Capacitance Pan Detection for Induction Hob Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing induction cooking hobs face issues with pan detection routines that result in unnecessary heating and noise, especially in complex configurations, leading to inefficient energy use and potential hazards when non-ferromagnetic objects are placed on the hob.
Innovation Solution
A capacitance-based pan detection method that uses a metallic electrode under the insulating surface to sense the presence of a ferromagnetic pan without activating the induction heating element, allowing continuous detection and quick identification in complex configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pan detection routine is executed by activating the induction heating element, then the presence of a ferromagnetic pan can be detected, but unnecessary heating occurs and energy is wasted when no pan is present
Solution Approach 1:
The patent performs capacitance measurement before activating the induction heating element. A metallic electrode under the insulating surface measures capacitance to detect the presence of a pan in advance, avoiding unnecessary heating and energy waste when no pan is present.
Solution Approach 2:
The patent introduces an intermediary capacitance measurement mechanism between the user action (placing pan) and the heating activation. The capacitance sensor acts as a mediator to detect pan presence without directly heating, separating the detection function from the heating function.
2Reliability
If pan detection routine is executed by activating the induction power converter, then pan presence can be detected, but disturbing noise is generated at start
Solution Approach 1:
The patent extracts the detection function from the power converter activation process. By using a separate capacitance measurement system with metallic electrode, the noisy power converter activation is separated from the quiet capacitance-based pan detection.
3Reliability
If pan detection routine is executed on each coil in complex configurations, then complete pan detection coverage is achieved, but detection time becomes unacceptable
Solution Approach 1:
The patent segments the detection function into multiple independent capacitance measurement points under the insulating surface. Each point can independently detect pan presence, allowing parallel detection across complex configurations without sequential delays.
Solution Approach 2:
The capacitance measurement is performed preliminarily before heating activation, enabling continuous monitoring readiness in complex configurations without adding detection time to the heating start-up process.
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 prevents unnecessary heating, reduces noise, and enhances safety and efficiency by allowing continuous pan detection without power consumption, even in complex hob configurations, while ensuring accurate detection of metallic objects.
Implementation Method 1
detect the ferromagnetic pan by sensing the variation of capacitance measured under the insulating surface
Data Source
Figure 1~4
Figure 3
AI summary
A method for detecting the presence of a cooking vessel on an induction heating element placed below a glass surface comprises detecting through a conductive electrode placed below the glass surface if a cooking utensil is placed on the induction heating element (H) by measuring capacitance, indicating to the user whether the cooking utensil is present on one or more induction heating elements, performing a second detection of the cooking utensil, after activation by the user, by feeding power to said induction heating element (H) and by assessing at least an electrical parameter of a power circuit thereof.