Induction Cooktop Activity Detection via Interference Signal
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Solution Overview
Problem
Existing induction cooking appliances face challenges in accurately and safely determining the activity state of heating units, leading to potential safety risks due to time-consuming and error-prone methods.
Innovation Solution
The cooking appliance device incorporates a sensor unit to detect signals influenced by the heating unit, using an interference signal to determine the activity state, and a control unit to check the switching unit's function, allowing for quick and reliable activity determination without additional sensors, thus enhancing operational safety and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature determination from main signal is used, then activity state can be determined, but it is time-consuming and error-prone
Solution Approach 1:
The patent converts the harmful interference signal, which was previously discarded as noise, into a useful measurement parameter for determining heating unit activity state. By evaluating the amplitude and frequency characteristics of the interference signal generated during PWM switching, the system achieves fast and accurate activity detection without the time delays associated with temperature-based methods.
2Measurement precision
If additional sensor units are added for activity detection, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent makes the existing sensor unit multi-functional by enabling it to extract both main signal information and interference signal information from the same sensor element. This allows the single sensor unit to perform multiple functions: temperature monitoring, activity state detection, and switching unit function verification, eliminating the need for additional dedicated sensors.
Solution Approach 2:
The system uses its own operational characteristics (the interference signal generated during PWM switching) as the measurement source for activity detection. This self-service approach means the heating unit's own switching activity creates the signal used to monitor its state, eliminating dependency on external or additional sensing mechanisms.
3Reliability
If switching unit function is not verified, then device complexity is reduced, but operational safety decreases
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously monitors the interference signal characteristics and compares them against expected values for proper switching unit operation. This feedback loop enables automatic detection of switching unit malfunctions and triggers appropriate safety responses, enhancing operational reliability through intelligent monitoring rather than additional hardware.
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 enables a high level of operational safety, flexibility, and cost-effectiveness by accurately determining the activity state of heating units using interference signals, reducing the probability of malfunctions and allowing for efficient operation across various cooking appliances.
Implementation Method 1
In an operating state, a sensor unit (14) of the cooking appliance detects a main signal and an interference signal superimposed on the main signal, using a sensor element (18) designed as a resistance sensor
Implementation Method 2
the heating unit could be an induction heating unit and specifically designed to supply energy to the cooking vessel in the form of an alternating electromagnetic field
Implementation Method 3
In an operating state, a heating unit (12) heats a cooking vessel
Data Source
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Figure 3~5
AI summary
The invention relates to a cooking appliance (10), in particular an induction cooktop, with at least one heating unit (12) and with at least one sensor unit (14) which is provided for detecting at least one signal influenced by the heating unit (12). In order to provide a generic device with improved properties with regard to activity determination, it is proposed that the cooking appliance (10) has at least one control unit (16) which is provided for determining at least one activity level of the heating unit (12) from an interference signal superimposed on a main signal.