Multi-coil Induction Hob with Controllable Magnetic Fluid
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Solution Overview
Problem
Induction hobs with multiple coils are costly due to the need for complex multiple-output inverters to control electromagnetic field distribution, which increases with the number of coils, making precise and efficient heating less economical.
Innovation Solution
A multi-coil induction hob using a controllable magnetic fluid to guide and tune the electromagnetic field, allowing for precise control of electromagnetic field distribution and reducing the complexity of the inverter system by acting as a tunable inductance at each load coil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple induction coils are used to enable flexible cooking anywhere on the hob surface, then heating flexibility and EM field control are improved, but the complexity and cost of the multiple-output inverter system increases
Solution Approach 1:
A magnetic fluid intermediary is introduced between the induction coils and the cookware. This magnetic fluid acts as a mediator that can be dynamically controlled to shape and direct the electromagnetic field, enabling flexible heating patterns without requiring complex multi-output inverter control for each coil. The magnetic fluid absorbs and redirects EM energy, providing adaptability through a simpler control mechanism.
Solution Approach 2:
The system changes the physical state and distribution parameters of the magnetic fluid to control EM field behavior. By adjusting the magnetic fluid's position, concentration, and distribution across the hob surface, the system achieves versatile heating patterns. This parameter-based control is simpler than controlling multiple independent coil outputs, resolving the contradiction between flexibility and complexity.
2Manufacturing precision
If more coils are used to improve EM field distribution control, then heating precision and evenness are improved, but component count and manufacturing cost increase
Solution Approach 1:
The magnetic fluid serves as an intermediary that simplifies the coil configuration. Instead of using many small coils to achieve precise EM field distribution, the system uses fewer coils combined with magnetically controllable fluid. The magnetic fluid can be precisely positioned and shaped using magnetic fields, achieving heating precision without the need for numerous expensive coil components.
Solution Approach 2:
The system replaces a mechanical/proliferating coil structure with a magnetic field-controlled fluid system. Rather than adding more physical coils to improve precision, the invention uses magnetic fields to control the magnetic fluid's distribution and shape, thereby achieving precise heating control through a less complex, more manufacturable system.
3Adaptability or versatility
If a multiple-output inverter is used to control current flow to each coil, then area cooking functionality is achieved, but component cost scales poorly with higher number of coils
Solution Approach 1:
The magnetic fluid provides multi-functionality that replaces the need for complex multi-output inverter control. A single or reduced number of inverters can control the magnetic fluid's overall behavior, and the magnetic fluid itself adapts to provide various heating patterns and area cooking functionalities. This universal approach achieves area cooking without costs scaling with the number of coils.
Solution Approach 2:
The magnetic fluid acts as an intermediary layer that decouples the simplicity of single-output or reduced-output inverter control from the complexity of achieving area cooking functionality. The magnetic fluid can be manipulated to create different heating zones and patterns, providing area cooking capabilities while keeping the inverter system simple and cost-effective.
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 solution enables efficient, flexible, and safe heating of cookware anywhere on the hob surface with reduced component costs and improved power coupling, providing more precise control over electromagnetic fields and even heating.
Implementation Method 1
During IH an alternating current source driving a coil generates alternating electromagnetic fields. These electromagnetic fields penetrate inside a conducting and/or permeable target (object to be heated), and induce eddy currents and magnetic dipoles within it.
Implementation Method 2
Inside the target, eddy currents which oppose the alternating magnetic field applied to the induction target produce heating by the Joule effect.
Implementation Method 3
In addition to this, magnetic hysteresis creates additional heating in ferromagnetic materials.
Implementation Method 4
the hob provides increased control over electromagnetic (EM) field spatial distribution in the vicinity of the hob by guiding the EM field through the controllable magnetic fluid, and allows for more precise tuning of each load (which varies with cookware geometry, material properties, and placement) by controlling the volume and spatial distribution of magnetic fluid at each load coil, effectively acting as a tunable inductance in each load.
Data Source
AI summary
An induction hob uses induction heating to provide safe, energy efficient and flexible heating of vessels by using multiple coils and a controllable magnetic fluid. In addition, the hob provides increased control over electromagnetic (EM) field spatial distribution in the vicinity of the hob by guiding the EM field through the controllable magnetic fluid, and allows for more precise tuning of each load (which varies with vessel geometry, material properties, and placement) by controlling the volume and spatial distribution of magnetic fluid at each load coil, effectively acting as a tunable inductance in each load.