Induction Cooktop Temperature Control via Coil Inductance Fusion
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Solution Overview
Problem
Induction cooking appliances face challenges in accurately estimating the temperature of cookware due to variations in materials and conditions, leading to inefficiencies in cooking control.
Innovation Solution
The induction cooking appliance utilizes a combination of temperature sensors and induction coil inductance measurements, processed through a complementary filter, to estimate cookware temperature by blending thermal and electrical parameters, enhancing accuracy and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only temperature sensor is used for cookware temperature estimation, then the measurement is simple, but the accuracy is insufficient due to variations in materials and conditions
Solution Approach 1:
The patent combines temperature sensor measurements with induction coil inductance measurements to estimate cookware temperature. By merging thermal data (from temperature sensor) and electrical data (from inductance measurement), the system achieves more accurate temperature estimation than either method alone, resolving the contradiction between measurement simplicity and accuracy.
Solution Approach 2:
The patent introduces a complementary filter as an intermediary processing mechanism that blends the temperature sensor signal and inductance-based temperature estimate. This filter acts as a mediator to optimally combine the two measurement approaches, achieving high accuracy while maintaining manageable system complexity through a unified processing framework.
2Speed
If temperature control is based on cook surface temperature only, then the control is simple, but the responsiveness to cookware temperature changes is slow
Solution Approach 1:
The patent implements feedback control by continuously measuring inductance changes and using them to estimate cookware temperature in real-time. The inductance-based temperature estimate provides immediate feedback about cookware temperature conditions, enabling rapid responsiveness to temperature changes while the complementary filter maintains control algorithm manageability.
3Speed
If inductance measurement is used for temperature estimation, then the responsiveness improves, but the measurement precision varies with material conditions
Solution Approach 1:
The patent merges inductance-based temperature estimation with temperature sensor-based estimation through a complementary filter. This combination leverages the responsiveness of inductance measurements while compensating for their material-dependent precision variations using the more stable temperature sensor data, achieving both speed and accuracy.
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 provides enhanced temperature estimation and control, allowing for more precise cooking by adjusting power supply based on real-time cookware conditions, improving cooking efficiency and accuracy.
Implementation Method 1
an induction coil below the cook surface and configured to heat cookware on the cook surface
Implementation Method 2
a temperature sensor coupled to the cooktop and configured to provide a temperature signal indicative of a temperature of the cook surface
Data Source
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AI summary
An induction cooking appliance (10) includes a cooktop (12) having a cook surface (14), an induction coil (16) below the cook surface (14) and configured to heat cookware (18) on the cook surface (14), a temperature sensor (20, 22) coupled to the cooktop (12) and configured to provide a temperature signal indicative of a temperature of the cook surface (14), and control circuitry (26) in communication with the induction coil (16) and the temperature sensor. The control circuitry (26) is configured to measure an inductance (L) of the induction coil (16), determine a first temperature estimate based on the inductance (L), determine a second temperature estimate based on the temperature signal, estimate a temperature of the cookware (18) based on the first temperature estimate and the second temperature estimate, compare the estimated temperature of the cookware (18) to a target temperature set by a user, and control power supplied to the induction coil (16) based on the comparison.