Integrated Transformer-LCL Filter for Compact Power Converters
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Solution Overview
Problem
Existing electric power converters for MVAC/LVAC to LVDC conversion require significant space, complexity, and higher material usage due to discrete components, leading to increased size and cost.
Innovation Solution
The transformer and LCL-filter are partially magnetically combined, sharing magnetic components to reduce the overall size and complexity by integrating filter parts into the transformer, utilizing stray inductance for the grid side choke and potentially splitting components on both sides of the transformer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If discrete components are used for transformer and LCL-filter, then the converter can be assembled and maintained separately, but the total system size and complexity increase
Solution Approach 1:
The patent combines the transformer and LCL-filter into a single integrated unit where the filter inductors are magnetically coupled to the transformer core. This merging eliminates separate discrete components for the transformer and filter, reducing the total number of components and interfaces while maintaining manufacturability through standardized integrated assemblies.
Solution Approach 2:
The integrated transformer-LCL-filter unit performs multiple functions simultaneously: voltage transformation through the transformer and current filtering through the LCL-filter. The magnetic coupling structure enables both functions within a single component assembly, reducing system complexity without sacrificing modular assembly capabilities.
2Manufacturing precision
If discrete components are used for transformer and LCL-filter, then each component can be optimized independently, but the overall system size increases
Solution Approach 1:
The LCL-filter inductors are nested within the transformer structure by magnetically coupling them to the transformer core. The filter inductors share the transformer's magnetic path and physical space, allowing both components to occupy overlapping volumes. This nesting arrangement enables independent optimization of each component's performance while significantly reducing the overall system footprint compared to discrete side-by-side arrangements.
3Adaptability or versatility
If more interfaces are provided between discrete components, then system modularity is improved, but system complexity and cost increase
Solution Approach 1:
By merging the transformer and LCL-filter into a single integrated unit, the patent eliminates multiple interfaces between separate components. The electrical and magnetic connections that would exist between discrete transformer and filter components are internalized within the integrated unit, reducing the number of external interfaces and associated complexity while maintaining system adaptability through standardized integration.
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 integration results in a smaller, less complex, and more efficient power converter with reduced material requirements, lower costs, and simpler interfaces while maintaining robustness.
Implementation Method 1
the transformer and the LCL-filter are at least partially magnetically combined with each other. In particular, inductive components of the LCL-filter are at least partially magnetically combined with the transformer
Implementation Method 2
By using the stray inductance of the transformer, it is possible to move some of the filter parts to the MV side or primary side of the transformer
Data Source
AI summary
An electric power converter, in particular for MVAC/LVAC to LVDC electric power conversion drives, including an active front end AFE, a transformer and an LCL-filter with a grid side choke and a drive side choke. According to the disclosure, the transformer and the LCL-filter are at least partially magnetically combined with each other.