Induction Heating Element Temperature via Resonant Circuit Resistance
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Solution Overview
Problem
Existing methods for determining the temperature of a heating element in induction heating systems require additional components or access to the heating element, limiting their applicability and increasing costs.
Innovation Solution
A device utilizing a resonant circuit with an induction coil and a heating element with constant permeability, where the temperature-dependent resistance of the heating element is calculated from the resonance frequency and power consumption of the resonant circuit, allowing for contactless temperature determination without additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors or optical temperature measuring devices are used, then temperature measurement capability is achieved, but additional components are required and installation space is increased
Solution Approach 1:
The heating element itself serves as the temperature sensor by utilizing its own temperature-dependent electrical resistance. The control unit determines temperature by measuring the electrical properties of the heating element during operation, eliminating the need for separate temperature sensors or optical measuring devices.
Solution Approach 2:
The heating element performs dual functions: it generates heat through induction and simultaneously serves as the temperature sensing element. By monitoring the electrical resistance or impedance of the heating element, the system obtains temperature information without requiring dedicated measurement components.
2Measurement precision
If optical temperature measuring devices are used, then contactless temperature determination is achieved, but the measured region must be visible and accessible
Solution Approach 1:
The heating element's own electrical properties provide temperature information without requiring external observation or access. The control unit measures electrical parameters (such as impedance or power consumption) directly from the heating element circuit, enabling temperature determination regardless of the heating element's physical accessibility or visibility.
3Measurement precision
If methods utilizing temperature-dependent permeability properties are used, then temperature determination is achieved, but material selection is limited and only special material/temperature range combinations are applicable
Solution Approach 1:
The method utilizes the temperature-dependent electrical resistance of the heating element material rather than temperature-dependent magnetic permeability. This approach works with any electrically conductive material that exhibits resistance changes with temperature, significantly broadening material compatibility compared to permeability-based methods that require specific ferromagnetic materials with characteristic Curie points.
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 simple, cost-effective temperature measurement of the heating element by correlating the temperature-dependent resistance with the inductance and resistance of the induction coil, facilitating efficient heat output regulation without the need for additional components or access.
Implementation Method 1
Electrically conductive materials can be heated by induction. This occurs by placing an electrically conductive material in a magnetic field generated by an induction coil. The magnetic field is hereby generated by an alternating current, which results in a polarity reversal of the magnetic field at the frequency of the alternating current. Eddy currents are induced in the electrically conductive material by the alternating magnetic field. These induced alternating currents work against the specific resistance of the material, as a result of which heat is produced.
Implementation Method 2
Eddy currents are induced in the electrically conductive material by the alternating magnetic field. These induced alternating currents work against the specific resistance of the material, as a result of which heat is produced.
Implementation Method 3
These induced alternating currents work against the specific resistance of the material, as a result of which heat is produced.
Implementation Method 4
The magnetic field is hereby generated by an alternating current, which results in a polarity reversal of the magnetic field at the frequency of the alternating current.
Implementation Method 5
having an induction coil connected to a resonant circuit, wherein the resonant circuit has at least one first capacitor and at least one first current source
Data Source
AI summary
A device and method is provided for inductively heating a heating element, particularly via a magnetic field generated by an induction coil, having an induction coil connected to a resonant circuit, whereby the resonant circuit has at least one first capacitor and at least one first current source, and the coil has a specific inductance and a resistance, and the material of the heating element has a constant permeability at least in temperature subranges, and a method for determining a temperature of a heating element.