Mitsubishi Electric Corporation

Mitsubishi Denki Kabushiki Kaisha

Nagaoka University of Technology

Mitsubishi Generator Co., Ltd.

Tatsuya Okuda

Takahiro Urakabe

Akihiko Iwata

Masaru Kobayashi

Hirotoshi Maekawa

Matahiko Ikeda

Kikuo Izumi

Toshiyuki Kikunaga

Yoshikazu Tsunoda

Kenji Fujiwara

Takahiro Kato

Tomoyuki Kawakami

Yuuji Kuramoto

Masaru Fuku

Kiyoharu Anzai

Yu Kawai

Takeshi Ohi

Yuuya Tanaka

Hiroshi Ito

Masaya Inoue

Nicolas Voyer

Toru Kimura

Osamu Mori

Takushi Jimichi

Dai Nakajima

Toshiyuki Yoshizawa

Naoki Yoshimatsu

Takayoshi Nagai

Kazutoshi Kaneyuki

Shigeki Harada

Yuya Tanaka

Taichiro Tsuchiya

Takaharu Ishibashi

Takeshi Horiguchi

Takamasa Asai

Osamu Usui

Hirotaka Muto

Takanobu Yoshida

Minoru Aoki

Hiroshi Nakatake

Tomoaki Kimura

Masakazu Fukada

Takeshi Amimoto

Toshinori Yamane

Masahiro Sugahara

Gustavo Buiatti

Jun-ichi Itoh

Naohide Tsuchimoto

Takuya Michinaka

Majumdar Gourab

Shin-ichi Kinouchi

Tsutomu Shimazaki

Hoai Nam Le

Sigetada Gotou

Wataru Yamashita

Shigetada Mitsubishi Denki KK Gotou

A metal support structural body is provided on the radially outer side of a phase ring for connecting a rotating electric machine armature winding at a stator end. An insulator ensuring an insulation distance to the ground is interposed between the phase ring and the metal support structural body. Thus, long-term reliability improves as compared to a conventional insulation-to-ground structure. Since the insulation distance to the ground is ensured by the insulator, the phase ring and the metal support structural body are configured with an insulation thickness smaller than needed for insulation to the ground, thereby improving cooling performance for the phase ring and the metal support structural body. Occurrence of induced current in the metal support structural body is suppressed, thus allowing application of a simple fastening structure such as metal bolts to a stator frame.

Phase ring support structure and rotating electric machine

Stacked core sheets forming a stacked core of a rotating electric machine have tooth portions on the inner circumferential side. Axial-direction holes penetrating the stacked core in the axial direction are provided near the tooth bases and near the outer circumferential surface. Resin is injected through tooth base neighbor holes near the tooth bases and core outer circumferential holes near the outer circumferential surface of the stacked core, among the axial-direction holes in the rotating electric machine. Thus, the resin fills gaps near the tooth bases and near the outer circumferential surface of the stacked core, so that the stacked core sheets are bonded to each other, thus obtaining a rotating electric machine having such a stacked core.

Rotating electric machine and method for manufacturing rotating electric machine

A power conversion device converts a direct-current power on the DC side of the power conversion device to an alternating-current power by an inverter circuit having a plurality of semiconductor switching elements, and outputs the AC power from the AC side of the power conversion device. A current detector detects a reactor current output from the inverter circuit. As overcurrent detector detects overcurrent in a control mode in which the reactor current is caused to follow a reactor current command value, control circuit starts an overcurrent mode in which a time period where the reactor current monotonically decreases is provided. In the overcurrent mode, whether to switch the overcurrent mode to the normal control mode is determined based on the reactor current or in accordance with a timing corresponding to a zero-cross point of a voltage or current on the AC side.

Power conversion device

A control circuit corrects a reference gain by multiplying the reference gain by a correction value set in association with state-of-charge information of a storage battery, and uses the corrected reference gain as a first gain for controlling a DC/AC inverter, to adjust the slope of frequency drooping characteristic. The correction value is a value that gradually decreases with increase in state-of-charge information of the storage battery, the minimum value of the correction value is N1 which is a real number greater than 0 and corresponding to a first state of charge for stopping charging of the storage battery, and the maximum value of the correction value is N2 which is a real number greater than N1 and corresponding to a second state of charge for stopping discharging of the storage battery.

Power conversion device and power conversion system

A power conversion device which reduces switching losses and stabilizes the output power. A switching-mode changer generates a reference signal for switching a mode of operation of the full-bridge circuit to a first switching mode or a second switching mode. In the first switching mode, an upper arm and a lower arm are switched synchronously, and a lower arm and an upper arm are non-conducting. In the second switching mode, the lower arm and the upper arm are switched synchronously, and the upper arm and the lower arm are non-conducting. The switching-mode changer adjusts the phase of the reference signal so that the reactive power is reduced.

A power system and a power conversion device are interconnected via an interconnection switch. A user load is provided between the power conversion device and the interconnection switch. In parallel with the interconnection switch, a series circuit composed of a load disconnection switch and a voltage maintenance load for maintaining voltage of the user load at the time of system momentary power interruption is connected. Control is performed such that, when momentary power interruption occurs, the interconnection switch is turned off and the power system and the power conversion device are connected via the voltage maintenance load, and at the time of recovery from the momentary power interruption, the interconnection switch is turned on, further the power system and the power conversion device are connected.

Power conversion system for power system interconnection

In a control unit for drive-controlling a switching element unit of each power conversion device, a voltage correction amount calculation unit calculates a correction amount corresponding to voltage drop due to impedance between the switching element unit and filter reactor. A voltage command correcting unit corrects a voltage command generated by the voltage command generation unit, using the correction amount. Thus, for a power conversion devicethat has a small output impedance, correction is performed so as to increase the output impedance, and a PLL unit changes the frequency in accordance with active power calculated from output voltage and output current of the power conversion device, so as to uniform power allocations.

Electric power conversion device and electric power conversion system

A power conversion circuit for converting DC power supplied from a DC power supply to AC power; and a power conversion control section for controlling operation of the power conversion circuit so as to generate autonomous operation power as an AC voltage source in a parallel-off state from a power grid. The power conversion control section includes: an AC voltage control section for controlling AC voltage; an AC current suppression section for limiting AC current to a predetermined current limit value or smaller; and a DC voltage shortage suppression section for, when DC voltage of the power conversion circuit reduces, in response thereto, reducing the current limit value to be given to the AC current suppression section.

Power conversion device with an autonomous operation function

Using two converters placed in a primary-side and a secondary-side and each configured as a single-phase full-bridge, and one single-phase transformer TR, a power conversion device converts DC power of a primary-side capacitor to which a primary-side DC voltage is applied, to DC power of a secondary-side capacitor to which a secondary-side DC voltage is applied, through a transformer. A control device sets a dead time Tdfor the converter serving as a power-transferring side converter, to be equal to or less than a current-polarity reversal time Tcmtt, to thereby surely achieve zero-voltage switching.

In a power control system which connects power from the power storage device to a power grid and supplies power to a load, the power from the power storage device is connected to the load and the power grid via a DC/DC converter, a smoothing capacitor, and a DC/AC converter. By a first power control unit for controlling flow power of the power grid to be a power command value, and by a second power control unit for suppressing reverse flow power, an output power command for the DC/AC converter is generated, an output power command for the DC/DC converter is generated so that voltage of the smoothing capacitor becomes target voltage, and the output power command is corrected so as to suppress voltage variation in the smoothing capacitor.

Power control system

In a DC/DC converter, a first operation section calculates a first operation value, based on a difference voltage between an instruction value for a high-voltage-side voltage and a detected value of a high-voltage-side voltage, a second operation section calculates a second operation value, based on a difference voltage between a voltage instruction value for a charge-discharge capacitor and a voltage detected value of the charge-discharge capacitor, and a switching control section obtains a conduction ratio, based on the first operation value and the second operation value, and controls, based on the conduction ratio, switching operations of first to fourth semiconductor circuits, thereby controlling the high-voltage-side voltage, and the voltage of the charge-discharge capacitor.

DC/DC converter

A method and apparatus for controlling the output voltage of a boost converter including a number n of bridge devices connected in series, each bridge device including plural switches and a capacitor. The method and apparatus provide control of the switches according to a selected periodical matrix pattern including a number N of time intervals, N being a positive integer greater than 2, and in that in each time interval, the voltage between the input and the output of each ith bridge device with i from one to n, is equal to one of a null value, a number ki times a positive value, and minus the number ki times the positive value, the positive value being the result of the division of the output voltage of the boost converter including the n bridge devices by the number of time intervals N of the periodical matrix pattern.

Method and an apparatus for controlling the output voltage of a boost converter composed of plural bridge devices

An object of the present invention is to provide a DC/DC power conversion apparatus that can reduce the average power consumption over a wide range of DC voltage ratios. A control circuit () changes a switching frequency f at which IGBTs Sto Sperform ON/OFF operation, in accordance with a voltage ratio k (k=V/V) for DC voltage conversion, based on the following expressions, such that a magnitude &#x394;I of a current ripple flowing in a reactor Lc is a predetermined constant value irrespective of the voltage ratio k.

DC/DC power conversion apparatus

In a power conversion device which performs DC/DC conversion, an inverter circuit (), which is formed of one or more single-phase inverters () and () connected in series to each other, is connected in series to a DC power supply () in its subsequent stage. In further subsequent stage, a smoothing capacitor () connected to the inverter circuit () via a rectifier diode (), and a shorting switch () which bypasses the smoothing capacitor () are provided. The shorting switch () is switched ON to charge capacitors () and () included in the single-phase inverter () and (), respectively, whereas the shorting switch () is switched OFF to discharge the capacitors () and (), whereby the voltage of the smoothing capacitor () is controlled.

Power generated by a solar battery of thin-film type is stepped up to a predetermined DC voltage by a step-up chopper circuit, and the predetermined DC voltage is converted into three-phase AC power by an inverter circuit, and the three-phase AC power is supplied to an AC power supply system via an output DC voltage circuit. The solar battery is not grounded, and a negative electrode thereof has a floating capacitance between the negative electrode and the ground. The AC power supply system is configured by three-phase star-connection, and the neutral point is grounded. The output DC voltage circuit includes three batteries, and the batteries are provided, for the respective phases, between the AC power supply system and a sine wave filter connected to the AC output side of the inverter circuit. Therefore, it is possible to prevent acceleration of the deterioration of the solar battery.

Power conditioner for photovoltaic power generation

Growing community of inventors

Tokyo, Japan

Tatsuya Okuda