LLC Resonant Converter Secondary-Series Layout for Branch Balancing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Two-branch LLC resonant circuits experience current or voltage unbalance due to inconsistent resonant parameters, leading to potential component damage and increased complexity with the use of independent switching frequencies for control.
Innovation Solution
The LLC resonant converter system achieves current or voltage equilibrium by connecting secondary side windings of transformers in series, allowing for the same control signal to be used across both branches, regardless of resonant parameter consistency, thus reducing control circuit complexity and expanding component selection range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two independent switching frequencies are used to control the two-branch LLC resonant circuit, then current or voltage equilibrium can be achieved, but the control circuit complexity increases
Solution Approach 1:
The patent merges the control of two-branch LLC resonant circuits into a single unified control system. By connecting the secondary side windings of transformers in series and using one common switching frequency for both branches, the control circuits are combined into one, eliminating the need for two independent control systems while maintaining current or voltage equilibrium between branches.
2Device complexity
If switch transistors are controlled at the same switching frequency, then control circuit complexity is reduced, but output current or voltage unbalance occurs
Solution Approach 1:
By connecting secondary side windings in series, the patent creates an equipotential current path that forces equal current flow through both branches when operated at the same switching frequency. This eliminates output current unbalance while maintaining simple unified control, and similarly prevents voltage unbalance in series-output configurations.
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 ensures balanced output currents or voltages in two-branch circuits, preventing component damage and simplifying control circuitry, while allowing for higher power output without the need for complex frequency control.
Implementation Method 1
LLC (abbreviation of Lr, Lm, and Cr, where Lr refers to a resonant inductor, Lm refers to a magnetic inductor, Cr refers to a resonant capacitor) resonant converter
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Embodiments of the present invention provide an LLC resonant converter system. The LLC resonant converter system includes: a first resonant circuit including a first switch circuit, a first LC resonant circuit, a first transformer, and a first rectifier circuit; and a second resonant circuit including a second switch circuit, a second LC resonant circuit, a second transformer, and a second rectifier circuit; where one secondary side winding of the first transformer is connected in series with one secondary side winding of the second transformer to form a first series branch, and the other secondary side winding of the first transformer is connected in series with the other secondary side winding of the second transformer to form a second series branch. According to the LLC resonant converter system provided in the embodiments of the present invention, current equilibrium or voltage equilibrium in a two-branch resonant circuit is achieved by connecting the secondary side windings of the first transformer and the second transformer in series, thereby simplifying a control circuit and improving current equilibrium or voltage equilibrium effects.