Kabushiki Kaisha Toshiba

Teruya Tanaka

Katsuharu Matsuo

Akira Okada

Koji Murakami

Hitoshi Takimoto

Tatsuya Nakagawa

Mika Morita

Sachiko Endo

Kaoru Maekawa

Yoshiyuki Noguchi

Yutaka Matusmoto

A heating apparatus such as a microwave oven includes a magnetron supplying microwaves into a heating chamber so that food accommodated in it is heated and a microcomputer-based control circuit. The control circuit discriminates the food among three conditions, that is, a first condition in which the food is not wrapped in a wrap film, a second condition in which the food is wrapped in a wrap film, and a third condition belonging neither to the first nor to the second condition. Based on the results of discrimination, the control circuit calculates a remaining heating time.

Microwave oven with food wrap film detecting function

A cooking apparatus for heating food to be served and capable of being operated with utmost simplicity without using and choosing various cooking-mode selection keys so as to achieve superb ease-of-operation. The cooking apparatus includes a cooking chamber for placing and storing food to be heated by the apparatus and a detector for detecting a state of a door attached to the cooking chamber, the door being freely openable and closable against an opening portion of the cooking chamber. An optical sensor, having a plurality of light emitting portions is disposed in a side of the cooking chamber and a plurality of light receiving portions are disposed counter to the light emitting portions. A drive unit is provided for driving the optical sensor and a judgement unit verifies and determines a cooking mode suitable for the food placed in the cooking chamber responsive to a signal from the optical sensor, where the drive unit is activated when the detector detects that the door is closed.

Cooking apparatus operated by a single operational key that

An induction heating cooker comprises an inverter circuit. The inverter circuit has a heating coil and a resonance capacitor that resonates with the heating coil to generate high-frequency electric power with which an object to be heated is inductively heated. The cooker further includes a phase comparator for comparing the phase of a first signal that correlates to the phase of an output voltage of the inverter circuit with the phase of a second signal that correlates with the phase of a current flowing to the resonance capacitor; a phase difference setter for setting the phase difference of the first and second signals; and a frequency controller for controlling an oscillation frequency of the inverter circuit according to a signal from the phase difference comparator to establish the phase difference set by the phase difference setter.

Induction heating cooker with phase difference control

Disclosed is a washing machine which comprises a DC brushless motor to drive a pulsator, an inverter circuit to generate outputs to drive the DC brushless motor by periodically switching input DC voltages with a switching device, an inverter controlling circuit for adjusting outputs of the inverter circuit by controlling the switching operation of the switching device in the inverter circuit, and a detecting mechanism for detecting laundry amount based on a rotating speed of the DC brushless motor and an inverter current flowing through the inverter circuit with the switching device under a constantly controlled state.

Washing machine

In an inverter type high frequency heating apparatus such as an electromagnetic cooker and a microwave oven, an insulated gate bipolar transistor is employed as a switching element. A parallel circuit arranged by a capacitor and a resistor is interposed between a gate electrode of the gate insulated bipolar transistor and a gate driver circuit so as to prevent a power loss, or ringing effect when the gate insulated bipolar transistor is turned off.

High-frequency heating apparatus including ringing effect suppressor for

In an electromagnetic cooking apparatus, low heating power control is carried out by turning ON/OFF a DC power supply circuit, or rectifier circuit, at a commercial frequency lower than an inverting frequency of DC/AC inverter. The electromagnetic cooking apparatus includes: a DC (direct current) power supply for producing DC power from low-frequency AC (alternating current) power; a DC-to-AC inverting circuit coupled to the DC power supply and including a switching element and also a heating coil, for inverting the DC power inputted from the DC power supply into high-frequency AC power so as to heat a metal pan by energizing the heating coil with the high-frequency AC power, thereby electromagnetically inducing eddy currents within the metal pan; a monitoring circuit for monitoring switching conditions of the switching element so as to output a switching condition signal; and an ON/OFF-controlling circuit for turning ON/OFF power supply operation of the DC power supply, or inverting operation of the DC/AC inverter circuit in response to the switching condition signal at a timing period defined by a time constant smaller than a thermal time constant determined by a heat capacity of a metal material of the pan.

Electromagnetic cooker including load control

A temperature controller compares a temperature detection signal outputted from a temperature sensor with a set temperature preliminary set in a temperature setting circuit. According to a result of the comparison and before a zero-cross point of an AC voltage applied from a commercial AC source to a heating member, a driving circuit of the temperature controller outputs a driving signal to a thyristor to turn ON the thyristor at the zero-cross point. Then the AC voltage is applied to the heating member via the thyristor. Since the determination of turning ON or OFF the thyristor is made before the zero-cross point of the AC voltage applied through the thyristor, the thyristor may surely be turned ON or OFF at the zero-cross point to prevent electromagnetic wave noises from occurring.

Temperature controller

An induction heated cooking apparatus for heating a removable cooking vessel having one of high resistance and a low resistance. The apparatus includes a power source for supplying a power source voltage, an induction heating device responsive to the power source for inducing an eddy current in the cooking vessel, including an induction coil device for exposing the vessel to a magnetic field for inducing the eddy current and a device for generating a high frequency current for inducing the magnetic field, an impedance state detection circuit for detecting the high frequency current, a frequency state detection circuit for detecting the frequency of the high frequency current and a control circuit for controlling the induction heating device in response to the impedance state detection circuit and the frequency state detection circuit.

Induction heated cooking apparatus

An electromagnetic induction cooking apparatus having a heating coil, an inverter for supplying an input power to the coil, and a load-identifying circuit. The coil comprises two coils elements. The first coil elements has a first number (N.sub.1) of turns, and the second coil element has a second number (N.sub.2) of turns. The load-identifying circuit identifies the material of a load (e.g., a pan) and selects the first coil element or the second coil element in accordance with the material of the load. When the circuit selects the first coil element, a first DC voltage is applied to the inverter, and the inverter generates and supplies a first high-frequency current of frequency f.sub.1 to the first coil element. When the circuit selects the second coil element, a second DC voltage is applied to the inverter, and the inverter generates and supplies a second high-frequency current of frequency f.sub.2 to the second coil element. The ratio of N.sub.2 to N.sub.1 (N.sub.2 /N.sub.1) is about four to six times the product of the ratio of E.sub.2 to E.sub.1 (E.sub.2 /E.sub.1 ) and the (-1/4)th power of the ratio of f.sub.2 to f.sub.1 (f.sub.2 /f.sub.1).

Electromagnetic induction cooking apparatus capable of providing a

An object to be heated, such as a cooking utensil or vessel, is placed on a top plate. An inventer has a resonating circuit comprising an induction heating coil arranged below the top plate and a resonating capacitor connected to the coil, and a circuit for supplying high-frequency power to the resonating circuit in order to generate a high-frequency magnetic field from the induction heating coil and to induce an eddy current in the object to be heated. An inverter power level control data generating unit outputs inverter power level control data according to the relationship between the high-frequency power from the inverter circuit and a repulsion force acting on the object to be heated, based on the high-frequency power. The inverter power level control data is data for controlling the level of the high-frequency power from the inverter circuit so as to prevent the object to be heated from floating over a placing surface of the top plate, due to the repulsion force. A control unit feeds back the inverter power level control data from the control data generating unit to the inverter circuit.

Growing community of inventors

Yokohama, Japan

Teruya Tanaka