Fujitsu Corporation

Kabushiki Kaisha Toshiba

Hiroshi Uno

Tetsu Shijo

Kiichiro Kasai

Yasuhiro Kanekiyo

Qiang Lin

Nobuyoshi Yamasaki

Tomohisa Oyama

Hiroyuki Tanaka

Masatoshi Suzuki

Takao Hakamatani

Nobuyuki Mitsunaga

Toshiharu Nishioka

A bypass circuit of an embodiment includes a switch that shorts-circuit between a first power conversion apparatus and a power storage apparatus. The switch is connected in parallel to a second power conversion apparatus. The first power conversion apparatus converts power generated from natural energy and outputs the converted power to a power distribution grid. The second power conversion apparatus converts surplus power that has not been converted by the first power conversion apparatus and charges the power storage apparatus with the converted power; or converts power discharged from the power storage apparatus and supplies the converted power to the first power conversion apparatus.

Bypass circuit, power system control method, and non-transitory computer readable medium

A control apparatus controlling a power output apparatus that generates, based on input power from one of an electrical grid and a power storage, output power to another of the electrical grid and the power storage is provided. The control apparatus includes: a communicator to receive a grid frequency of the electrical grid and a state of charge of the power storage, or information allowing the grid frequency and the state of charge to be calculated; and a processor to determine an output destination and an output rate of the output power, based on a function of calculating the output destination and the output rate according to the grid frequency. The output destination and the output rate are adjusted according to the state of charge, by the processor changing, according to the state of charge, the function used to determine the output destination and the output rate.

Control apparatus, power system, and control method

According to one embodiment, an electronic apparatus connectable to a partial power system which is a part of a power system and comprises a first power source apparatus, power supply of the first power source apparatus stopped in response to detecting an islanding of the partial power system, includes: controlling circuitry configured to output to the partial power system a first signal to disable detecting the islanding of the partial power system by the first power source apparatus during at least part of a period during which the partial power system is electrically separated from the power system.

Electronic apparatus with detection of an islanding condition

According to one embodiment, a voltage control inverter interconnectable with an electric power system, includes: a voltage detecting circuit configured to detect a first voltage that is a voltage of the electric power system; and a voltage output circuit configured to output a second voltage to the electric power system at a timing depending on a value of the first voltage, the second voltage having a value depending on the value of the first voltage.

Voltage control inverter, power source apparatus, and control method

According to one embodiment, a voltage control inverter interconnectable with a power system, includes receiving circuitry configured to receive a first control command for outputting a voltage to the power system; and controlling circuitry configured to execute the first control command to output the voltage to the power system. The controlling circuitry is configured to skip to execute the first control command in response to the first control command being received during a period in which the power system is in a first state that is different from a normal state.

Voltage control inverter, power source apparatus, energy control system, and voltage control method

According to one embodiment, an electronic circuitry that converts DC voltage into AC voltage includes first to fourth switching circuitries. A cycle includes first and second periods. During the first period, the first and second switching circuitries are turned on, and the third and fourth switching circuitries are turned off, and during the second period, the first switching and second circuitries are turned off, and the third and fourth switching circuitries are turned on. At least one of the first to fourth switching circuitries includes a first switching element and a second switching element in parallel. During a time period during which at least one of the first to fourth switching circuitries is turned on, the first switching element is turned on during a first subperiod, and the second switching element is turned on during a second subperiod that overlaps the first subperiod.

Electronic circuitry for converting DC voltage to AC voltage

A partial response is utilized to record information on a medium and then regenerate the information from the medium. A regenerating system undergoes equalization including subjecting a regeneration signal from the medium to the convolution of(k&#x2212;s&#xb7;D) Such convolution is performed in the regenerating system so that low-frequency band noises are reduced with an improved error rate. The information is decoded from the equalized signal by use of maximum-likelihood detection.

Signal processing method, signal processing circuit and information recording/regenerating apparatus

A partial response is utilized to record information on a medium and then regenerate the information from the medium. A regenerating system undergoes equalization including subjecting a regeneration signal from the medium to the convolution of(k&#x2212;s&#xb7;D)

An extra-HDA record reproducing circuit for outputting write data comprising parallel data is provided outside a disk assembly, and a intra-HDA record reproducing circuit comprising a parallel-to-serial conversion circuit for receiving write data comprising parallel data and converting the write data to serial data, a write amplifier for switching a polarity of a recording current to be supplied to a head according to the write data converted to serial data, and a preamplifier for amplifying a read signal detected by the head is provided within the disk assembly, and the write data is transferred at a high speed at least from the extra-HDA record reproducing circuit to the intra-HDA record reproducing circuit.

Storage device having internal and external recording circuits

A positioning method and a positioning device are disclosed for controlling an actuator and moving it to a target position. The positioning method generates a random wave signal RN and detects a position error from the target position. The servo control signal CV is generated to position the actuator back to the target position, and the random wave signal RN is added to the servo control signal CV to generate a control signal. Since a random, minute vibration is constantly applied to the actuator to avoid the assumption of a static state by bearings of the actuator, the actuator is affected only by dynamic friction, and relative to the control value, its movement is representative of a linear characteristic. As a result, the positioning accuracy is enhanced, and since the random wave is employed, there is no deterioration of the positioning accuracy of the servo system.

Positioning method, positioning device and disk device

An information storage apparatus for carrying out a signal processing for a partial response system through a recording medium. A recording unit converts an RZ input code into an NRZI code and records the NRZI code in the recording medium through a write head, thereby giving a (1&minus;D) waveform processing to the RZ input code. An equalizing unit carries out Nyquist equalization for a reproduction code reproduced from the recording medium through a read head based on an equalizing transmission characteristic obtained by dividing a cosine roll-off characteristic setting &frac14; of a maximum frequency determined by the RZ input code to be a Nyquist frequency by a transmission characteristic of a magnetic recording and reproducing system. A maximum likelihood detecting section carries out maximum likelihood detection for the code string which is Nyquist equalized by the equalizing section.

Narrow band partial response signal processing apparatus, signal processing method and information storage apparatus

A signal processing apparatus in which a signal is processed using a partial response method is provided. The apparatus includes a signal processing unit which performs an operation (1&minus;D) on each bit of an input code, where D indicates a delay of one bit; an equalizing unit which equalizes a bit sequence processed by the signal processing unit to a Nyquist characteristic; and a maximum likelihood detection unit which detects a maximum likelihood bit sequence from the bit sequence equalized by the equalizing unit. The input code of the signal processing unit is a 1/7-conversion RLL code of input data.

Signal processing apparatus utilizing a partial response method, and signal processing method, information recording apparatus, and information reproduction apparatus therefore

Signals are recorded on and reproduced from a magnetic disk by a head with an azimuth angle which changes depending on a radial position on the magnetic disk. The magnetic disk includes a first recording region having tracks recorded with an azimuth angle less than or equal to a predetermined value, a second recording region having tracks recorded with an azimuth angle greater than the predetermined value, and an overlapping region in which two mutually adjacent tracks overlap in a radial direction of the magnetic disk, where a track pitch of the tracks within the first recording region is different from a track pitch of the tracks within the second recording region.

Magnetic disk, magnetic recording and reproducing method and magnetic disk unit

A disk control section of a disk apparatus comprises an identification section for identifying information regarding a position at which the head positioning servo information is stored, a position calculation unit for calculating the position on a disk medium where recording/reproduction of the record information is to be performed, a comparison and decision unit for comparing the information regarding the position identified by the identification unit with the position information calculated by the position calculation unit each time a predetermined command is received from the higher-level device, and for deciding whether or not the position identified by the identification unit is the position at which the record information is to be recorded on or reproduced, and a skip recording/reproduction unit for carrying out control such that when it is judged, on the basis of the result of the comparison made by the comparison and decision unit, that the position identified by the identification unit is the position at which recording/reproduction of the record information is to be performed, the record information is recorded/reproduced while skipping the position identified by the identification unit. Accordingly, it becomes possible to record and reproduce variable-length data even in a sector-servo type disk apparatus and a hybrid type disk apparatus, so that their storage capacities can be used effectively. In addition, recording and reproduction of data can be performed at high speed.

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Kawasaki, Japan

Hiroshi Uno