LLC Resonant Converter Transformer with Integrated Inductance
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Solution Overview
Problem
Existing LLC resonant converters face challenges in achieving high power density due to insufficient leakage inductance, particularly in planar transformers, which often require external inductors to secure resonance, increasing system size and complexity.
Innovation Solution
A transformer design with first and second cores and inductor winding parts that generate middle and outer foot inductances, allowing for resonance operation without external inductors, enabling zero voltage switching and high frequency driving by utilizing the magnetic field formed between the cores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a planar transformer is used to reduce the physical size of the transformer, then the power density is improved, but the leakage inductance becomes insufficient for resonance operation
Solution Approach 1:
The transformer is divided into multiple magnetic cores (first core, second core, third core, fourth core) arranged in a specific configuration. Each core contributes to the overall leakage inductance, allowing the planar structure to maintain sufficient resonance inductance while keeping the physical size reduced. The segmentation of magnetic paths enables independent control of leakage inductance characteristics.
Solution Approach 2:
The patent applies different winding configurations to different parts of the transformer structure. Specifically, the first and second windings are connected in series to enhance leakage inductance in critical regions, while maintaining the planar form factor. This local differentiation of winding structures ensures that leakage inductance is sufficient for resonance operation without increasing overall transformer size.
2Reliability
If external inductors are added to secure resonance inductance, then the resonance operation is improved, but the system size and complexity increase
Solution Approach 1:
The patent merges the resonance inductor function with the transformer structure itself. By configuring the windings and magnetic cores to generate sufficient leakage inductance, the transformer simultaneously performs power transformation and provides the necessary resonance inductance. This eliminates the need for separate external inductors, reducing system complexity and part count while maintaining stable resonance operation.
Solution Approach 2:
The transformer is designed to serve multiple functions: power transformation, voltage isolation, and providing resonance inductance. The series-connected windings and specific core arrangement enable the transformer to generate adequate leakage inductance for resonance operation, making it a multi-functional component that eliminates the need for dedicated external resonance inductors.
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 design eliminates the need for separate external inductors, ensuring stable operation and high power density by directly setting equivalent resonance and magnetized inductances, facilitating efficient power control and miniaturization of the power conversion apparatus.
Implementation Method 1
first and second inductor winding parts configured to include a conductor surrounding a circumference of each of the pair of outer foots of the first core, and to be connected in series with each other; and first and second transformer winding parts configured to include a conductor surrounding a circumference of each of the pair of outer foots of the second core
Implementation Method 2
first and second cores configured to include a pair of outer foots and a middle foot positioned between the outer foots, and to induce a magnetic field formation
Data Source
AI summary
A transformer and an LLC resonant converter are provided. The transformer includes first and second cores configured to include a pair of outer foots and a middle foot positioned between the outer foots, and to induce a magnetic field formation; first and second inductor winding parts configured to include a conductor surrounding a circumference of each of the pair of outer foots of the first core, and to be connected in series with each other; and first and second transformer winding parts configured to include a conductor surrounding a circumference of each of the pair of outer foots of the second core, wherein the pair of outer foots of the first core face the pair of outer foots of the second core, the middle foot of the first core faces the middle foot of the second core, and the first core and the second core are disposed to be spaced apart from each other.