Panasonic Intellectual Property Management Co., Ltd.

Takashi Takehira

Yuji Yamamoto

Fumitaka Ogasawara

Masashi Kinoshita

Hiroshi Fukuda

An induction heating cooker includes an inverter for supplying a current to a heating coil, a control portion for driving the inverter, an electrostatic capacitance detecting portion for measuring electrostatic capacitance of a plurality of electrodes, and a boiling over detecting portion. The boiling over detecting portion reduces an output of the inverter from a first set value to a second set value after a sensed value of the electrostatic capacitance is within a first variation range (&#x394;V) or more, and returns the output of the inverter to the first set value when a sensed value during a boiling over establishing period (T) performed after the sensed value has reached the first variation range or more and falls within a second variation range (&#x394;V).

Induction heating cooker

The disclosed induction heating cooking device includes a boiling-over detection portion which is adapted to reduce heating output from an inverter to a pre-set value if the amount of change of a capacitance detected by a capacitance detection portion from a reference value (Vo) is equal to or more than an output reduction threshold value (&#x394;V), and further is adapted to stop heating, if the amount of change is equal to or more than an output stop threshold value (&#x394;V). In this case, the output stop threshold value is provided for each of the plurality of the electrodes, which can absorb impedance variations in the plurality of the electrodes formed through pattern printing using conductive films, thereby uniformizing their sensitivity to boiling over in any directions.

Induction heating cooking device

An induction heating cooker includes a boiling over detecting portion that reduces the heating output of an inverter to a predetermined value when a change amount of an electrostatic capacitance detected by a capacitance detecting portion with respect to a reference value is equal to or greater than a threshold value. The boiling over detecting portion stops a heating action or reduces the heating output to a third set value lower than a second set value when a change rate of the capacitance is equal to or greater than a predetermined change rate, and maintains the heating output at the second set value when the change rate of the capacitance is less than the predetermined change rate, during a boiling over determining period started from the time that the change amount of the capacitance with respect to the reference value is equal to or greater than the output reducing threshold value.

Induction cooker and method of operation

In an induction cooking device according to the present invention, a boiling-over detection portion is adapted to perform a heating-output suppression operation, on detecting boiling over, when the capacitances of electrodes have been changed by an amount equal to or more than a predetermined value. Further, the boiling-over detection portion is prevented from performing the heating-output suppression operation, if the boiling-over detection portion detects that the capacitances of the electrodes have been changed by an amount equal to or more than the predetermined value, due to the fact that the heating output of another heating coil in a heating area which is not subjected to boiling-over detection has been changed by an amount equal to or more than a predetermined change width.

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Hyogo, Japan

Takashi Takehira