Transformer Winding Segmentation for Short-Circuit Impedance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current transformers face challenges in achieving sufficient short-circuit impedance for secondary windings, particularly when used in medium or high voltage inverters, leading to potential current overload issues.
Innovation Solution
The transformer design includes a magnetic core with a primary winding divided into sections and pull-out portions, and secondary windings arranged along the axial direction, with adjustable gaps between winding sections and windings to increase leakage flux and short-circuit impedance. This configuration allows for customization of gap sizes and numbers to achieve the required short-circuit impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the secondary windings are wound using disk winding method, then the winding structure is simplified and manufacturing is easier, but the short-circuit impedance is insufficient leading to current overload problems
Solution Approach 1:
The secondary windings are divided into multiple independent winding units arranged axially along the magnetic core. Each winding unit is separated from others by insulating structures, creating distinct magnetic circuits. This segmentation increases leakage flux between windings and thereby increases short-circuit impedance while maintaining the simplicity of disk winding manufacturing method
Solution Approach 2:
Insulating structures including insulating pillars and insulating layers are introduced between adjacent secondary windings. These intermediary elements increase the physical distance and magnetic reluctance between windings, enhancing leakage flux and short-circuit impedance without complicating the winding process itself
2Reliability
If the short-circuit impedance is increased to prevent current overload, then safety is improved, but the device complexity increases due to additional insulating structures and winding configurations
Solution Approach 1:
The secondary windings are divided into multiple independent winding units arranged axially along the magnetic core. Each winding unit is separated from others by insulating structures, creating distinct magnetic circuits. This segmentation increases leakage flux between windings and thereby increases short-circuit impedance while maintaining the simplicity of disk winding manufacturing method
Solution Approach 2:
The insulating structures serve multiple functions: they provide electrical insulation between windings, increase leakage flux for higher short-circuit impedance, and maintain mechanical spacing. This multi-functionality achieves current overload protection without proportionally increasing device complexity
3Reliability
If multiple secondary windings are arranged axially distributed along the magnetic core, then the short-circuit impedance is increased, but the space utilization and compactness are reduced
Solution Approach 1:
The secondary windings are arranged in the axial dimension along the magnetic core rather than being stacked radially or in parallel. This axial distribution along the length of the core efficiently utilizes the available space while creating the necessary leakage flux paths, achieving higher short-circuit impedance without excessive volume increase
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 effectively increases short-circuit impedance, reducing the risk of current overload and enhancing safety by managing inter-layer voltage and facilitating heat dissipation, while maintaining efficient operation and space utilization.
Implementation Method 1
The uncoupled magnetic flux between the second windings and the first winding (that is the leakage flux) can generate inductive impedance
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A transformer includes a magnetic core, a primary winding, and a plurality of secondary windings. The magnetic core has an axial and a radial direction. The primary winding includes a plurality of winding sections and at least one connecting section. The winding sections are arranged along the axial direction. The connecting section is connected between the two adjacent winding sections. Each of the winding sections includes a plurality of primary winding layers and pull-out portions. The primary winding layers surround the magnetic core and are arranged along the radial direction. One pull-out portion connects two primary winding layers adjacent to the pull-out portion. Part of normal projections of the primary winding layers on a surface of the magnetic core are located between normal projections of the pull-out portions on the surface of the magnetic core. The secondary windings surround the primary winding.