Zone-Free Induction Cooker Coil Detection and Control
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Solution Overview
Problem
Zone-free induction cookers face challenges in distinguishing between a single cooking vessel and multiple vessels, leading to incorrect control zone assignments, which is exacerbated by the need for additional sensing devices that increase hardware complexity and cost.
Innovation Solution
The method involves providing detection signals to induction coils with varying timing or frequencies and measuring response signals to determine if a cooking vessel occupies multiple coils, allowing for accurate control zone assignment without additional sensing devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If discrete sensing devices (optical, capacitive, ultrasonic sensors) are added to detect cooking vessel positions, then the accuracy of vessel detection and control zone assignment is improved, but the hardware complexity and cost increase
Solution Approach 1:
The induction coils themselves perform the sensing function by detecting changes in their electrical characteristics when a cooking vessel is placed on them. The controller monitors parameters such as impedance, resonant frequency, or quality factor of each coil to determine vessel presence and position, eliminating the need for separate sensing devices. This self-service approach resolves the contradiction by using existing components for dual purposes (heating and sensing), thereby improving detection accuracy without increasing hardware complexity.
Solution Approach 2:
The induction coils are designed to serve multiple functions: they act as both heating elements and sensing devices. By monitoring the electrical characteristics of the coils, the system can detect cooking vessel presence, determine their positions, and assign control zones without requiring dedicated sensors. This multi-functionality resolves the technical contradiction by consolidating the sensing function into existing components, avoiding additional hardware while maintaining or improving detection accuracy.
2Adaptability or versatility
If many smaller induction coils are provided to cover the entire cooking surface, then the versatility of vessel placement is improved, but the device complexity and cost increase
Solution Approach 1:
The cooking surface is divided into multiple smaller induction coils arranged in a grid or array pattern, allowing flexible placement of cooking vessels of various sizes and positions. Each coil can be independently controlled, enabling precise heating zones that adapt to the vessel placement. This segmentation resolves the contradiction by providing versatility through multiple small coils while using intelligent control algorithms to manage the complexity, such as grouping adjacent coils into control zones based on detected vessel positions.
Solution Approach 2:
The system dynamically groups adjacent induction coils into control zones based on the detected position and size of cooking vessels. Rather than treating each coil as a fixed independent unit, the controller creates flexible, dynamic zones that adapt to the actual cooking needs. This dynamic approach resolves the contradiction by providing versatility through multiple coils while reducing operational complexity through adaptive zone management, where coils are activated and grouped based on real-time vessel detection.
3Speed
If detection signals are provided to multiple induction coils simultaneously, then the speed of vessel detection is improved, but the accuracy of determining single versus multiple vessels decreases due to signal interference
Solution Approach 1:
The controller provides detection signals to multiple induction coils in a sequential or periodic manner rather than simultaneously, using time-division multiplexing. Each coil is excited in turn with a known test signal, and the response is measured before moving to the next coil. This periodic approach resolves the contradiction by maintaining fast detection speed through systematic sequencing while eliminating signal interference that would occur with simultaneous excitation, thereby preserving measurement precision.
Solution Approach 2:
The detection process operates continuously by rapidly cycling through the induction coils in sequence, creating the effect of simultaneous monitoring without actual simultaneous signal excitation. The quick succession of detection signals to different coils maintains high detection speed while avoiding interference, as each coil's response is measured before the next coil is excited. This continuous cyclic approach resolves the contradiction between speed and accuracy by making the interference-free sequential process fast enough to appear simultaneous.
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 approach enables precise control zone assignment, reducing hardware complexity and cost while improving the accuracy of cooking vessel detection and control, allowing for efficient heating of multiple vessels on a zone-free induction cooker.
Implementation Method 1
Cooking vessels may be placed on the cooking surface where they can be heated by one or more (depending on the arrangement) of the induction coils using electromagnetic induction
Implementation Method 2
providing a detection signal to a first of said induction coils... measuring a response signal from the first induction coil
Data Source
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AI summary
A method and controller (300) for controlling an induction cooker (100) is provided. The induction cooker (100) comprises at least two induction coils (200) for inductively heating cooking vessels (400). A detection signal (500a) is provided to a first of said induction coils (200a) and a detection signal (500b) is provided to a second of said induction coils (200b). A response signal (501a) from the first induction coil (200a) is measured. If the response signal (501a) from the first induction coil (200a) includes an indication (550) of a response signal (501b) generated at the second induction coil (200b) in response to the detection signal (500b) provided to the second induction coil (200b), it is determined that a same cooking vessel (400) occupies both the first induction coil (200a) and the second induction coil (200b).