Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Nifco Inc.

Kenji Yasui

Haruo Suenaga

Makoto Mihara

Shinichi Sakai

Tomotaka Nobue

Hideaki Moriya

Nobuo Shirokawa

Yoshiharu Oomori

Manabu Kinoshita

Yoshiaki Ishio

Kazuho Sakamoto

Hideki Omori

Takeshi Kitaizumi

Keiichi Satou

Hisashi Morikawa

Koji Yoshino

Daisuke Bessyo

Yoshiharu Omori

Masafumi Sadahira

Masayuki Kubo

Emiko Ishizaki

Hisahi Morikawa

Yoshitaka Oda

Hiokaki Moriya

Hidetomo Nagata

Daisuke Bessho

Sakai Shinichi

A directional coupler according to the invention includes an opening in a wall surface of a waveguide, and a coupling line on an outer side of the waveguide. The opening is configured to not cross a tube axis of the waveguide in plan view, and to emit a circularly polarized wave. The coupling line includes first and second transmission lines and output parts disposed at both ends, the first and second transmission lines extending across the opening to cross the tube axis in plan view and being opposed to each other across the center of the opening. The first and second transmission lines are interconnected at a position displaced from an area vertically above the opening.

Directional coupler and microwave heater provided with the same

A microwave heating device according to the present invention includes a microwave oscillation portion including a reference-signal oscillator formed from a quarts oscillator, phase variable portions and phase-locked loops and, further, includes a control portion for controlling the microwave oscillation portion, and plural radiation portions placed on a wall surface of a heating chamber for housing a to-be-heated object, wherein microwaves supplied to plural microwave feeding points provided in the radiation portions are controlled in phase and electric power, thereby controlling the aspect of radiations of microwaves radiated from the radiation portions.

Microwave heating device

In order to provide a microwave heating device and a microwave heating control method which are capable of uniformly heating a to-be-heated object in a desired state, by employing plural feeding portions provided in a heating chamber on the basis of information about reflected electric power from the respective feeding portions; a control portion controls to supply microwave electric power from plural feeding portions to a heating chamber by operating a microwave generating portion at a heating frequency for heating a to-be-heated object, estimates a heating state for the to-be-heated object on the basis of per-unit-time increase/decrease change states of detected levels of detection signals detected by electric-power detection portions, and controls the heating frequency and the microwave electric power supplied from the feeding portions to the heating chamber.

Microwave heating device and microwave heating control method

A microwave heating apparatus includes, within a heating room, a placement table having a horizontal placement surface for placing an object to be heated, and a plurality of feeding portions which are placed on a wall surface of the heating room for supplying microwave electric power to the heating room. The microwave heating apparatus is adapted to relatively move the position of the straight line connecting two feeding portions to each other, with respect to the object to be heated, through a movement mechanism portion, and to detect a phase difference between the microwave electric powers which minimizes reflected electric power returning from the heating room to the two feeding portions, for detecting the state of placement of the object to be heated on the placement table.

Microwave heating apparatus

In a microwave heating apparatus of the invention, microwaves from oscillation partsare divided into a plurality of microwaves by power division partsand inputted to amplification parts, and desired microwave powers from the amplification parts are supplied from feeding partsto a heating chamber. Reflected powers reflected from the heating chamber to the amplification parts via the feeding parts are detected by power detection parts. Each of the feeding parts has a plurality of antennas for supplying the microwaves having different characteristics to the heating chamber, and a control partextracts an oscillating frequency with which the reflected powers detected by the power detection parts are minimum, and causes the oscillation parts to oscillate at the extracted oscillating frequency so as to supply the microwaves having the different characteristics from the plurality of antennas to the heating chamber.

A microwave heating apparatus includes a microwave generation partusing a semiconductor element, and first and second heating chambersto each of which a microwave generated in the microwave generation part is fed. A reflected microwave returned from at least one of the first and second heating chambersto the microwave generation part is transmitted to the other heating chamber by a circulation type non-reciprocal circuit, so that generated power of the microwave generation part is substantially completely consumed upon heating of an article to be heated.

A power control unit for high-frequency dielectric heating is provided. The power control unit controls an inverter circuit for rectifying voltage of an AC power supply, and modulates the on time of a switching transistor during high frequency switching. The power control unit includes an input current detection section for detecting input current from the AC power supply to the inverter circuit and outputting input current waveform information. A conversion section is provided for converting the input current waveform information into a drive signal of the switching transistor of the inverter circuit so that an instantaneous fluctuation of the input current waveform information is suppressed.

Power control apparatus for high-frequency dielectric heating and power control method for the same

An inverter controller controls an inverter. The inverter converts direct current into alternating current of a predetermined frequency. The inverter includes a resonance circuit for fluctuating output of a predetermined object to be controlled. The inverter controller comprises an output fluctuating unit which fluctuates output of the inverter in response to an output value of a temperature detection section which detects a temperature of a switching element of the inverter. The inverter controller further comprises an output increase suppressing unit which suppresses an increase in the output of the inverter for a predetermined time after decrease control in the output of the inverter performed by the output fluctuating unit.

Inverter controller and high-frequency dielectric heating apparatus

A power control unit for high-frequency dielectric heating is provided, and includes an input current detection section for detecting input current from the AC power supply to the inverter circuit and outputting input current waveform information. A conversion section converts the input current waveform information into a drive signal of the switching transistor of the inverter circuit so that instantaneous fluctuation of the input current waveform information is suppressed. A mix circuit mixes the input current waveform information and power control information for controlling so that current or voltage at an arbitrary point of the inverter circuit becomes a predetermined value and generates an on voltage signal. The conversion section converts the on voltage signal into the drive signal so that the on time is shortened in the portion where the input current is large and that the on time is prolonged in the portion where the input current is small.

A power control method for high-frequency dielectric heating is provided. The method includes detecting input current and input voltage from an AC power supply. Input current waveform information and input voltage waveform information are acquired. It is determined whether the magnetron is being oscillated. If so, the input voltage waveform information is added to the input current waveform information until oscillation of the magnetron is detected, and the addition result is converted into the drive signal of a switching transistor of an inverter circuit. If not, the input current waveform, without addition of the input voltage waveform, is converted into the drive signal of the switching transistor of the inverter circuit.

A power control unit for high-frequency dielectric heating is provided. The power control includes an input current detection section for detecting input current from an AC power supply to an inverter circuit and outputting input current waveform information. A conversion section converts the input current waveform information into a drive signal of the switching transistor of the inverter circuit so that instantaneous fluctuation of the input current waveform information is suppressed. An input voltage detection section detects input voltage from the AC power supply to the inverter circuit and outputs input voltage waveform information. A selection section selects the input current waveform information or the input voltage waveform information, whichever is larger. The conversion section also converts the selected input current waveform information or input voltage waveform information into the drive signal of the switching transistor of the inverter circuit.

A booster transformerfor driving a magnetron includes a bobbinon which at least a first windingand a secondary windingare wound and a coreinserted through the center of the bobbin, wherein a winding area of the secondary windingis divided into two areas while interposing a partition wall, and an outer diameter d of a wire material of the secondary windingand a width tof each of the divided winding areas are so set as to satisfy the relation t

Booster transformer for driving magnetron and transformer unit having the booster transformer

In a step-up transformer for magnetron driving in which two ferrite cores are opposed to each other with a gap G interposed therebetween, thereby forming a magnetic circuit including a middle core section, an outer core section and a coupling core section for coupling the middle core section and the outer core section, and a primary winding and a secondary winding are arranged to surround the middle core respectively, a sectional area of the middle core is increased, a number of winds in a radial direction of each of the primary winding and the secondary winding is increased and a number of winds in an axial direction is decreased, and the primary winding and the secondary winding are provided close to each other and a ratio of the sectional area of the middle core to that of the outer core is decreased to be 2:1 or less.

Step-up transformer for magnetron driving

It is an object to decrease an occupied space in a printed board to carry out space saving and to reduce the size of a unit without sacrificing the performance of a transformer and increasing a cost. A transformeris constituted by a bobbinhaving at least a primary windingand a secondary windingwound therearound and a coreand the side surface of the bobbinis provided with a component holding section for holding high-voltage components such as a capacitorand a diodewhich constitute a voltage doubler rectifying circuit for rectifying a high voltage having a high frequency from the secondary winding

Transformer and transformer unit having the same

The present invention provides a boosting transformer for microwave oven, which is low in high-frequency loss, hardly saturated, small in size and easy to produce. The boosting transformer includes a rod-like ferrite core; and primary, secondary and heater windings wound around the rod-like ferrite core and piled up side by side in a direction of an axis of the rod-like ferrite core. It also includes a metal core formed from a long metal thin plate rolled by a plurality of times into a square-ring having one inner diameter larger than each of outer sizes of the primary, secondary and heater windings and the other inner diameter larger than a total size of the three windings piled up side by side, the metal core being arranged opposite to the rod-like ferrite core through a gap so as to be fitted toward the rod-like ferrite core from the outside of the primary, secondary and heater windings.

Growing community of inventors

Yamatokoriyama, Japan

Kenji Yasui