Toroidal Inductor with SMC Core and Insulated Winding
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Solution Overview
Problem
Conventional inductors face issues with energy losses, heating, harmonic distortions, and design limitations due to magnetic leak flow, fringing losses, and material inefficiencies, particularly when handling fundamental frequencies and high frequencies in power electronics applications.
Innovation Solution
A toroidal coil with a high thermal heat conduction and a soft magnetic composite core, where the coil is wound with insulated strands and coated with resin to minimize voids and enhance thermal conductivity, and the core is magnetically aligned with the H-field to optimize magnetic field distribution and reduce losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional wire winding methods are used with air gaps in the core, then the inductor can be manufactured with standardized components, but magnetic leak flow and fringing losses increase causing energy losses and heating
Solution Approach 1:
The patent changes the physical parameters of the core material by using SMC (Soft Magnetic Composite) instead of conventional iron or ferrite materials. This material substitution eliminates the need for air gaps while maintaining manufacturability, thereby reducing magnetic leak flow and fringing losses without sacrificing ease of manufacture.
Solution Approach 2:
The patent employs SMC, a composite material consisting of soft magnetic metallic particles mixed with binder and filler materials. This composite structure allows the core to be formed without air gaps while maintaining magnetic properties, thus resolving the contradiction between standardized manufacturing and energy loss reduction.
2Reliability
If the coil is wound over air gaps to control permeability, then core saturation is prevented, but considerable fringing losses occur creating hot-spots that are difficult to cool
Solution Approach 1:
The patent changes the permeability control mechanism by eliminating air gaps through the use of SMC material. The composite material's inherent properties allow permeability control without gap introduction, preventing both saturation and the associated fringing losses that create hot-spots.
Solution Approach 2:
The patent converts the potential harm of high permeability (which could lead to saturation) into a benefit by using SMC material that provides controlled permeability without air gaps. This eliminates the fringing losses and hot-spot formation while maintaining reliable saturation prevention.
3Ease of manufacture
If standardized coil formers and core materials are used, then manufacturing is simplified, but design freedom is limited resulting in ineffective and un-optimized inductor designs
Solution Approach 1:
The patent uses SMC composite material that can be molded into custom core shapes while maintaining standardized manufacturing processes. This provides both the ease of manufacture associated with standardized materials and the design freedom needed for optimized inductor geometries tailored to specific applications.
Solution Approach 2:
The patent enables design optimization by changing from standardized rigid materials to SMC composite that can be formed into various configurations. This allows customization of core geometry, winding patterns, and overall inductor design while maintaining manufacturing efficiency through the molded construction process.
4Ease of manufacture
If conventional inductor designs are used, then manufacturing costs are controlled through standardization, but energy losses and heat generation increase reducing efficiency
Solution Approach 1:
The patent employs SMC composite material that enables molded core construction, eliminating the need for traditional winding over air gaps. This reduces energy losses and heat generation while maintaining cost-effective manufacturing through the molded construction process and elimination of assembly steps.
Solution Approach 2:
The patent changes the manufacturing approach by using molded SMC construction instead of conventional winding methods. This parameter change eliminates air gaps and associated losses while maintaining manufacturing efficiency, thereby reducing both energy losses and production costs simultaneously.
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
The design results in a compact, efficient inductor with reduced energy losses, lower operating temperature, and improved performance by minimizing voids and optimizing magnetic field distribution, leading to smaller, lighter, and more cost-effective units with enhanced heat dissipation.
Implementation Method 1
the wire has an electrically insulating layer insulating each turn of the wire in the winding from neighbouring turns
Implementation Method 2
the coil has a bulk thermal heat conduction of above 0.8 W/m*K
Implementation Method 3
The thermal heat conduction and shape is achieved by compression means which reduces substantially air or gas voids present in the coil
Implementation Method 4
the core is magnetically aligned with the H-field to optimize magnetic field distribution
Implementation Method 5
A toroidal coil with a high thermal heat conduction and a soft magnetic composite core, where the coil is wound with insulated strands
Data Source
AI summary
The present invention relates to a coil (1) for an inductor (6), comprised by metal wire (2) wound circular around a centre axis (C), wherein the wire has an electrically insulating layer (3) insulating each turn of the wire in the winding from neighbouring turns, the shape of the complete winding, building up the coil (1), is substantially toroidal having a substantially elliptic cross section, wherein the thermal heat conductivity is above 1 W/m*K more preferably above 1.2 and most preferably above 1.5. The invention further relates to a magnetic core (7) suitable for an inductor (6), where in the core is made of a soft magnetic composite material made of metallic particles and a binder material, said particles are in the range of 1 μm-1000 μm, particles that are larger than 150 μm are coated with a ceramic surface to provide particle to particle electrical insulation, wherein the volume of magnetic, metallic particles to total core volume is 0.5-0.9. The invention still further relates to an inductor (6) being a combination of said coil (1) and core (7), wherein the substantially all of said particles in the core are magnetically aligned with the magnetic field of the coil. The invention still further relates to the manufacturing methods of such a coil (1) and core (7).