Full-Bridge Resonant Circuit Phase Coherence
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Solution Overview
Problem
Conventional full-bridge resonant conversion circuits using double transformers often produce phase differences and high-frequency oscillations at secondary sides, leading to increased development costs due to high withstanding voltage requirements for connected electric components.
Innovation Solution
A full-bridge resonant conversion circuit design featuring symmetrically disposed resonant inductors in an LLC architecture, with transformers having primary and secondary windings configured to eliminate phase differences and reduce high-frequency oscillations, utilizing MOSFET switches and capacitors for optimized control and reduced voltage surges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional resonant conversion circuits use double transformers with LLC resonant circuits, then power conversion is achieved, but phase differences occur at secondary sides making back-end control difficult
Solution Approach 1:
The patent applies asymmetry by intentionally introducing a phase shift in one of the transformer secondary windings to counterbalance the inherent phase differences caused by the dual-transformer LLC resonant circuit configuration. This compensatory asymmetry restores phase coherence and enables proper synchronization of the synchronous rectification switches, thereby solving the control difficulty while maintaining power conversion capability
2Power
If conventional circuits are used with double transformers, then power conversion is achieved, but high-frequency oscillation occurs at secondary sides requiring high withstanding voltage conditions
Solution Approach 1:
The patent applies preliminary anti-action by introducing a phase-shifting mechanism that proactively counteracts the high-frequency oscillations and voltage surges before they can damage the circuit components. The controlled phase difference compensates for the harmful oscillations, reducing the peak voltage stress on switches and other components, thereby allowing the use of components with lower withstanding voltage ratings
3Power
If phase differences occur at transformer secondary sides, then power conversion continues, but control precision of synchronous rectification is reduced
Solution Approach 1:
The patent applies feedback by implementing a control mechanism that monitors the phase relationships at the transformer secondary sides and dynamically adjusts the switching timing of the synchronous rectification switches. This feedback-based phase compensation ensures precise control despite the presence of multiple transformers and resonant circuits, thereby maintaining high control precision while enabling power conversion
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 solution ensures phase coherence and reduced high-frequency oscillations, enhancing the overall efficiency of the conversion circuit and lowering the withstanding voltage requirements for switches, thereby reducing development costs and improving control precision.
Implementation Method 1
a first secondary winding magnetically coupled with the first primary winding... a second secondary winding magnetically coupled with the second primary winding
Implementation Method 2
a resonant unit comprising a first resonant inductor, a resonant capacitor and a second resonant inductor, wherein the resonant capacitor is connected in series with the first resonant inductor or the second resonant inductor
Data Source
AI summary
A full-bridge resonant conversion circuit comprises a full-bridge rectification unit, a resonant unit, a first transformer, a second transformer and a synchronous rectification unit, wherein the full-bridge rectification unit comprises a first connection end and a second connection end, the resonant unit comprises a first resonant inductor, a resonant capacitor and a second resonant inductor, the resonant capacitor is connected in series with the first resonant inductor or the second resonant inductor. The first transformer comprises a first primary winding connected in series with the first resonant inductor, and a first secondary winding. Also, the second transformer comprises a second primary winding connected in series with the first primary winding and connected with the second resonant inductor, and a second secondary winding connected in parallel with the first secondary winding, and the synchronous rectification unit is connected with the first secondary winding and the second secondary winding.