Toshiba Mitsubishi-electric Industrial Systems Corporation

Oki Electric Industry Co., Ltd.

Yosuke Fujii

Shinzo Tamai

Yasuhiko Hosokawa

Akinobu Ando

Nobuhiro Takahashi

Eiichi Ikawa

Tatsuaki Amboh

Ruben Alexis Inzunza Figueroa

Takeshi Sumiya

A timing specifying device includes count processing circuitry to count an input reference clock; and timing control circuitry configured to set a parameter having an integer part and a fractional part in the count processing circuitry. The count processing circuitry counts the reference clock, outputs a timing signal indicating that a time corresponding to an integer value has passed, and counts a value corresponding to the fractional part at a timing at which the timing signal is output. The integer value is a value indicated by the integer part. The count processing circuitry stops counting of the reference clock when a value obtained by counting the value corresponding to the fractional part carries over from a fraction.

Timing specifying device, image forming apparatus, motor drive device, and timing-signal output method

In a multilevel power converter (), a power conversion circuit is formed of semiconductor modules (to), the multilevel power converter () includes: a capacitor () on the positive electrode side; a capacitor () on the negative electrode side; an AC bus (L); a capacitor bus (L); a positive electrode bus (L); and a negative electrode bus (L), and the semiconductor modules (to) are arranged such that the inductance in a communication loop is reduced.

Multilevel power converter

An operation control apparatus includes a criterion calculator that obtains an operation criterion for the power converter, based on the voltage detected by the above voltage detector on the side of the alternating-current power system, a direct-current voltage detector that detects a direct-current output voltage of the solar battery, and an operation determination device that compares the direct-current output voltage detected by the direct-current voltage detector with the operation criterion obtained by the criterion calculator, and supplies the power converter with an operation command if the direct-current output voltage is greater than the operation criterion.

Operation control apparatus for solar power system

A power conversion apparatus includes an electrical circuit including a heat source, a heat pipe cooler in which a refrigerant is enclosed, the heat pipe cooler configured to cool the heat source, a freeze determiner configured to determine whether the refrigerant is frozen, and an output limiter configured to limit output when the freeze determiner determines that the refrigerant is frozen.

Power conversion apparatus

A power converter apparatus is provided with a lead-in board in which alternating-current power received from power converting units is connected in parallel, and a connection base including frames for installing the power converting units therein. The frames are provided with connection sections for connecting the main circuits of the power converting units. The lead-in board is provided with breakers for cut off alternating-current power from the power converting units.

Connection apparatus for power converter

A power conversion apparatus includes a comparison circuit which compares a determination element related to a loss in the power converter with a switching reference value and outputs a determination instruction when a difference has occurred between them, a determination circuit which outputs a two-level operation switching instruction when the determination element is greater than or equal to the switching reference value, and a switching circuit which, when having received a two-level operation switching instruction, turns off the alternating-current switch and turns on the valve devices in the arm sequentially, thereby bringing the power converter into a two-level operation state.

A synchronous-machine starting device includes an induction voltage operating unit calculating an induction voltage induced to an armature of a synchronous machine based on an estimated phase representing a position of a rotor, an estimated rotational speed of a rotor, an AC voltage signal, and an AC current signal, and outputting an induction voltage signal representing the calculated induction voltage, a selection unit selecting and outputting one of the induction voltage signal received from the induction voltage operating unit and the AC voltage signal received from the AC voltage detection unit, and a feedback operating unit outputting a speed signal representing the calculated estimated rotational speed based on calculated phase error to the induction voltage operating unit, and outputting a position signal representing the calculated estimated phase to the electric power conversion control unit and the induction voltage operating unit.

Synchronous-machine starting device

A synchronous machine starting device in which AC power is supplied to an armature of a synchronous machine, the supplied AC voltage is detected to determine a rotor position of the synchronous machine, and the supplied power is controlled based on the detected rotor position. To detect rotor position, a first position signal indicating a timing at which a level of AC voltage supplied to the armature of the synchronous machine reaches a prescribed value is output. An error of an estimated phase is calculated based on the estimated phase indicating the rotor position and the detected AC voltage, and the estimated phase is calculated based on the calculated error to produce a second position signal indicating the calculated estimated phase. A selected of first and second position signals is output to indicate the rotor position of the synchronous machine for control of AC power supplied to the armature.

Synchronous machine starting device

In a synchronous machine starting device, an AC voltage detection unit detects AC voltage supplied to an armature of a synchronous machine through an electric power line from a power conversion unit. The AC voltage detection unit has a first output end and a second output end isolated from the electric power line, transforms AC voltage supplied through the electric power line at a first ratio to output the transformed voltage from the first output end, and transforms AC voltage supplied through the electric power line at a second ratio and then limits the transformed voltage to a prescribed positive voltage value or lower and a prescribed negative voltage value or higher for output from the second output end. Then, a detected voltage selection unit selects one of the voltage received from the first output end and the voltage received from the second output end, and outputs the selected one to a rotor position detection unit. The rotor position detection unit detects a rotor position of the synchronous machine based on the voltage received from the detected voltage selection unit. A power conversion control unit controls the power conversion unit based on the detected rotor position.

Growing community of inventors

Tokyo, Japan

Yosuke Fujii