Induction Heating Cooker

• US 20070278216A1
• Filed: 04/18/2006
• Published: 12/06/2007
• Est. Priority Date: 05/27/2005
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Tominaga, Hiroshi, Watanabe, Kenji, Mae, Chika
• Granted Patent: US 7,446,287 B2
• Time in Patent Office: Days
• US Class Current: 219/627
• CPC Class Codes: H05B 2213/07 Heating plates with temperature control means
• CPC Class Codes: H05B 6/062 for cooking plates or the like

Abstract

An induction heating cooker has a top plate, a heating coil, an inverter circuit, a pot type discriminator, a non-magnetic-metal buoyancy reducing plate having a high electrical conductivity, an infrared sensor, a temperature calculator, and a controller. The pot type discriminator judges whether a pot is made of a non-magnetic metal material having a high electrical conductivity, or a magnetic metal material or a non-magnetic metal lower in electrical conductivity than aluminum. The temperature calculator calculates the temperature of the pot from an output from the infrared sensor that detects infrared radiation from the pot. The controller controls an output from the inverter circuit according to a calculated temperature by the temperature calculator, and, when the pot is judged to be made of a non-magnetic metal material by the pot type discriminator, nullifies temperature detection made by the temperature calculator.

Claims

1. An induction heating cooker comprising:

a top plate configured to place a cooking pot thereon,

a heating coil disposed underneath the top plate,

an inverter circuit configured to supply a high frequency current to the heating coil,

a pot type discriminator configured to judge whether the cooking pot is made of a non-magnetic metal material having a high electrical conductivity comparable to or higher than that of aluminum, or a magnetic metal material or a non-magnetic metal lower in electrical conductivity than aluminum,

a buoyancy reducing plate made of a non-magnetic metal having a high electrical conductivity comparable to or higher than that of aluminum, the buoyancy reducing plate being disposed between the top plate and the heating coil and being configured to reduce a buoyancy effective to the cooking pot during induction-heating the cooking pot, an infrared sensor configured to detect an infrared radiation from the cooking pot,

a temperature calculator configured to calculate a temperature of the cooking pot from an output of the infrared sensor, and

a controller configured to control an output of the inverter circuit in accordance with a temperature calculated at the temperature calculator, and to nullify a temperature detection made by the temperature calculator when the pot type discriminator judges that the cooking pot is made of a non-magnetic metal material having a high electrical conductivity comparable to or higher than that of aluminum.

2. The induction heating cooker according to claim 1, further comprising a first temperature sensor configured to measure a temperature of the cooking pot by a heat conduction via the top plate.

3. The induction heating cooker according to claim 2, wherein,

the controller suppresses high frequency current to be supplied to the heating coil or interrupts a heating operation when at least either one of a temperature calculated at the temperature calculator and a temperature detected at the first temperature sensor satisfies respective predetermined conditions.

4. The induction heating cooker according to claim 2 further comprising a second temperature sensor configured to measure a temperature of the buoyancy reducing plate, wherein,

the pot type discriminator judges that the cooking pot is made of a non-magnetic metal material having a high electrical conductivity comparable to or higher than that of aluminum when a temperature measured at the first temperature sensor is lower than a first temperature and a temperature measured at the second temperature sensor is higher than a second temperature that is higher than the first temperature.

5. The induction heating cooker according to claim 1 further comprising a second temperature sensor configured to measure a temperature of the buoyancy reducing plate, wherein

the pot type discriminator judges that the cooking pot is made of a non-magnetic metal material having a high electrical conductivity comparable to or higher than that of aluminum when a change of temperature measured at the second temperature sensor is greater than a certain specific value.

6. The induction heating cooker according to claim 1, wherein

the pot type discriminator judges based on an output from the inverter circuit whether the cooking pot is made of a non-magnetic metal material having a high electrical conductivity comparable to or higher than that of aluminum, or a magnetic metal material or a non-magnetic metal material lower in electrical conductivity than aluminum.

7. The induction heating cooker according to claim 1, wherein

in a case where the pot type discriminator judges that the cooking pot is made of a non-magnetic metal material having a high electrical conductivity comparable to or higher than that of aluminum and an output from the inverter circuit is lower than a certain specific value, the controller stops nullifying the temperature detection made by the temperature calculator, and controls the inverter circuit in accordance with the temperature calculated at the temperature calculator.

8. The induction heating cooker according to claim 1, further comprising a informer configured to exhibit a nullified status during the controller is nullifying the temperature detected by the temperature calculator.

9. The induction heating cooker according to claim 1, wherein

the controller performs an automatic cooking by controlling an output from the inverter circuit based on a temperature calculated at the temperature calculator in accordance with a certain specific algorithm.

10. The induction heating cooker according to claim 9, wherein

the controller blocks an automatic cooking scheme when the pot type discriminator judges that the cooking pot is made of a non-magnetic metal material having a high electrical conductivity comparable to or higher than that of aluminum.

11. The induction heating cooker according to claim 10, further comprising an informer configured to exhibit that the controller is blocking the automatic cooking scheme when the controller is blocking an automatic cooking scheme.

12. The induction heating cooker according to claim 9, wherein

when the pot type discriminator judges that the cooking pot is made of a non-magnetic metal material having a high electrical conductivity comparable to or higher than that of aluminum, the controller limits a greatest output of the inverter circuit to be lower than a certain specific value.

13. The induction heating cooker according to claim 9, wherein

the controller blocks starting of an automatic cooking scheme for a certain specific time after heating of a cooking pot made of a non-magnetic metal material having a high electrical conductivity comparable to or higher than that of aluminum is finished.

14. The induction heating cooker according to claim 13, further comprising a time counter configured to count a time of heating a cooking pot while the pot type discriminator is judging that the cooking pot is made of a non-magnetic metal material having a high electrical conductivity comparable to or higher than that of aluminum, wherein

the controller changes a blocking time before starting of a forthcoming automatic cooking scheme in accordance with a time counted at the time counter.

15. The induction heating cooker according to claim 13, further comprising a informer configured to exhibit that the controller is blocking an automatic cooking scheme when the controller is blocking an automatic cooking scheme.