Induction Hob Temperature Control Without Absolute Sensors
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Solution Overview
Problem
Existing methods for operating induction hobs lack efficient control over cooking vessel temperature without absolute temperature measurement, relying on indirect methods and struggling to maintain constant temperatures, especially around 200°C, for frying processes.
Innovation Solution
A method that uses a control system to adjust the heating output of the induction heating coil based on a predetermined target temperature, employing a high initial heating output followed by a significantly lower output for stabilization, with periodic checks to adjust the heating power and maintain the target temperature without explicit temperature sensors, utilizing the relationship between heating power and cooking vessel temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If no temperature measuring devices are used to detect absolute cooking vessel temperature, then device complexity is reduced, but temperature control precision deteriorates
Solution Approach 1:
The patent uses an intermediary substance (water) and its phase change properties as a mediator to indirectly determine cooking vessel temperature. Instead of directly measuring the pan temperature, the system measures the temperature of water in the pan, which serves as an intermediary indicator of the cooking surface temperature through thermal conduction.
Solution Approach 2:
The patent replaces complex mechanical temperature measurement systems with a simplified system based on electrical heating control and phase change observation. The mechanical/physical temperature sensing devices are substituted by an electrical system that controls heating power and observes cooking outcomes (phase changes, temperature-dependent properties) to infer temperature.
2Speed
If high initial heating output is used to quickly reach target temperature, then heating speed is improved, but energy consumption increases
Solution Approach 1:
The patent applies dynamic control of heating power, adjusting the heating output based on the real-time temperature state and distance to target temperature. The system transitions from high power when far from target to low power when approaching target, optimizing both heating speed and energy efficiency through continuous adaptation.
Solution Approach 2:
The patent employs periodic measurement and adjustment cycles, where the system periodically checks temperature (or temperature-dependent properties) and adjusts heating power accordingly. This periodic feedback control allows the system to use high power when needed and low power when the target is approached, balancing speed and energy consumption.
3Stability of the object's composition
If heating power is continuously adjusted to maintain constant temperature, then temperature stability is improved, but control complexity increases
Solution Approach 1:
The patent implements feedback control by continuously monitoring temperature (or temperature-dependent properties) and adjusting heating power based on the difference between actual and target temperature. This feedback mechanism maintains temperature stability while using a relatively simple control algorithm that compares current state with desired state and adjusts accordingly.
Solution Approach 2:
The patent maintains temperature stability by changing the heating power parameter in response to temperature variations. Instead of complex multi-parameter control, the system focuses on adjusting the single critical parameter of heating power based on temperature feedback, simplifying the control system while achieving stable temperature maintenance.
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
Effectively sets and maintains specific cooking vessel temperatures between 150°C and 250°C, particularly 200°C, ensuring consistent frying conditions without the need for absolute temperature measurement, allowing for precise control and efficient energy use.
Implementation Method 1
inductively heating it by the induction heating coil
Implementation Method 2
inductively heating it by the induction heating coil
Implementation Method 3
The cooking vessel temperature is determined only indirectly via other properties of the cooking vessel, such as temperature-dependent permeability changes
Data Source
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Figure 5~6
AI summary
In a method for operating an induction hob with a controller and with a hotplate with an induction heating coil, a relationship between a cooking vessel temperature and a heating output of the induction heating coil is stored as a surface power in the controller, which causes a constant cooking vessel temperature during continuous operation. By monitoring whether the cooking vessel temperature remains constant, rises or falls after a heating-up time with high heat output when setting a first relatively low heat output, a target temperature that corresponds to the first relatively small heat output can be set for frying processes.