Induction Heater Load Sensing for Cooking Vessel Detection
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Solution Overview
Problem
Existing electric cookers struggle to efficiently heat cooking vessels made of non-magnetic substances like ceramics or glass, as they require complex induction heating coil structures and inverter systems, and cannot differentiate between metallic and non-metallic vessels, leading to lower heating efficiency and user inconvenience in selecting between induction and electric heaters.
Innovation Solution
An apparatus and method that detects the presence and type of cooking vessel using input and resonance currents to determine whether to operate an induction heater or electric heater, allowing for automatic selection based on the vessel's material, ensuring efficient heating of both magnetic and non-magnetic substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an induction heating coil structure is designed to heat non-magnetic substances, then heating versatility is improved, but device complexity increases
Solution Approach 1:
The induction heating coil is designed with multi-functionality to serve both magnetic and non-magnetic cooking vessels. By incorporating this universal design, the same coil structure can effectively heat different types of vessels without requiring separate specialized coils, thereby improving heating versatility while managing device complexity through a single versatile component rather than multiple specialized ones
2Adaptability or versatility
If an inverter system is added to supply high frequency current, then heating capability for non-magnetic substances is improved, but device complexity and economic costs increase
Solution Approach 1:
The inverter system is designed with multi-functionality to support both induction heating modes (for magnetic vessels) and high-frequency current supply modes (for non-magnetic vessels). This universal inverter design eliminates the need for separate inverter systems for different heating modes, thereby improving heating capability while managing device complexity and economic costs through a single versatile inverter rather than multiple specialized systems
3Adaptability or versatility
If operation frequency is increased for non-magnetic vessels, then heating capability is improved, but energy consumption increases
Solution Approach 1:
The system dynamically adjusts the operation frequency of the induction heating coil based on the detected type of cooking vessel. When a non-magnetic vessel is detected, the system increases the operation frequency to optimize heating capability. When a magnetic vessel is detected, the system operates at standard frequency. This dynamic adjustment ensures optimal heating performance while managing energy consumption by applying higher frequencies only when necessary
4Productivity
If heating efficiency is optimized for magnetic vessels, then heating performance is improved, but adaptability to non-magnetic vessels deteriorates
Solution Approach 1:
The system dynamically adapts its heating parameters based on the detected vessel type. When a magnetic vessel is detected, the system optimizes for maximum heating efficiency using standard induction parameters. When a non-magnetic vessel is detected, the system dynamically adjusts to high-frequency current supply mode to maintain effective heating capability. This dynamic adaptation allows the system to achieve optimal heating efficiency for magnetic vessels while maintaining adaptability to non-magnetic vessels
5Ease of operation
If automatic vessel detection is implemented, then user convenience is improved, but device complexity increases
Solution Approach 1:
The system implements automatic vessel detection and classification without requiring user intervention. The detection circuit automatically identifies whether a magnetic or non-magnetic vessel is present and communicates this information to the control unit, which then automatically selects the appropriate heating mode. This self-service capability improves user convenience by eliminating the need for manual vessel type selection while managing device complexity through automated detection rather than complex manual interface systems
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
Enables efficient and automatic operation of either the induction or electric heater based on the cooking vessel's material, improving heating efficiency and user convenience by accurately determining the vessel's presence and type, preventing unnecessary energy consumption and potential safety hazards.
Implementation Method 1
An induction heating electric cooker supplies a high frequency electric current to an induction heating coil to generate high frequency magnetic flux. The high frequency magnetic flux is induced into a cooking vessel placed on the top of a heater unit by an induction effect to generate an eddy current in the cooking vessel.
Implementation Method 2
Joule heat is generated in a resistance portion of the cooking vessel by the generated eddy current. The cooking vessel is heated by the generated Joule heat.
Implementation Method 3
a signal with a certain frequency generated by an oscillation circuit produces frequency displacement in accordance with existence or non-existence of the cooking vessel and also generates a phase difference between voltage and current. The conductive sensor loop detects a phase difference between the voltage and current of the signal with a certain frequency
Data Source
AI summary
A heater unit is provided, the heater unit equipped with an induction heating coil and an electric heater selectively operated based on kind and state of a load of a cooking vessel placed on the heater unit. The kind is determined by an input current inputted when a load-type determination unit causes the induction heating coil to be operated and a resonance current flowing into the induction heating coil. The state is determined by a temperature change of the heater unit when a load-state determination unit allows the electric heater to generate heat, and the induction heating coil and the electric heater are selectively operated based on the determined kind and state of the load. Accordingly, a user needs not to scrupulously determine the kind of the cooking vessel and the electric cooker is not operated under a no-load state to prevent occurrence of safety accidents.