Induction Cooker Multi-Coil Frequency Control for Composite Material Heating
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Solution Overview
Problem
Existing induction heating cookers fail to control power distribution based on the material of the heating object, leading to uneven heating temperatures and reduced efficiency when heating composite materials, such as frying pans with a metal-coated bottom, where the magnetic material is only attached to the center and not the curved outer peripheral portion.
Innovation Solution
An induction heating cooker with multiple coils and inverter circuits that determine the material of the heating object and adjust the frequency of high-frequency currents supplied to each coil, ensuring that the frequency is higher for non-magnetic materials and stopping power to the outer peripheral portion to prevent unnecessary heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the induction heating cooker supplies electric power to all heating coils uniformly, then the device complexity is low, but the heating temperature becomes uneven and heating efficiency reduces when heating composite material objects
Solution Approach 1:
The heating system is divided into multiple independent heating coils (first, second, and third coils) with separate inverter circuits, allowing each coil to be controlled independently based on the material detected above it. This segmentation enables differentiated power distribution to achieve uniform heating of composite material objects without requiring complex centralized control.
Solution Approach 2:
Each heating coil is assigned a different operating frequency based on the material type detected above it (magnetic or non-magnetic). This local quality adjustment allows the system to optimize heating effectiveness for each specific material type in different spatial zones, ensuring uniform overall heating while maintaining relatively simple control logic.
2Productivity
If the induction heating cooker uses a single frequency for all heating coils, then the device complexity is low, but the heating efficiency reduces when heating non-magnetic materials
Solution Approach 1:
The system changes the operating frequency parameter of each heating coil based on the material type detected above it. Magnetic materials are heated at one frequency while non-magnetic materials are heated at a different frequency, optimizing heating efficiency for each material type. This parameter adaptation is achieved through simple conditional control logic rather than complex systems.
3Area of stationary object
If the induction heating cooker supplies power to the outer peripheral coil, then the area covered is increased, but the heating efficiency reduces due to unnecessary power input to non-heating areas
Solution Approach 1:
The system extracts or removes power supply to the third heating coil when no magnetic material is detected above it, preventing energy waste in areas where heating is not needed. This selective power extraction maintains the physical infrastructure for potential future use while eliminating current energy losses, achieving a balance between coverage capability and energy efficiency.
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 solution allows for even heating temperatures and improved efficiency by tailoring the induction heating to the material of the heating object, reducing power input to non-heated areas and enhancing usability.
Implementation Method 1
an induction heating cooker includes a first coil, a second coil arranged outside the first coil, a third coil arranged outside the second coil, a first inverter circuit configured to supply a first high-frequency current to the first coil, a second inverter circuit configured to supply a second high-frequency current to the second coil
Implementation Method 2
the controller operates the first inverter circuit and the second inverter circuit, and stops an operation of the third inverter circuit, and controls such that a frequency of the second high-frequency current is higher than a frequency of the first high-frequency current
Data Source
AI summary
An induction heating cooker includes a first coil, a second coil, a third coil, a first inverter circuit configured to supply a first high-frequency current to the first coil, a second inverter circuit configured to supply a second high-frequency current to the second coil, a third inverter circuit configured to supply a third high-frequency current to the third coil, a controller, and a load determining unit configured to determine a material of a heating object, wherein when a material of the heating object placed above the first coil is a magnetic material and a material of the heating object placed above the second coil includes a non-magnetic material, the controller operates the first inverter circuit and the second inverter circuit, and stops an operation of the third inverter circuit, and controls such that a frequency of the second high-frequency current is higher than a frequency of the first high-frequency current.