Multiphase LLC Resonant Converter Current Balancing Layout
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Solution Overview
Problem
Existing multiphase LLC resonant converters face challenges in balancing currents between parallel conversion circuits due to varying excitation inductances of transformers, which hinder achieving higher electrical power and integration.
Innovation Solution
The implementation of adjustment inductors connected in parallel with the primary windings of each conversion circuit, along with a common neutral point connection for resonant capacitors, ensures balanced currents across multiple conversion circuits, allowing for higher electrical power and integration without rewinding transformers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of conversion circuits is increased to achieve higher electrical power, then the electrical power is improved, but the currents become unbalanced between the conversion circuits due to varying excitation inductances
Solution Approach 1:
An adjustment inductor is introduced as an intermediary component connected in parallel with the primary winding of each transformer. This adjustment inductor acts as a mediator to regulate and balance the excitation inductance across multiple conversion circuits, ensuring uniform current distribution while allowing the system to operate at higher power levels with multiple parallel circuits
2Device complexity
If the number of conversion circuits is increased to achieve higher integration, then the integration level is improved, but the currents become unbalanced between the conversion circuits
Solution Approach 1:
The adjustment inductor serves as a compensating intermediary that enables higher integration of multiple conversion circuits in parallel while maintaining current balance. By connecting the adjustment inductor in parallel with each transformer's primary winding, the system achieves better integration without sacrificing current distribution uniformity
3Reliability
If adjustment inductors are added to balance currents, then the current balance is improved, but the device complexity increases
Solution Approach 1:
The adjustment inductors are designed with uniform specifications and are connected in a standardized parallel configuration with each transformer primary winding. This homogeneous arrangement simplifies the overall circuit design and manufacturing process, reducing the practical complexity increase despite adding balancing functionality
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 solution effectively balances currents, enabling higher electrical power and integration while reducing the size of resonant inductors and maintaining uniform resonance frequency, even with varying capacitor values, and supports applications like EV quick charge stations.
Implementation Method 1
LLC resonant converter to convert an input voltage into an output voltage using a plurality of LLC resonant converters
Implementation Method 2
a transformer including a primary winding and a secondary winding
Data Source
AI summary
A multiphase LLC resonant converter of N phases (N represents an integer equal to or more than two) causes N resonant converters connected in parallel to a direct current power supply to operate with a phase difference of 360°/N. One of the resonant converters includes a lower adjustment inductor connected in parallel with primary windings of the lower conversion circuits. The one of the resonant converters includes an upper adjustment inductor connected in parallel with primary windings of upper conversion circuits. Outputs including high potential output terminals and low potential output terminals of the lower conversion circuits and the upper conversion circuits star connected at neutral points via a second resonant capacitor are connected.