LLC Converter Circuit With Resonant Voltage Equalization

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Solution Overview

Problem

The existing wide range constant power converter faces issues with voltage equalization and non-monotonic gain under light load conditions, particularly due to parameter deviations and changes in pulse control of the LLC resonant converter, leading to unstable output voltage and secondary capacitor deviations.

Innovation Solution

The converter circuit incorporates resonant voltage equalization networks at the secondary side of the transformer and parameter voltage equalization networks at the primary side, along with a high and low voltage mode control module to manage connections in series or parallel configurations, ensuring stable voltage equalization across capacitors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single converter circuit is used to cover a wide input voltage range, then the device complexity is reduced, but the converter cannot maintain optimal efficiency and regulated output voltage across the entire range

Engineering Contradiction:
Improveinput voltage rangeVSAvoidconverter circuit structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The converter circuit is divided into multiple independent converter circuits, each optimized for a specific input voltage range. The system includes a first converter circuit for a first voltage range and a second converter circuit for a second voltage range, allowing each segment to operate at peak efficiency within its designated range while collectively covering the full wide input voltage range.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically selects which converter circuit to operate based on the current input voltage level. The controller monitors the input voltage and switches between the first and second converter circuits as the voltage transitions between ranges, ensuring optimal performance across the entire operating spectrum.

Inventive Principle:
Principle #15Dynamics

2Reliability

If multiple converter circuits are used for different voltage ranges, then efficiency and voltage regulation are improved, but the device complexity increases

Engineering Contradiction:
Improveoutput voltage regulationVSAvoidconverter circuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple converter circuits are merged into a single integrated converter assembly that functions as one unified system. The converter circuits share common components including output capacitor, inductor, and controller, reducing overall system complexity while maintaining the benefits of range-specific optimization.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Each converter circuit is designed with universal components that can serve multiple functions. The shared inductor, capacitor, and control architecture allow the system to handle different voltage ranges using a common structural framework, reducing the complexity increase that would normally accompany multiple dedicated circuits.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If the converter operates at the boundary between voltage ranges, then the output voltage may become unregulated, but using separate circuits for each range improves regulation

Engineering Contradiction:
Improveoutput voltage regulationVSAvoidvoltage range coverage
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The controller is configured to anticipate the transition between voltage ranges and proactively switches between converter circuits before the boundary is reached. This preliminary action prevents the unregulated output voltage condition that occurs at range boundaries in conventional systems, ensuring continuous stable operation across the entire voltage spectrum.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system employs feedback control through the controller that monitors input voltage levels and automatically adjusts which converter circuit is active. This feedback mechanism ensures seamless transitions between ranges and maintains regulated output voltage by selecting the appropriate converter circuit based on real-time voltage conditions.

Inventive Principle:
Principle #23Feedback

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 effectively addresses voltage deviations and ensures stable output voltage across a wide range, maintaining constant power delivery under varying load conditions.

Implementation Method 1

a second inductor (420) coupled to the second switch (402) and the third terminal (406)

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

a first capacitor (408) coupled in parallel to the load (404)

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4064544B1Ultra-wide-range high-power converter circuit
Publication Date: 2026.05.06 SHENZHEN UU GREEN POWER CO LTD
  • EP4064544B1 patent drawingFigure 1~2B
  • EP4064544B1 patent drawingFigure 3
  • EP4064544B1 patent drawingFigure 4~5

AI summary

Disclosed is a converter circuit having high power in an ultra-wide range, which includes a transformer module, a first and second primary input modules, an output module, a high and low voltage mode control module, and a load output module. The first primary input module includes a first primary voltage equalization network, a first switch module and a first LC module, the second primary input module includes a second primary voltage equalization network, a second switch module and a second LC module. The first primary voltage equalization network is connected between a first input capacitor and the second switch module, and the second primary voltage equalization network is connected between a second input capacitor and the first switch module. In this disclosure, it is surprisingly found that through arranging resonant voltage equalization network, a designated primary voltage deviation problem, which is caused by a change of a pulse control of an LLC resonant converter under a light load, is solved.