Differential Detection Coils for Quiet, Precise Induction Cooktop Sensing
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Solution Overview
Problem
Induction cooktops face challenges in accurately detecting cookware items above the cooking zones due to the limited information provided by traditional high-energy electromagnetic field stimulation, which generates audible noise and lacks precise location detection.
Innovation Solution
A cooking article detection system using an array of detection coils arranged in differential pairs, driven by a low-voltage, high-frequency signal, measures voltage across the coils to identify cookware presence or absence by detecting changes in resistance and inductance, allowing for quiet and precise detection without interference from external electromagnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional high-energy electromagnetic field stimulation is used for cookware detection, then detection capability is achieved, but audible noise is generated and location precision is limited
Solution Approach 1:
The patent changes the parameters of the detection signal from high-energy to low-voltage and high-frequency. This parameter transformation allows the system to detect cookware presence and location without generating audible noise, as the lower voltage prevents mechanical vibration of the cookware that causes clicking sounds while the high frequency enables precise electromagnetic coupling detection
Solution Approach 2:
The patent divides a single detection coil into multiple differential pairs of coils arranged in a grid pattern. Each differential pair consists of two coils wound in opposite directions that are positioned close together. This segmentation allows the system to achieve both noise-free operation and improved spatial resolution by measuring voltage differences between adjacent coils to determine cookware location
2Reliability
If traditional high-energy electromagnetic field stimulation is used for cookware detection, then detection capability is achieved, but location precision is limited
Solution Approach 1:
The patent segments the detection system into multiple differential coil pairs arranged in a grid, where each pair provides localized measurement capability. By comparing voltage differences between adjacent coils in the differential pairs, the system can precisely determine the location of cookware on the cooktop surface, transforming a single coarse detection point into multiple precise measurement points
Solution Approach 2:
The patent implements local quality by having different regions of the cooktop monitored by specific differential coil pairs. Each differential pair is optimized to detect cookware in its local area, and the collective response of all differential pairs provides comprehensive spatial information about cookware placement across the entire cooktop surface
3Object-generated harmful factors
If differential detection coils are used with low-voltage high-frequency signal, then noise reduction and location precision are improved, but system complexity increases
Solution Approach 1:
The patent merges multiple detection functions into a unified differential coil structure. Each differential pair combines two coils wound in opposite directions to simultaneously achieve noise cancellation through differential measurement and improved sensitivity through constructive interference of magnetic fields. The grid arrangement of multiple differential pairs is merged to provide comprehensive coverage while sharing common control and signal processing infrastructure
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 system provides accurate and quiet detection of cookware on induction cooktops, enabling precise control of heating based on cookware location and size, even during power delivery, with robustness against external noise and manufacturing variations.
Implementation Method 1
cooking article detection is typically performed by stimulating the cookware item with a large electromagnetic field generated by the power-delivery coils
Implementation Method 2
driving the first and second detection coils, simultaneously, with a low-voltage, high frequency detection signal, and measuring a voltage across the first and second detection coils
Data Source
AI summary
A cooking article detection system for an induction cooktop having a first power-delivery induction coil includes a first detector coil overlying the first power-delivery induction coil and including a first conductive element revolving continuously around a centroid in a first tangential direction to define a shape of the first coil that extends in a first linear direction and a second linear direction along a plane and a second detector coil overlying the first power-delivery coil and including a second conductive element connected with the first detector coils and revolving continuously around a centroid in a second tangential direction, opposite the first tangential direction. The second detector coil is linearly arranged with the first detector coil and is spaced apart therefrom in the second linear direction. A controller drives the first and second detection coils, simultaneously, with a low-voltage, high frequency detection signal, and measures a voltage across the first and second detection coils to identify a cooking article on the induction cooktop.