Induction Cooker Controller Frequency Management
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Solution Overview
Problem
Induction heating cookers face issues with pot noise due to differences in driving frequencies between multiple heating coils, leading to user discomfort and reduced usability.
Innovation Solution
The induction heating cooker incorporates a controller with a conduction time detector to adjust the driving frequencies of inverter circuits based on the distance between heating coils, ensuring that either the same frequency is maintained or reduced to minimize audible noise, thereby improving usability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the driving frequency of the inverter circuit is reduced to the optimum driving frequency to suppress pot noise, then the pot noise caused by frequency differences is suppressed, but the driving frequency becomes fixed to an audible range causing user discomfort
Solution Approach 1:
The patent applies dynamics by making the driving frequency adjustable rather than fixed. The controller dynamically changes the driving frequency based on the conduction period of the switching unit, allowing the system to adapt between suppressing pot noise and avoiding audible ranges for user comfort.
Solution Approach 2:
The patent changes the driving frequency parameter based on the conduction period of the switching unit. When the conduction period exceeds a predetermined threshold, the controller adjusts the driving frequency to a value different from the optimum, thereby changing the operational parameters to balance noise suppression with user comfort.
2Loss of energy
If the driving frequency is reduced to suppress pot noise, then electrical loading of switching means is reduced, but the driving frequency becomes fixed causing user discomfort
Solution Approach 1:
The system dynamically adjusts the driving frequency based on real-time conduction period measurements, allowing it to optimize electrical loading while avoiding fixed audible frequencies that cause user discomfort.
Solution Approach 2:
The controller uses feedback from the conduction period detector to continuously monitor and adjust the driving frequency, ensuring optimal electrical loading while preventing the system from being locked into uncomfortable audible frequency ranges.
3Power
If multiple heating coils are operated simultaneously with different driving frequencies to optimize input power, then maximum input power is obtained, but pot noise is generated due to frequency differences
Solution Approach 1:
The patent changes the driving frequency parameter of inverter circuits based on conduction period measurements. By adjusting frequencies dynamically rather than using fixed different frequencies, the system maintains optimal power input while suppressing pot noise through coordinated frequency management.
Solution Approach 2:
The system uses conduction period feedback to coordinate the driving frequencies of multiple inverter circuits, allowing them to operate at optimal power levels while preventing the frequency differences that cause pot noise.
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
This configuration effectively suppresses pot noise caused by frequency differences, enhancing user experience and usability by allowing flexible placement of heating targets and efficient use of space.
Implementation Method 1
a plurality of heating coils which are disposed under the top plate and heat the heating target object
Implementation Method 2
induction heating is performed with respect to the heating target object
Implementation Method 3
a switching unit which switches current of a resonance circuit
Data Source
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AI summary
A controller drives an inverter circuit at the same frequency in a case where a plurality of heating target objects are simultaneously heated by heating coils which are adjacent with each other. In addition, the controller includes a conduction time detector for detecting a conduction period of time of a switching element of the inverter circuit. In a case where the conduction period of time is equal to or less than a predetermined value, the controller does not switch a driving frequency of the switching element, and in a case where the conduction period of time becomes longer than the predetermined value, the controller makes the driving frequency of the inverter circuit be decreased and drives the inverter circuit to heat the heating target object.