Induction Cooker Coil Block Detection for Magnetic Interference
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Solution Overview
Problem
Induction heating cookers with densely arranged small-sized heating coils suffer from magnetic field interference, leading to container position detection errors and unnecessary power consumption when trying to detect the position of a container on the cooking plate.
Innovation Solution
The induction heating cooker divides the heating coils into blocks and alternately supplies high-frequency voltage to each block, using sensors to detect the current flowing through each coil and determining the container's position based on a predetermined current value, thereby reducing magnetic field interference and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-frequency current is simultaneously supplied to all heating coils to detect container position, then container position detection can be performed, but magnetic field interference occurs between adjacent heating coils leading to detection errors
Solution Approach 1:
The heating coils are divided into multiple blocks, and high-frequency current is supplied to each block alternately rather than simultaneously. This segmentation approach reduces magnetic field interference between adjacent coils while still enabling comprehensive container position detection across the entire cooking surface.
Solution Approach 2:
High-frequency current is supplied to different heating coil blocks in periodic alternation. Each block is activated sequentially for detection purposes, allowing the system to scan the entire cooking surface while minimizing interference by ensuring that not all coils are active at the same time.
2Area of stationary object
If small-sized heating coils are densely arranged below the entire cooking plate surface, then heating coverage is improved, but magnetic field interference between adjacent coils increases
Solution Approach 1:
The densely arranged heating coils are organized into distinct blocks that are activated alternately. This segmentation maintains the dense arrangement for comprehensive heating coverage while reducing interference by ensuring that only a subset of coils is active at any given moment during detection operations.
Solution Approach 2:
The system employs periodic activation of different coil blocks, switching between them in sequence. This allows the densely arranged coils to provide full-area heating capability while minimizing magnetic field interference during container position detection by activating only one block at a time.
3Reliability
If container position detection error occurs, then unnecessary heating coils are driven, but this leads to unnecessary power consumption and potential inverter damage
Solution Approach 1:
By dividing heating coils into blocks and detecting container position using only the currently active block, the system reduces false detections caused by magnetic field interference. This ensures that only heating coils with actual containers are activated, preventing unnecessary power consumption and protecting inverters from damage.
Solution Approach 2:
The system uses current sensing to detect changes in electrical characteristics when a container is placed on a heating coil. This feedback mechanism allows accurate identification of container positions, ensuring that power is supplied only to coils that actually need heating, thereby reducing wasted energy and preventing inverter damage from incorrect operation.
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 enhances container position detection accuracy and prevents unnecessary power consumption by minimizing magnetic field interference between adjacent heating coils, ensuring accurate heating coil identification and efficient energy use.
Implementation Method 1
an induction heating cooker supplies high-frequency current to a heating coil so as to generate a strong high-frequency magnetic field in the heating coil and generates eddy current in a cooking container (hereinafter, simply referred to as a container) magnetically coupled to the heating coil through the high-frequency magnetic field such that the container is heated by Joule's heat
Implementation Method 2
the container is heated by Joule's heat so as to cook food
Implementation Method 3
using sensors to detect the current flowing through each coil and determining the container's position based on a predetermined current value
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
An induction heating cooker includes a plurality of heating coil blocks including one or more heating coils, a plurality of inverters to supply a high-frequency voltage to each of the heating coils, and a controller to control operations of the plurality of inverters to alternately supply the high-frequency voltage to each heating coil block and detect a heating coil, on which a container is placed, from among the heating coils belonging to each of the plurality of heating coil blocks. Using this configuration, it is possible to reduce the influence of magnetic field interference between adjacent heating coils when detecting the position of the container and to increase container position detection accuracy.