Cross-Connected LLC Resonant Circuit for Current and Voltage Equalization
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Solution Overview
Problem
Conventional LLC resonant converters have limited output power and require additional control circuits for current or voltage equalization when connected in parallel or series, increasing complexity and cost.
Innovation Solution
The LLC resonant conversion circuit connects transformers in a crossed manner to achieve autonomous voltage equalization in series and current equalization in parallel connections without the need for extra control circuits, ensuring consistent current or voltage across harmonic circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple LLC resonant converters are connected in parallel or series to achieve higher output power, then the output power is improved, but additional control circuits for current or voltage equalization are required, increasing device complexity and cost
Solution Approach 1:
The patent divides the system into multiple identical modular LLC resonant converter units, each with standardized transformer connections. This segmentation allows the system to scale in power while maintaining uniform current or voltage distribution across all modules through their symmetric crossed connection topology, eliminating the need for complex centralized control circuits.
Solution Approach 2:
The patent employs an asymmetric crossed connection topology for the transformer windings within each modular unit. This asymmetric arrangement creates inherent current or voltage equalization paths that automatically balance the distribution across parallel or series connected modules without requiring additional control circuitry, thus resolving the contradiction between power scaling and control complexity.
2Power
If multiple LLC resonant converters are connected in parallel or series, then the output power is improved, but the cost increases due to additional equalization control circuits
Solution Approach 1:
By segmenting the system into identical modular units with standardized crossed-connected transformer topologies, the patent enables mass production of standardized modules. This reduces manufacturing costs through economies of scale and eliminates the need for expensive custom control circuits for each multi-module configuration.
Solution Approach 2:
The crossed connection topology of the transformer windings creates self-equalizing characteristics that automatically balance current or voltage distribution across modules. This self-service mechanism eliminates the need for additional active control circuits, reducing component count and manufacturing costs while maintaining reliable power scaling.
3Device complexity
If conventional transformer connections are used in multiple LLC resonant converters, then the circuit structure is simple, but current or voltage equalization cannot be achieved without additional control circuits
Solution Approach 1:
The patent uses an asymmetric crossed connection topology for the transformer windings that creates inherent equalization paths. This asymmetric structure, while maintaining overall circuit simplicity, ensures reliable current or voltage equalization across parallel or series connected modules by providing balanced impedance paths, thus achieving both structural simplicity and operational reliability.
Solution Approach 2:
The crossed connection topology of the transformer windings creates equipotential nodes that naturally equalize current or voltage distribution across multiple LLC resonant converter modules. This topological approach ensures reliable equalization through symmetric potential distribution, maintaining circuit simplicity while achieving dependable operational balance.
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 complexity and cost of the LLC resonant conversion circuit by allowing for equalization of current or voltage without additional components, enhancing the circuit's efficiency and power handling capabilities.
Implementation Method 1
an LC resonant circuit
Implementation Method 2
Lr is a resonant inductor, Lm is an excitation inductor
Implementation Method 3
Cr is a resonant capacitor
Implementation Method 4
a transformer circuit in a first harmonic circuit includes at least three transformers, and each transformer includes a first winding and a second winding
Data Source
AI summary
An LLC resonant conversion circuit includes a plurality of harmonic circuits. In each harmonic circuit, a plurality of transformers are electrically connected to each other and are electrically connected to one transformer in another harmonic circuit, so that the harmonic circuits are connected in a crossed manner. In this way, current or voltage of an electrical signal in one harmonic circuit can be distributed to another harmonic circuit. Without adding any component, this achieves the same current value for electrical signals in the harmonic circuits when the harmonic circuits are connected in parallel, and achieves the same voltage value for electrical signals in the harmonic circuits when the harmonic circuits are connected in series. This effectively reduces complexity of a control policy for the entire LLC resonant conversion circuit and also reduces costs of the LLC resonant conversion circuit.