Magnetron Power Converter Frequency Control to Avoid Resonance
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Solution Overview
Problem
Existing microwave cooking apparatuses face instability in driving magnetrons due to resonance frequency issues, leading to potential damage from surge voltages and inefficient oscillation times.
Innovation Solution
A power converter system that includes a switching unit to convert DC voltage to AC, a driving unit to output high-frequency voltage to a magnetron, an output voltage detector, and a controller to calculate and adjust frequency command values, avoiding resonance frequencies and stabilizing oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the power converter operates at resonance frequency to achieve efficient power transfer, then the power transfer efficiency is improved, but surge voltages occur that can damage circuit elements
Solution Approach 1:
The patent applies dynamics by making the operating frequency adjustable rather than fixed. The controller dynamically changes the frequency command value based on real-time detection of output voltage and identification of resonance frequency. This allows the system to adaptively avoid resonance conditions that cause surge voltages while maintaining efficient operation at optimal frequencies, thus resolving the contradiction between power transfer efficiency and surge voltage prevention.
Solution Approach 2:
The patent implements feedback by using an output voltage detector to monitor the actual output voltage and feed this information back to the controller. The controller compares the detected voltage with reference values to identify resonance frequency and adjusts the frequency command value accordingly. This closed-loop feedback mechanism enables the system to avoid resonance conditions that cause harmful surge voltages while maintaining efficient power transfer.
2Reliability
If the oscillation frequency is adjusted dynamically to avoid resonance, then circuit element protection is improved, but the control complexity increases
Solution Approach 1:
The patent applies self-service by enabling the system to automatically identify its own resonance frequency and adjust its operating parameters without external intervention. The output voltage detector monitors the system's own output, and the controller autonomously compares detected values with reference values to determine resonance conditions and adjust the frequency command value. This self-regulating mechanism protects circuit elements while keeping the control system relatively simple.
Solution Approach 2:
The patent implements parameter changes by modifying the frequency command value based on detected output voltage characteristics. When resonance is detected through voltage pattern recognition, the controller changes the operating frequency parameter to avoid resonance conditions. This parameter adjustment approach provides reliable circuit protection through a relatively simple control mechanism that only requires frequency modulation rather than complex multi-parameter control.
3Stability of the object's composition
If the frequency command value is adjusted in real-time based on output voltage detection, then oscillation stability is improved, but the response time and control precision requirements increase
Solution Approach 1:
The patent applies partial action by implementing frequency adjustment only when resonance conditions are detected, rather than continuously modifying the frequency. The controller monitors output voltage and compares it with reference values, making frequency command value adjustments only when necessary to avoid or escape resonance. This selective adjustment approach maintains oscillation stability while reducing the burden on measurement precision and response time requirements compared to continuous frequency modulation.
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 prevents circuit element damage from surge voltages and shortens oscillation time by dynamically adjusting frequency command values, ensuring stable magnetron operation and efficient microwave generation.
Implementation Method 1
a switching unit to perform switching using a direct current (DC) voltage and to output an alternating current (AC) voltage
Implementation Method 2
the voltage applied to the high-voltage generator is boosted to apply a voltage to a magnetron for generating microwaves
Implementation Method 3
In order to drive the magnetron, high-frequency oscillation should be performed using an AC input voltage
Implementation Method 4
the cooking apparatus using microwaves heats the food using frictional heat generated by irradiating microwaves generated by the magnetron to the food to vibrate molecules constituting the food 2.45 billion times per second
Data Source
AI summary
A power converter and a cooking apparatus including the same are disclosed. The power converter includes a switching unit to perform switching using a direct current (DC) voltage and to output an alternating current (AC) voltage, a driving unit to output a high-frequency voltage to a magnetron based on the AC voltage, an output voltage detector to detect an output voltage flowing to the magnetron, and a controller to calculate a frequency command value based on the detected output voltage, to generate a frequency command value by avoiding a resonance frequency when the calculated frequency command value corresponds to the resonance frequency, and to output the generated frequency command value to the switching unit. Therefore, it is possible to stably perform oscillation.