Dual Foil Inductor Assembly for Compact High-Voltage Insulation

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Solution Overview

Problem

Conventional inductor coil designs are large in size and unable to withstand significant transient overvoltages, with minimal contact between turns leading to vibration issues and increased space requirements due to insulation needs.

Innovation Solution

The design features a spirally wound metal foil with a thin, wide configuration and an insulating sheet, not bonded during winding, housed in a cylindrical enclosure with epoxy resin and heat-shrinkable insulation, providing adequate insulation and stability while minimizing size and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional inductor coil designs are used, then insulation between turns is provided, but the size is large and weight is increased due to minimal contact between turns requiring more insulation space

Engineering Contradiction:

Improveinductor sizeVSAvoidinsulation between turns

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent applies this principle by using a thin insulating film (0.002 to 0.006 inches thick) wrapped around the foil windings instead of bulky insulation structures. This thin film provides adequate electrical insulation between turns while minimizing the space required, thus reducing overall inductor size and weight while maintaining insulation reliability.

Inventive Principle:

Principle #30Flexible shells and thin films

2Stability of the object's composition

If conventional inductor coil designs are used, then coils are formed, but vibration issues occur due to minimal contact between turns

Engineering Contradiction:

Improvecoil stabilityVSAvoidvibration

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent applies this principle by combining the insulation function with the structural stabilization function. The insulating film not only provides electrical insulation but also acts as a binding agent that holds adjacent windings in close contact, eliminating vibration issues. This merging of functions allows the coil to maintain stability without requiring separate vibration damping structures.

Inventive Principle:

Principle #5Merging (Combining)

3Volume of moving object

If箔 width is increased to reduce inductor size, then compactness is achieved, but flashover risk increases under transient overvoltages

Engineering Contradiction:

Improveinductor sizeVSAvoidflashover risk

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies this principle by using a composite structure consisting of the metal foil winding combined with a specialized insulating film. This composite material system provides both the compact geometry needed for small size and the high dielectric strength required to withstand transient overvoltages without flashover. The insulating film is specifically selected to have properties that prevent electrical breakdown even when the foil width is increased for compactness.

Inventive Principle:

Principle #40Composite materials

4Reliability

If insulation thickness is increased to prevent flashover, then safety is improved, but device complexity and space requirements increase

Engineering Contradiction:

Improveflashover preventionVSAvoidinsulation structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies this principle by replacing complex multi-layer insulation structures with a single thin insulating film (0.002 to 0.006 inches thick) that provides adequate flashover protection. This thin film is applied directly to the foil windings and provides the necessary dielectric strength without requiring bulky insulation structures, thus maintaining reliability while reducing device complexity and space requirements.

Inventive Principle:

Principle #30Flexible shells and thin films

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 solution effectively reduces the risk of flashover, enhances insulation between turns, and maintains stability under transient conditions, while being compact and lightweight, suitable for high-voltage applications.

Implementation Method 1

an electrically insulating epoxy resin surrounding and engaging the coil

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

an electrically insulating heat shrunk tube surrounding a portion of the terminal bus bar

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS11798731B2Inductor assemblies and methods for forming the same

Publication Date: 2023.10.24 RAYCAP SA

AI summary

A dual coil inductor assembly includes an inner coil assembly including an inner coil and first and second terminals, and an outer coil assembly including an outer coil and third and fourth terminals. The inner coil includes an inner metal foil, and an inner electrical insulator sheet spirally co-wound with the inner metal foil. The outer coil includes an outer metal foil, and an outer electrical insulator sheet spirally co-wound with the outer metal foil. The inner coil is disposed within an outer coil air core of the outer coil so that the outer coil circumferentially surrounds the inner coil. The first and second terminals are electrically connected to the inner metal foil at respective first and second locations spaced apart along the inner metal foil. The third and fourth terminals are electrically connected to the outer metal foil at respective third and fourth locations spaced apart along the outer metal foil.