Interleaved LLC Converters with Integrated Magnetics
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Solution Overview
Problem
Existing power converters, such as LLC converters, face challenges with large input and output ripple currents, which can be mitigated by implementing three-phase interleaved LLC and CLLC resonant converters with integrated magnetics and specific interleaving structures to achieve current sharing and reduced ripple currents.
Innovation Solution
The solution involves integrating the transformers of the three phases into one magnetic core, using a half-bridge configuration on the primary side with delta-connected or common Y-node coupling, and a full-bridge configuration on the secondary side, allowing for interleaving of primary and secondary windings to share currents and minimize ripple currents through resonant inductors formed from leakage and magnetization inductances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If three-phase interleaved LLC and CLLC resonant converters with integrated magnetics are implemented, then input and output ripple currents are reduced, but device complexity increases
Solution Approach 1:
The patent integrates multiple functions into a single magnetic core component. The transformer and resonant inductors for three-phase interleaved LLC and CLLC converters are combined into one integrated magnetic component, reducing the number of separate components while achieving ripple current reduction through the interleaved phase structure.
Solution Approach 2:
The magnetic core is divided into multiple legs (typically three legs for three-phase operation), with each leg handling a specific phase. This segmentation allows independent optimization of each phase while maintaining the overall interleaved structure that reduces ripple currents through phase cancellation.
2Reliability
If transformers of three phases are integrated into one magnetic core, then current sharing is achieved and ripple currents are reduced, but manufacturing complexity increases
Solution Approach 1:
The integrated magnetic core serves multiple functions simultaneously: it acts as the transformer core for power transfer and as the inductor core for resonant operation in all three phases. This multi-functionality enables current sharing and ripple reduction while consolidating what would otherwise require multiple separate components.
Solution Approach 2:
Different sections of the magnetic core are optimized for different functions. Specific leg configurations, winding arrangements, and magnetic path designs are tailored to achieve proper current sharing ratios and resonant characteristics for each phase while maintaining overall integration.
3Productivity
If interleaving structure is implemented with delta-connected or common Y-node coupling, then power conversion efficiency is optimized, but device complexity increases
Solution Approach 1:
The interleaved converter structure operates with periodic switching patterns across the three phases, with each phase shifted by one-third of the switching period. This periodic action with phase displacement optimizes power conversion efficiency through continuous current flow and reduced ripple, while the integrated magnetic core provides the physical structure for this periodic operation.
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 configuration effectively reduces input and output ripple currents, achieving efficient power conversion by enabling current sharing and optimizing the input-to-output ratio, while also minimizing AC current loops and leveraging leakage inductances for resonant tank circuits.
Implementation Method 1
The first and second primary windings are wound around the first core leg, and the first and second secondary windings are wound around the second core leg
Implementation Method 2
minimize ripple currents through resonant inductors formed from leakage and magnetization inductances
Data Source
AI summary
Three-phase interleaved LLC and CLLC resonant converters, with integrated magnetics, are described. In various examples, the primary sides of the phases in the converters rely upon a half-bridge configuration and include resonant networks coupled to each other in delta-connected or common Y-node configurations. The secondary sides of the phases can rely upon a full-bridge configurations and are coupled in parallel. In one example, the transformers of the phases in the converters are integrated into one magnetic core. By changing the interleaving structure between the primary and secondary windings in the transformers, resonant inductors of the phases can also be integrated into the same magnetic core. A multi-layer PCB can be used as the windings for the integrated magnetics.