Induction Cooktop Temperature Estimation Using Complementary Sensing
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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 temperature control.
Innovation Solution
The system employs a complementary filter that blends electrical and thermal estimates using inductance and temperature sensors, with a controller adjusting the bias between these estimates based on conditions like food insertion or steady states, enhancing temperature estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single temperature sensing method is used, then the device complexity is reduced, but the temperature estimation accuracy deteriorates due to variations in cookware materials and conditions
Solution Approach 1:
The patent combines electrical sensing (inductance measurement) and thermal sensing (temperature sensor) methods into a unified temperature estimation system. The controller integrates signals from both the induction coil inductance and the temperature sensor to produce a complementary temperature estimate, thereby improving accuracy without requiring a single complex sensing mechanism
Solution Approach 2:
The patent introduces an intermediary estimation process that uses inductance changes as a proxy for cookware temperature. By measuring inductance variations caused by cookware heating, the system derives temperature information indirectly, which then complements direct temperature sensor readings to achieve more accurate overall estimation
2Speed
If electrical estimation based on inductance is used alone, then the response speed is improved, but the measurement accuracy deteriorates under varying cookware conditions
Solution Approach 1:
The system implements feedback by continuously monitoring both inductance changes and temperature sensor readings, then using this combined information to adjust and refine the temperature estimation. The controller processes both electrical and thermal feedback signals to maintain accurate temperature tracking across different cookware materials and heating conditions
Solution Approach 2:
The patent creates a composite estimation approach that merges electrical measurement data (inductance) with thermal measurement data (temperature sensor readings). This composite method leverages the fast response of electrical sensing while compensating for its accuracy limitations under varying conditions using thermal sensing data
3Measurement precision
If thermal estimation based on temperature sensor is used alone, then the measurement accuracy is improved, but the response speed deteriorates due to thermal lag
Solution Approach 1:
The system performs preliminary temperature estimation using inductance measurements before the temperature sensor fully responds. By deriving an initial temperature estimate from electrical parameters, the system can react immediately to heating changes, then refine this estimate as thermal sensor data becomes available, effectively anticipating temperature changes before thermal lag prevents detection
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 rapid and accurate temperature estimation, improving cooking performance by quickly adapting to changes and maintaining precision, thus enhancing the cooking experience.
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
AI summary
An induction cooking appliance includes a cooktop having a cook surface, an induction coil below the cook surface and configured to heat cookware on the cook surface, a temperature sensor coupled to the cooktop and configured to provide a temperature signal indicative of a temperature of the cook surface, and control circuitry in communication with the induction coil and the temperature sensor. The control circuitry is configured to measure an inductance of the induction coil, determine a first temperature estimate based on the inductance, determine a second temperature estimate based on the temperature signal, estimate a temperature of the cookware based on the first temperature estimate and the second temperature estimate, compare the estimated temperature of the cookware to a target temperature set by a user, and control power supplied to the induction coil based on the comparison.