Interleaved LLC Power Converter Resonance Matching
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Solution Overview
Problem
Interleaved LLC power converters face significant challenges due to high output ripple current, which prevents their use in many power system topologies, especially when multiple converters are coupled to a common load, primarily caused by mismatched resonant frequencies and inductance of resonant inductors.
Innovation Solution
The implementation of substantially matched resonant inductors and capacitors in interleaved LLC power converters, with a method to adjust these components to match resonance frequencies, allowing for better matching of resonant frequencies and reducing inductive variation, thereby minimizing output ripple current and enabling effective interleaving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LLC power converters are interleaved to increase output current capability, then productivity is improved, but output ripple current increases making the system unusable
Solution Approach 1:
The patent applies parameter changes by precisely adjusting the resonant frequency of each LLC converter through component selection (inductors and capacitors) to ensure all converters operate at the same resonant frequency. This frequency parameter matching transforms the interleaved operation from harmful (high ripple) to beneficial (low ripple), enabling high output current capability while maintaining low output ripple current.
2Device complexity
If resonant inductors with different inductance values are used in interleaved LLC converters, then device complexity is reduced, but manufacturing precision is worsened due to resonance mismatch
Solution Approach 1:
The patent resolves this contradiction by changing the approach from using identical inductors to using inductors with different inductance values while compensating through capacitor selection. Each converter's total resonant frequency (determined by L and C values) is adjusted to match, allowing component variation while maintaining precision resonance frequency matching.
3Manufacturing precision
If resonant capacitors are adjusted to match resonance frequencies, then manufacturing precision is improved, but device complexity increases due to additional component matching requirements
Solution Approach 1:
The patent applies parameter changes by using resonant capacitors with different capacitance values to compensate for inductor variations. This allows each converter to be tuned to the same resonant frequency despite component differences, improving manufacturing precision while the complexity is managed through systematic component selection rather than additional matching processes.
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 reduces the variation in output current ripple, allowing for higher overall output current through a common load and supports effective interleaving of LLC power converters, leading to improved performance and reduced electromagnetic emissions.
Implementation Method 1
a first resonant inductor, a first magnetic inductor, and a first resonant capacitor coupled to the first LLC voltage source
Implementation Method 2
a first magnetic inductor and a first resonant capacitor coupled to the first LLC voltage source
Data Source
AI summary
A system is provided having a first LLC power converter and a second LLC power converter. The first LLC power converter comprises a first LLC voltage source. The second LLC power converter also comprises a second LLC voltage source. The first LLC power converter also comprises a first resonant inductor, a first magnetic inductor, and a first resonant capacitor coupled to the first voltage source of the first LLC power converter. The second LLC power converter comprises a second resonant inductor, a second magnetic inductor, and a second resonant capacitor coupled to the second voltage source of the second LLC power converter. The first LLC power converter and the second LLC power converter are both magnetically couplable to a common load. A resonance of the first LLC power converter substantially matches a resonance of the second LLC power converter.