State detection device for detecting abnormal operation of a high-frequency magnetron heating apparatus

• US 7,863,887 B2
• Filed: 12/26/2006
• Issued: 01/04/2011
• Est. Priority Date: 12/26/2005
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Moriya, Hideaki, Sakai, Shinichi, Suenaga, Hauo, Shirokawa, Nobuo, Kinoshita, Manabu
• Primary Examiner(s): Nguyen; Vinh P
• Application Number:
  US12/159,012
• Publication Number:
  US 20090230949A1
• Time in Patent Office: 1,470 Days
• Field of Search: None
• US Class Current: 324/120
• CPC Class Codes: H05B 2206/043 Methods or circuits intended to extend the life of the magnetron
• CPC Class Codes: H05B 6/666 Safety circuits emergency protective circuits in general H02H

Abstract

A device utilizing an operating state detection technique is provided which makes it possible to accurately detect an abnormality of a high-frequency heating apparatus.

Claims

1. A state detection device for detecting an operating state of a high-frequency heating apparatus including a magnetron for generating microwave;

comprising;

an anode current input portion which inputs a detected anode current of the magnetron; and

a determination portion which reads a corresponding value corresponding to the anode current inputted by the anode current input portion for a plurality of times during a predetermined time period and determines the operating state of the high-frequency heating apparatus based on a plurality of the corresponding values, wherein

the determination portion determines the operating state of the high-frequency heating apparatus based on (1) a threshold value control based on a number of times where the corresponding value larger than a predetermined threshold value is read continuously and/or (2) a changing value detection control based on a changing value per unit time of the corresponding value calculated by the reading of plural times.

2. A state detection device according to claim 1, wherein

when the number of times reaches a predetermined number of times or more in (1) the threshold value control or when the changing value exceeding a predetermined threshold value is calculated for a predetermined number of times or more in (2) the changing value detection control, the determination portion determines that the operating state of the high-frequency heating apparatus is not normal to thereby stop an operation of the high-frequency heating apparatus or reduce an output thereof.

3. A state detection device according to claim 1, wherein the anode current input portion is constituted by an A/D converter terminal which subjects an anode voltage that is the corresponding value to an analog-to-digital conversion.

4. A state detection device according to claim 1, wherein the determination portion determines whether the operating state of the high-frequency heating apparatus is a normal state, an empty heating state or an overheating state by a load based on the changing value under (2) the changing value detection control.

5. A state detection device according to claim 4, further comprising a buzzer which warms the empty heating state and the overheating state by different buzzer sounds, respectively.

6. A state detection device according to claim 1, wherein (2) the changing value detection control is performed when the number of times does not exceed the predetermined number of times in (1) the threshold value control.

7. A high-frequency heating apparatus, comprising:

the magnetron, an anode current detection portion which detects the anode current, an inverter portion which controls the magnetron, and the state detection device according to claim 1.

8. A high-frequency heating apparatus according to claim 7, wherein the anode current detection portion is configured by an anode current detection resistor which is disposed in a path for grounding the inverter portion.

9. A high-frequency heating apparatus according to claim 7, wherein the state detection device outputs a command for making the anode current constant to the inverter portion when the state detection device is determined that the operating state of the high-frequency heating apparatus is not normal.

10. A state detection method for detecting an operating state of a high-frequency heating apparatus including a magnetron for generating microwave;

comprising;

a step of inputting a detected anode current of the magnetron; and

a step of reading a corresponding value corresponding to the anode current thus inputted for a plurality of times during a predetermined time period and determining the operating state of the high-frequency heating apparatus based on a plurality of the corresponding values, wherein

the determination step determines the operating state of the high-frequency heating apparatus based on at least one of (1) a threshold value control based on a number of times where the corresponding value larger than a predetermined threshold value is read continuously and (2) a changing value detection control based on a changing value per unit time of the corresponding value calculated by the reading of a plural times.