Magnetic Integrated Device for Three-Phase Current Equalization

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Solution Overview

Problem

In three-phase parallel LLC power supply conversion circuits, current equalization across branches is not guaranteed due to parameter drifts in components, leading to potential device failure.

Innovation Solution

A magnetic integrated device with a specific configuration of magnetic core bases and columns, where windings are wound in a manner to form closed magnetic flux loops and superposed to create a coupling relationship for magnetic flux interaction, allowing automatic current equalization across branches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If three identical LLC resonant circuits are connected in parallel to reduce ripple current, then the ripple current is reduced theoretically, but parameter drift in components causes current unequalization and potential device failure

Engineering Contradiction:
Improvecurrent equalizationVSAvoidcircuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines three separate LLC resonant circuits into a single integrated magnetic structure with shared magnetic cores and coupled windings. The primary windings of the three circuits are wound on common magnetic core columns, creating magnetic coupling that automatically equalizes currents across all three phases without requiring separate control circuits or additional balancing components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The magnetic coupling structure enables automatic current equalization through self-regulating magnetic flux interaction. When current drift occurs in one phase, the magnetic coupling automatically induces compensating effects in the other phases, causing the system to self-correct without external intervention or complex control mechanisms.

Inventive Principle:
Principle #25Self-service

2Device complexity

If magnetic cores are integrated to reduce component count, then device complexity is reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvenumber of magnetic componentsVSAvoidmagnetic core assembly
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent integrates three separate magnetic core structures into a single assembled unit with shared magnetic core bases and columns. The first and second magnetic core bases support three magnetic core columns each, with windings from different circuits coupled on the same columns, reducing the total number of discrete magnetic components while maintaining electrical isolation between phases.

Inventive Principle:
Principle #5Merging (Combining)

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 magnetic integrated device ensures automatic current balancing across all branches by adjusting magnetic flux, preventing parameter drift-induced imbalances and potential device failure.

Implementation Method 1

a first magnetic core column, a second magnetic core column, and a third magnetic core column that are located between the first magnetic core base and the second magnetic core base; a first winding, a second winding, and a third winding are wound on the first magnetic core column, the second magnetic core column, and the third magnetic core column respectively in a same winding manner to form a closed magnetic flux loop

Methodology Applied
Scientific EffectMagnetic flux interaction: Electromagnetic Induction

Implementation Method 2

a fourth winding, a fifth winding, and a sixth winding are superposed and wound on the first winding, the second winding, and the third winding respectively in a same manner; a pair of windings on each magnetic core column of the first magnetic core column, the second magnetic core column, and the third magnetic core column are usable as a primary side and a secondary side of a transformer

Methodology Applied
Scientific EffectMagnetic coupling: Electromagnetic Induction

Data Source

PatentEP3054593B1Magnetic integrated device and power conversion circuit
Publication Date: 2021.06.09 HUAWEI TECH CO LTD
  • EP3054593B1 patent drawingFigure 1~2
  • EP3054593B1 patent drawingFigure 3
  • EP3054593B1 patent drawingFigure 4

AI summary

Embodiments of the present invention disclose a magnetic integrated device and a power conversion circuit. The magnetic integrated device includes: a first magnetic core base and a second magnetic core base that are parallel and a first magnetic core column, a second magnetic core column, and a third magnetic core column that are located between the first magnetic core base and the second magnetic core base; and a first winding, a second winding, and a third winding are wound on the first magnetic core column, the second magnetic core column, and the third magnetic core column respectively in a same manner to form a closed magnetic flux loop, where the first winding, the second winding, and the third winding are separately used for connecting to a branch of a three-phase parallel circuit, and in all branches of the three-phase parallel circuit, values of currents are the same, and a difference between each two current phases is 120 degrees. In the present invention, branches of a three-phase parallel circuit interact, in a magnetic integrated device, with one another by using a coupling relationship of magnetic flux, and a change in magnetic flux in one branch results in a simultaneous adjustment in the other two branches, thereby implementing automatic current equalization, and achieving an effect of automatically balancing currents in all branches.