Magnetron Anode Current Monitoring for Microwave Abnormality Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing high-frequency heating apparatuses, such as microwave ovens, face challenges in accurately detecting and preventing overheating and empty heating states, which can lead to thermal breakdown of components like the magnetron and high-voltage diodes, due to inadequate temperature detection methods that are costly, complex, and lack sensitivity.
Innovation Solution
A state detection device that monitors the anode current of the magnetron, using threshold value control and changing value detection control to determine the operating state by reading the anode current multiple times, allowing for accurate identification of abnormal states like empty heating or overheating, and triggering appropriate actions to prevent component damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thermistor is placed near the magnetron to detect temperature, then temperature detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses the anode current as an intermediary parameter to indirectly detect the operating state and temperature conditions of the magnetron. Instead of placing a thermistor directly near the magnetron, the system monitors the anode current which changes in response to temperature variations and operating conditions, providing a non-intrusive detection method that avoids adding complex temperature sensing hardware near sensitive components
Solution Approach 2:
The patent replaces the mechanical/physical temperature detection system (thermistor placement) with an electrical parameter-based detection system. By substituting direct temperature measurement with anode current monitoring, the system eliminates the need for physical temperature sensors near the magnetron, thereby reducing device complexity while maintaining detection capability
2Reliability
If multiple detection methods are implemented to accurately detect abnormal states, then detection reliability is improved, but device complexity increases
Solution Approach 1:
The patent makes the anode current detection system multi-functional by using it to detect multiple abnormal operating states including empty heating, overheating, and magnetron failures. A single detection parameter (anode current) serves multiple diagnostic purposes, eliminating the need for separate detection systems for each abnormal condition and thereby maintaining reliability without increasing complexity
Solution Approach 2:
The patent utilizes changes in the anode current parameter to detect different abnormal operating states. By monitoring variations in anode current characteristics under different failure conditions, the system achieves reliable detection of multiple abnormalities using a single parameter, avoiding the need for multiple independent detection systems
3Device complexity
If simple detection methods are used, then device complexity is reduced, but measurement precision and sensitivity deteriorate
Solution Approach 1:
The patent implements a feedback mechanism where the detected anode current values are continuously monitored and compared against expected ranges. The system uses the feedback from current measurements to identify deviations indicating abnormal states, enhancing detection sensitivity without requiring complex hardware. The feedback loop enables simple circuitry to achieve precise detection through intelligent processing of current parameter variations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides reliable and accurate detection of abnormal operating states, preventing overheating and ensuring the safety and longevity of high-frequency heating apparatus components, while simplifying the detection process and reducing costs.
Implementation Method 1
an anode current detection portion which detects an anode current of the magnetron
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An operating state detection technique is provided which makes it possible to accurately detect an abnormality of a high-frequency heating apparatus. An anode current detected by the anode current detection resistor 40 of a magnetron is inputted into the A/D converter terminal of a microcomputer 27 on a control panel circuit board side. The current is subjected to an analog-to-digital conversion to thereby obtain an anode voltage IaDC value. The microcomputer 27 determines an operating state based on a plurality of the anode voltage IaDC values thus read. Further, the microcomputer 27 obtains a summed value of the IaDC values corresponding to one period of the revolution of rotary antennas 68, 69 to thereby determines the operating state of the high-frequencyheating apparatus 100 based on the summed value. According to the aforesaid IaDC value reading method, it makes it possible to accurately detect an abnormality without an erroneous operation also in correspondence to the change of the feeding distribution. Further, the microcomputer 27 changes, in accordance with the set output of the high-frequency heating apparatus, a threshold value used for determining the abnormality and a changing value (increasing amount) from the start of the operation with respect to the change of the output of the apparatus and the operating state of a heated subject etc., whereby it makes it possible to accurately detect an abnormality without an erroneous operation.