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

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.