Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Shin-Etsu Chemical Co., Ltd.

Toshiyuki Kikunaga

Akihiko Iwata

Tatsuya Okuda

Takahiro Urakabe

Masaru Kobayashi

Kenichi Koyama

Hirotoshi Maekawa

Akihiro Suzuki

Matahiko Ikeda

Hiroyuki Sasao

Hirotaka Muto

Takeshi Ohi

Kiyoharu Anzai

Osamu Usui

Mitsugu Takahashi

Takumi Kikuchi

Hirofumi Fujioka

Ken Ohashi

Takeshi Horiguchi

Shinichi Kinouchi

Hiroshi Nakatake

Yuuji Kuramoto

Shin-ichi Kinouchi

Mitsugu Takahasi

Takeo Takada

Hiroyuki Asano

Three or more circuits, in which series-connected low-voltage and high-voltage side switches including MOSFETs including parasitic diodes are connected across positive and negative terminals of each of smoothing capacitors, are connected in series. One of elementary series circuits, each including a capacitor and an inductor, is disposed between any adjacent two of the circuits with the elementary series circuits set to have the same period of resonance. The MOSFETs of rectifier circuits are brought into an ON state simultaneously with the MOSFETs of a driving inverter circuit and brought into an OFF state earlier than the MOSFETs of the driving inverter circuit by a period of time not exceeding a time period equal to (period of resonance)/2. A resonance phenomenon of the capacitor and the inductor is used and conduction loss in the rectifier circuits is reduced in DC/DC power conversion performed through charging and discharging operation of the capacitor.

DC/DC power converting apparatus

Three or more circuits including a driving inverter circuit and rectifier circuits are connected in series, each of the circuits including a high-voltage side MOSFET and a low-voltage side MOSFET connected in series as well as a smoothing capacitor having positive and negative terminals between which the MOSFETs are connected. LC series circuits, each including a capacitor and an inductor, are disposed individually between one specific circuit and the other circuits with periods of resonance of the LC series circuits made equal to one another. In performing DC/DC power conversion through charging and discharging operation of the capacitors, a resonance phenomenon of the LC series circuits is used to improve conversion efficiency and achieve a reduction in size of the apparatus structure.

A DC/DC power conversion device includes n-stage circuits comprised of an inverter circuit for driving which is connected between positive terminals and negative terminals of smoothing capacitors, and a rectifier circuit which is connected between positive terminals and negative terminals of smoothing capacitors; a first circuit corresponding to at least one among the n-stage circuits and configured by connecting in parallel cell circuits of m, second circuits corresponding to a plurality of remaining circuits of (n&#x2212;1) among the n-stage circuits; capacitors for energy transfer connected between middle points of the cell circuits and middle points of the second circuits; and column circuits of m comprised of the cell circuits, the second circuits and the capacitors for energy transfer, wherein the middle points are contact points of high voltage sided elements and low voltage sided elements of the cell circuits and the second circuits; and driving signals for driving the respective column circuits have the same driving cycle and are out of phase with each other.

DC/DC power conversion device

Voltage compensating circuits are connected serially to a power system, including capacitors each having different charging voltages (in relationship of approximately 2(K=0, 1, 2, . . . ) times the smallest charging voltage value). The voltage compensating circuits convert DC voltages in the capacitors into AC voltages and output the AC voltages, respectively. The voltages of the capacitors are detected as detected values Vto VThe detected values Vto Vare used as bit signals for a reference value to check a voltage dip amount of the power system with the reference value and to convert the voltage dip amount into a binary signal. A combination is selected from the voltage compensating circuits in accordance with the binary signal so that the sum of output voltages of the selected voltage compensating circuits compensates the voltage dip of the power system.

Voltage fluctuation compensating apparatus

A motor driving apparatus makes a carrier signal of an inverter be synchronized with a carrier signal of a DC/DC converter, and determines a phase difference between both the carrier signals based on a ratio of an input voltage inputted to the DC/DC converter and an input voltage inputted to the inverter, and a percentage of modulation and a power factor which are operation parameters of the inverter. When the frequency of the carrier signal of the DC/DC converter is set to be twice as high as that of the carrier signal of the inverter, an optimal phase difference is determined based on the ratio of the input voltage of the DC/DC converter and the input voltage of the inverter.

Motor driving apparatus

A load is connected to a first battery group. The first battery group and a second battery group are connected in series to each other. A bidirectional DC/DC converter for electric power migration between the first battery group and the second battery group is provided.

Battery power circuit and automobile battery power circuit

Voltage compensation circuits connect DC voltages accumulated in capacitors having respectively different charging voltageswhich are 2(where K=0, 1, 2, . . . ) times the minimum voltage into AC voltages. The voltage compensation circuits are connected in series to an electric power system in series. When the voltage dip occurs in an electric power system, a combination of voltage compensation circuits is selected from the voltage compensation circuits. The sum of the output voltage compensates the voltage dip. During normal operation, a high speed mechanical short circuit switch by-passes the voltage compensation circuits to reduce power loss.

In an IGBT module which contains an IGBT device and a diode device connected to each other and accommodated in a case and which radiates heat generated in operation through a radiation board, an object is to reduce the area of the module in the lateral direction to achieve size reduction. The collector electrode surface of an IGBT device is provided on a radiation board, and an element connecting conductor is bonded with conductive resin on the emitter electrode surface. The anode electrode surface of a diode device is bonded on it with the conductive resin. The IGBT device and the diode device are thus stacked and connected in the vertical direction.

Semiconductor module

Voltage compensating circuits are connected serially to a power system, including capacitors each having different charging voltages (in relationship of approximately 2 (K&equals;0, 1, 2, . . . ) times the smallest charging voltage value). The voltage compensating circuits convert DC voltages in the capacitors into AC voltages and output the AC voltages, respectively. The voltages of the capacitors are detected as detected values V to V . The detected values V to V are used as bit signals for a reference value to check a voltage dip amount of the power system with the reference value and to convert the voltage dip amount into a binary signal. A combination is selected from the voltage compensating circuits in accordance with the binary signal so that the sum of output voltages of the selected voltage compensating circuits compensates the voltage dip of the power system.

In semiconductor equipment, a switching timing adjuster is provided between insulated gate bipolar transistors and a control signal generator. The switching timing adjuster includes an input decision circuit that decides whether a signal output from the overvoltage protector is a signal that has been output due to a deviation in the switching timing at a turn-off or turn-on time, a signal holding circuit that holds a signal that is output from the input decision circuit, and a pulse formation circuit that forms a corrected switching control signal based on a signal held in the signal holding circuit and a switching control signal from the control signal generator.

Semiconductor equipment

A current detecting sensor includes parallel flat plates opposed in a substantially U-shape in cross-section. Since the flat plates are opposed to each other, the current detecting sensor has reduced inductance, significantly decreasing frequency dependency of outputs from detection terminals.

Power semiconductor module

An object is to obtain long-term reliability of an electric connection in a power semiconductor module. In a power semiconductor module, the main circuit interconnection directly connected to a power semiconductor chip (,) is formed of a busbar (,) and the power semiconductor chip (,) and the busbar electrode (,) of the busbar (,) are electrically connected through a conductive resin (,). A member (,) having lower thermal expansion than the busbar electrode (,) is joined to the busbar electrode (,) in the part adjacent to said power semiconductor chip (,).

A gyrotron system comprises an electron gun that produces an electron beam, a magnetic field generating unit comprising a permanent magnet and two electromagnets and capable of generating an axial magnetic field that drives electrons emitted from the electron gun for revolving motion, a cavity resonator that causes cyclotron resonance maser interaction between the revolving electrons and a high-frequency electromagnetic field resonating in a natural mode, a collector for collecting the electron beam traveled through the cavity resonator, and an output window through which a high-frequency wave produced by the cyclotron resonance maser interaction propagates. The gyrotron system can be fabricated at a comparatively low cost, is easy to operate, has a comparatively small size and is capable of operating at a comparatively low running cost.

Gyrotron system having adjustable flux density

The invention provides a cylindrical permanent magnet unit suitable for application to gyrotrons. Essentially the magnet unit consists of two cylindrical permanent magnets which are coaxially aligned, and there is a space between the two cylindrical magnets. Each of the two cylindrical magnet is a coaxially juxtaposed assembly of a plurality of ring-like permanent magnets, and each ring-like magnet is constructed of a plurality of permanent magnet segments. In one of the two cylindrical magnets every ring-like permanent magnet is magnetized in radial directions from the inside toward the outside, and in the other every ring-like permanent magnet is magnetized in radial directions from the outside toward the inside. In the bore of the cylindrical magnet unit the magnetic field is in the direction of the longitudinal center axis of the bore. By virtue of the space between the two cylindrical magnets, the distribution of flux density in the direction of the center axis becomes flat in a middle section of the bore. A ring-like member of a nonmagnetic material may be inserted in the aforementioned space.

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Tokyo, Japan

Toshiyuki Kikunaga