PCB Planar Winding Structure for Power Transformer

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Solution Overview

Problem

Existing medium voltage transformer designs face challenges such as partial discharge, complexity in manufacturing, and inefficiency due to the need for reliable insulation and thermal management, particularly in high-frequency applications where traditional solutions like litz wire and coaxial structures are cumbersome and difficult to scale.

Innovation Solution

A planar winding structure using a printed circuit board (PCB) with embedded conductive layers, shielding layers, and a grading ring structure to control electrical stress and reduce partial discharge, integrated with a magnetic core for efficient power transformation, allowing for modular and easy manufacturing while maintaining high efficiency and thermal performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If litz wire is used for windings with epoxy-based insulation, then insulation breakdown strength is improved, but manufacturing complexity increases and insulation quality control becomes difficult due to high viscosity and unavoidable voids

Engineering Contradiction:
Improveinsulation breakdown strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent changes the viscosity parameter of the insulation material by using low-viscosity silicone rubber compound instead of high-viscosity epoxy resin, enabling complete infiltration into litz wire gaps and eliminating voids while simplifying the manufacturing process to a single-step injection molding operation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite insulation system combining silicone rubber compound with specific fillers and curing agents to achieve both low viscosity for complete infiltration and high breakdown strength for reliable insulation, resolving the contradiction between ease of manufacture and insulation strength

Inventive Principle:
Principle #40Composite materials

2Reliability

If two-layer insulation system with mold is used, then insulation quality is improved, but device complexity and manufacturing difficulty increase due to multiple steps and customized molds

Engineering Contradiction:
Improveinsulation qualityVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of multiple insulation layers and the curing process into a single injection molding operation using low-viscosity silicone rubber compound that can simultaneously fill all gaps and cure uniformly, eliminating the need for separate molds and multiple processing steps while maintaining high insulation quality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single-step injection molding process serves multiple functions simultaneously: it provides the insulation layer, fills all voids between litz wire strands, provides mechanical support, and creates a sealed structure, replacing the need for multiple specialized molds and processes

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Area of stationary object

If high frequency operation is used, then transformer footprint is reduced, but insulation reliability becomes more critical and difficult to maintain

Engineering Contradiction:
Improvetransformer footprintVSAvoidinsulation reliability
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent changes the material parameters by selecting silicone rubber compound with specific dielectric properties and low viscosity, enabling the insulation to withstand high-frequency electric stress while maintaining complete infiltration into windings and eliminating partial discharge sites that would compromise reliability at high frequencies

Inventive Principle:
Principle #35Parameter changes

4Strength

If epoxy-based insulation is used, then breakdown strength is improved, but thermal management becomes difficult due to poor thermal conductivity

Engineering Contradiction:
Improvebreakdown strengthVSAvoidthermal management
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent develops a composite silicone rubber insulation material that combines electrical insulation properties with improved thermal conductivity through specific filler selection and formulation, achieving both high breakdown strength and effective heat dissipation simultaneously

Inventive Principle:
Principle #40Composite materials

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 PCB-based planar winding structure effectively mitigates partial discharge and enhances thermal management, achieving higher efficiency and power density while simplifying manufacturing, making it suitable for medium voltage applications with reduced size and weight.

Implementation Method 1

A planar winding structure for use in a power transformer... integrated with a magnetic core for efficient power transformation

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a shielding layer... to control electrical stress and reduce partial discharge

Methodology Applied
Scientific EffectElectric field confinement: Electric Field

Implementation Method 3

The plurality of conductive layers is embedded in the winding portion of the insulating planar board and electrically connected with each other

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4160631A1Planar winding structure for power transformer
Publication Date: 2023.04.05 DELTA ELECTRONICS INC(CN)
  • EP4160631A1 patent drawingFigure 1~2
  • EP4160631A1 patent drawingFigure 3~4
  • EP4160631A1 patent drawingFigure 5

AI summary

The present disclosure provides a printed circuit board (PCB) based planar winding structure (500) for a main power transformer and/or an auxiliary power need. The PCB-based planar winding structure (500) can confine electric field through magnetic core potential control and thus create partial discharge (PD) free design for medium voltage (MV) applications. Meanwhile, the winding structure can be formed in the PCB manufacturing process to create a more modular and reliable structure, thereby enhancing manufacturability. Techniques, such as termination treatment, primary and secondary winding arrangements, etc., can be used to control the electrical stress in the medium voltage applications.