Parallel LLC Converter Startup for Current Balancing
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Solution Overview
Problem
Existing converter circuits for high-power electronic devices require current balancing among multiple LLC resonant converters, which is typically achieved through load share circuits or passive schemes, leading to increased volume and cost.
Innovation Solution
A converter circuit design that includes two LLC resonant converters sharing a resonant capacitor, controlled by a unit to activate them sequentially with a time interval, reducing inrush voltage on leakage inductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple LLC resonant converters are connected in parallel for high power applications, then power capability is improved, but current balancing becomes complex requiring additional load share circuits
Solution Approach 1:
The patent extracts and eliminates the load share circuit from the system by using a passive current balancing scheme based on resonant frequency differences. Each converter operates at its own resonant frequency, allowing natural current distribution without additional active balancing components.
Solution Approach 2:
The converters self-regulate their current distribution through passive elements (inductors and capacitors) in their output stages. The converter with higher output voltage naturally supplies more current, and the passive elements prevent overcurrent, enabling self-balancing without external control circuits.
2Speed
If simultaneous switching of multiple converters is performed, then activation speed is improved, but inrush voltage on leakage inductors increases
Solution Approach 1:
The patent applies preliminary action by sequentially activating converters rather than simultaneously. The first converter is activated and stabilized before the second converter is switched on, preventing inrush voltage spikes that would occur with simultaneous switching.
Solution Approach 2:
The patent uses periodic action through sequential activation with time intervals between converter switching. This staged approach allows each converter to settle into its operating state before the next one is activated, reducing electrical transients.
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 effectively balances current among converters while minimizing manufacturing costs and volume, reducing inrush current magnitude.
Implementation Method 1
a first converter circuit having a resonant capacitor and including a first leakage inductor and a first transformer
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
The present disclosure relates to an electronic device comprising a converter circuit for current balancing, and a control method therefor. The electronic device may comprise a plurality of half-bridge converters connected in parallel to share a resonance capacitor. The electronic device can control a first half bridge unit included in a first converter circuit and a second half bridge circuit included in a second converter unit such that the first converter circuit and the second converter unit can be sequentially started at a first time interval (td).