Interleaved LLC Converter Active Balancing
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Solution Overview
Problem
Interleaved LLC power converters face challenges in current sharing between power stage channels due to manufacturing and temperature variations, leading to mismatches in resonant components, which affect output voltage and current levels.
Innovation Solution
An active balancing technique is employed to adjust independent power inputs of each LLC power stage to match output voltage and current levels for a given load condition and common operating frequency, using a compensation controller to modulate pre-regulator outputs and phase angles between channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If interleaved LLC power converters are used to increase output power capability, then productivity is improved, but current sharing between channels deteriorates due to resonant component mismatches
Solution Approach 1:
The patent changes the operating parameters of each LLC power converter channel by adjusting the phase angle of the modulation signal independently for each channel. This allows the resonant components to operate at optimized points that compensate for manufacturing variations, enabling current sharing without requiring tightly matched components. The phase angle adjustment modifies the resonant frequency and impedance characteristics of each channel dynamically.
2Reliability
If resonant components are tightly matched to ensure current sharing, then current sharing is improved, but manufacturing precision requirements increase
Solution Approach 1:
The system performs self-adjustment by automatically detecting the actual current output of each channel and dynamically adjusting the phase angle of the modulation signal for that channel. This closed-loop self-service mechanism compensates for component variations without requiring external calibration or manual adjustment, allowing standard tolerance components to be used while maintaining balanced current sharing.
3Reliability
If additional regulation stages are added to balance output levels, then current sharing is improved, but device complexity increases
Solution Approach 1:
The modulation phase angle control mechanism serves multiple functions simultaneously: it regulates the output voltage level of each channel, balances the current sharing between channels, and optimizes the efficiency of the resonant converter. This multi-functionality eliminates the need for separate regulation stages, as the phase angle adjustment performs both voltage regulation and current balancing in a unified control approach.
Data Source
AI summary
An interleaved LLC converter, a method of operating an LLC converter and a power supply are disclosed herein. In one embodiment, the LLC converter includes: (1) a plurality of LLC power channels, with each of the plurality having an independent power input and (2) a compensation controller configured to actively adjust the independent power inputs to substantially match output voltage and current levels for a given load condition and a common operating frequency of the plurality of LLC power channels.