Grounded Insulation Housing for Compact Isolation Transformers

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Solution Overview

Problem

Existing solid state transformers face challenges in reducing volume and improving power density due to insulation material waste and insufficient space utilization, which is exacerbated by high working frequencies and small volumes, leading to reduced applicability and increased costs.

Innovation Solution

The isolation transformer employs a solid insulation housing that covers high-voltage and low-voltage windings, with conducting or semi-conducting layers grounded to implement solid insulation processing, reducing the need for additional insulation material and space, thereby optimizing internal space usage and enhancing power density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solid insulation material filling processing is performed on the entire winding, then insulation requirements are met, but insulation materials and space are wasted

Engineering Contradiction:
Improveinsulation requirementVSAvoidtransformer volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent applies different insulation treatments to different parts of the winding structure. Specifically, only the high-voltage winding receives solid insulation material filling processing, while the low-voltage winding uses a different approach (coating with semi-conductive material and grounding). This localized differentiation meets insulation requirements for high-voltage sections while avoiding unnecessary material usage and space occupation in low-voltage sections.

Inventive Principle:
Principle #3Local quality

2Reliability

If solid insulation material filling processing is performed on the entire winding, then insulation requirements are met, but heat dissipation during air cooling becomes difficult

Engineering Contradiction:
Improveinsulation requirementVSAvoidheat dissipation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent implements localized insulation processing where only the high-voltage winding is filled with solid insulation material, while the low-voltage winding is coated with semi-conductive material and grounded. This selective approach ensures insulation requirements are met for high-voltage sections while maintaining heat dissipation capability in low-voltage sections through air cooling, as the semi-conductive coating provides sufficient insulation without blocking heat transfer paths.

Inventive Principle:
Principle #3Local quality

3Reliability

If extra space is reserved between high-voltage side circuit and low-voltage side circuit to meet electric clearance requirement, then insulation requirements are met, but internal space of converter cannot be effectively used

Engineering Contradiction:
Improveelectric clearance requirementVSAvoidpower density
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies differentiated insulation strategies to high-voltage and low-voltage windings. The high-voltage winding receives solid insulation material filling that provides enhanced electric clearance within the winding structure itself, while the low-voltage winding uses semi-conductive material coating with grounding. This allows reduced spacing between high-voltage and low-voltage circuits while maintaining required electric clearance, thereby improving power density and space utilization.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces a semi-conductive material layer as an intermediary between the low-voltage winding and surrounding structures. This semi-conductive coating, when grounded, provides an intermediate potential layer that enhances electric clearance without requiring additional physical spacing, effectively acting as a mediator that allows closer packing of components while meeting insulation requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach effectively reduces the volume of the isolation transformer, saves insulation material, and improves power density by minimizing air gaps between conversion modules, ensuring lower costs and higher applicability.

Implementation Method 1

a solid insulation layer, a conducting layer or a semi-conducting layer is disposed on the solid insulation layer, and the conducting layer or the semi-conducting layer is grounded, to implement solid insulation processing on the high-voltage winding

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Data Source

PatentEP4283641B1Isolation transformer and power converter
Publication Date: 2025.08.27 HUAWEI TECH CO LTD
  • EP4283641B1 patent drawingFigure 1
  • EP4283641B1 patent drawingFigure 2
  • EP4283641B1 patent drawingFigure 3

AI summary

This application provides an isolation transformer. The isolation transformer is applicable to a power converter, the power converter further includes a first power conversion module and a second power conversion module, the isolation transformer includes a high-voltage winding, a low-voltage winding, and a solid insulation housing, the high-voltage winding is connected to the first power conversion module, and the low-voltage winding is connected to the second power conversion module. The high-voltage winding has a solid insulation layer, a conducting layer or a semi-conducting layer is disposed on the solid insulation layer, and the conducting layer or the semi-conducting layer is grounded. The solid insulation housing has an opening surface, the opening surface faces the second power conversion module, the solid insulation housing covers the low-voltage winding and the high-voltage winding that has the solid insulation layer, a conducting layer or a semi-conducting layer is disposed on the solid insulation housing, and the conducting layer or the semi-conducting layer of the solid insulation housing is grounded. In this application, a volume of the isolation transformer can be reduced, power density of the power converter can be improved, and low costs and high applicability can be ensured.