Stepped Ferrite Core for Induction Heating Flux Efficiency
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Solution Overview
Problem
Induction heating devices with zone-free type induction heating face challenges in using high-output working coils due to size constraints and the need for creepage distance to prevent electric shock, which limits the placement of resonance capacitors and reduces magnetic flux efficiency.
Innovation Solution
The induction heating device incorporates a ferrite core with stepped corners, a base plate with corresponding connection holes, and an indicator substrate with connectors that prevent contact between the ferrite core and working coil terminals, allowing for a high-output working coil configuration while maintaining safety through increased creepage distance and efficient magnetic flux direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high-output working coil is used, then heating performance is improved, but the device size increases and space for resonance capacitors is reduced
Solution Approach 1:
The patent utilizes the vertical dimension by positioning resonance capacitors below the working coil assembly, rather than only in horizontal space. This allows high-output coils to be used without compromising the horizontal area available for other components.
Solution Approach 2:
The patent integrates resonance capacitors into the vertical stack beneath the working coil and ferrite core assembly, nesting multiple functional components in a compact vertical arrangement that maximizes space utilization.
2Reliability
If creepage distance is increased to prevent electric shock, then safety is improved, but the placement flexibility of resonance capacitors is reduced
Solution Approach 1:
The patent resolves the creepage distance constraint by moving resonance capacitors to the vertical dimension below the working coil, where sufficient horizontal separation distance can be maintained while still providing safe electrical isolation.
Solution Approach 2:
The patent introduces insulating structures and spacing elements as intermediaries between high-voltage components, ensuring adequate creepage distance is maintained while still allowing flexible placement of resonance capacitors in available spaces.
3Loss of energy
If ferrite core size is increased to reduce magnetic flux leakage, then heating efficiency is improved, but the available space for terminals and connections is reduced
Solution Approach 1:
The patent segments the ferrite core into multiple sections with stepped configurations, allowing terminals and connections to be positioned in gaps and spaces between segments, thus maintaining large overall core size for flux efficiency while providing access points for electrical connections.
Solution Approach 2:
The patent positions terminals and connection points in the vertical dimension and at angular offsets around the ferrite core, utilizing three-dimensional space rather than only horizontal plane, thereby accommodating both large core size and connection requirements.
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 configuration enables the use of high-output working coils, improving performance and reliability by enhancing magnetic flux efficiency and preventing electric shock accidents, thus increasing user safety and device effectiveness.
Implementation Method 1
a ferrite core disposed vertically below the working coil and configured to direct upward an alternating magnetic field generated by the working coil
Implementation Method 2
In the induction heating method, eddy current may be generated in the object made of metal based on a magnetic field generated around the coil based on a high-frequency power having a predetermined magnitude applied to the coil to heat the object
Implementation Method 3
a working coil including a conducting wire that is wound in an annular shape and that is connected to a plurality of electric terminals
Data Source
AI summary
An induction heating device includes: a working coil including a conducting wire that is wound in an annular shape and that is connected to a plurality of electric terminals; a ferrite core disposed vertically below the working coil and configured to direct upward an alternating magnetic field generated by the working coil, the ferrite core defining a stepped portion at each corner of the ferrite core; a base plate that supports the ferrite core on an upper surface of the base plate and that defines a connection hole having a shape corresponding to the corner of the ferrite core; and an indicator substrate disposed vertically below the base plate. The indicator substrate includes a connector that is disposed on an upper surface of the indicator substrate, that is coupled to one or more of the plurality of electric terminals, and that protrudes upward through the connection hole.