operation processors to the I/O device, and at least one communication path that couples the operation processors with each other. The duplexed operation processor control system switches over either of the operation processors to be a primary operation processor that executes a control operation for a control target, and the other to be a secondary operation processor that is in a stand-by state, and the secondary operation processor snoops control data synchronously when the primary operation processor acquires the control data from the control target.

Duplexed operation processor control system, and duplexed operation processor control method

The excitation overcurrent detection unit for the doubly-fed electric machine is provided with a function to determine an excitation current magnitude relationship among three phases. The firing pulse is held to on-state or off-state to cause the largest-current phase and the second-largest-current phase to charge the DC capacitor by the operation of diodes. The conduction ratio of the third-largest-current phase or minimum current phase is controlled according to the detected current value to protect against a possible short-circuit across the DC capacitor. When the voltage of the DC capacitor exceeds a preset value, the voltage is suppressed by operating active or passive power devices.

Doubly-fed generator and doubly-fed electric machine

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

A fault diagnosis apparatus and method capable of simultaneously detecting the fault of a multiplexer and the fault of an A/D converter and isolating and identifying causes of these faults, the multiplexer and the A/D converter being used in a multi-channel analog input/output circuit. Test-voltage values are inputted from a diagnosis-voltage input unit into the multiplexer and the A/D converter constituting an analog-signal conversion unit, the multiplexer having plural channels, the A/D converter converting outputs from the multiplexer into digital signals, the test-voltage values being different from each other for each channel of the multiplexer. Comparisons are made between the digital voltage values and the test-voltage values inputted, the digital voltage values being outputted for each channel of the multiplexer. From this comparison result, it is judged whether the multiplexer is at fault or the A/D converter is at fault.

Fault diagnosis apparatus and fault diagnosis method of multi-channel analog input/output circuit

A failure is detected immediately and certainly, and continuation of processing in an unstable state is prevented. A first error detection code is generated from first information which is output as a result of execution of a predetermined program conducted by a first processor. A second error detection code is generated from second information which is output as a result of execution of the program conducted by a second processor which is configured so as to output the same computation result as that of the first processor. It is detected whether the first information is the same as the second information, and it is detected whether the first error detection code is the same as the second error detection code. Writing the first information or the second information into a main memory is controlled on the basis of a result of the detection.

Control apparatus and control method

An electric motor control system including a generator, an AC motor, a power converter for driving the AC motor using a DC output voltage of the generator, and an electric motor controller for controlling the power converter. The electric motor controller controls the power converter by predicting a change in the DC voltage.

Electric motor control system, series hybrid vehicle, electric motor control apparatus, and electric motor control method

In an electric drive system for a vehicle, an alternator is driven by an engine to generate electric power which is used to drive a motor to generate a driving force. During a retardation of the vehicle, the motor is operated as an alternator to convert kinetic energy to electric energy which is used to retard the vehicle. A retard resistor is provided for absorbing electric energy generated during the retardation state. The retard resistor is cooled down by an AC blower.

Electric drive system for vehicle, electric control system for vehicle, electric drive method for vehicle

In a system to which a fluctuating load is connected, compensating for fluctuation in voltage harmonics at the load connecting point and fluctuation in system current harmonics has been difficult for a power converting device connected in parallel with the load. To resolve the problem, a power converting device connected in parallel with a fluctuating load includes: a Fourier series expansion unit which executes Fourier series expansion to load current by use of a reference sine wave in sync with a system and thereby outputs Fourier coefficients; and a fundamental component calculating unit which calculates a positive phase active fundamental component of the load current from the Fourier coefficients. A current instruction of the power converting device is generated by subtracting the fundamental current from the load current. With the current instruction, the fluctuations in system current harmonics and in voltage harmonics at the connecting point can be compensated for.

Power converting device and method for controlling the same

A motor is driven with variable frequency AC power converted from DC power, and an AC output power from the motor is converted to DC. In the conversion, an electromotive force regenerated by the motor is consumed by a plurality of resistors. When the consumption of the electromotive force is impeded in any of systems including any of the plurality of resistors, the electromotive force is consumed by the systems including the remaining resistors. Even if a system including any of the plurality of resistors fails, the electromotive force can by consumed by the other systems including the remaining resistors, thus providing a reliable rheostatic brake.

AC drive apparatus, vehicle control apparatus, and power conversion method and vehicle control method

The operation-state data of the uninterruptible power supply unit for the operation time of the uninterruptible power supply unit (UPS) deployed between the load facility and the commercial power source and used for the uninterruptible operation is provided, the guarantee charge dependent on the time during which the operation of the uninterruptible power supply unit is guaranteed is stored, the stored guarantee charge is displayed as the amount billed when the provided operation-state data satisfies the stored guaranteed time. The provided operation-state data is input into the remote supervisory unit through the communication apparatus as well as an the identical operation-state data is displayed at the data display unit at the uninterruptible power supply unit.

Guarantee charge processing method and apparatus

A power converter system includes: a circuit breaker having one terminal connected to a power system and another terminal connected to a load; a transformer for interconnection; a power converter; and a controller for controlling the power converter, wherein, during a return to grid connected operation, the power converter is controlled such that the phase of an output voltage of the power converter matches the phase of the system voltage, and the circuit breaker is closed, so as to prevent an overcurrent during a changeover from the self commutated operation to the grid connected operation of the power converter.

Phase synchronization system for connecting a power converter to a power distribution system

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Hitachi, Japan

Yasuhiro Kiyofuji