Integrated Magnetic Core Layout for LLC Current Balance
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Solution Overview
Problem
Conventional integrated magnetic components for LLC resonant converters are not suitable for three-phase converters due to current and magnetic flux imbalances, and they require a high amount of expensive magnetic material, resulting in high weight, volume, and cost.
Innovation Solution
An integrated magnetic component comprising at least one first type magnetic core element with three legs and at least one second type magnetic core element with five legs, stacked such that their legs are arranged in a row, with the second type core elements providing return legs to compensate for current and magnetic flux imbalances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional stacked E-core arrangements are used, then the magnetic component can be assembled, but current and magnetic flux imbalances occur in three-phase converters
Solution Approach 1:
The patent applies asymmetry by using magnetic core elements with different numbers of legs (first type with three legs, second type with five legs). This asymmetric configuration allows the five-legged cores to provide additional return legs that compensate for current imbalances and magnetic flux imbalances in three-phase converters, while maintaining ease of assembly through the standardized stacking approach.
2Reliability
If stacked W-core arrangements are used for three-phase converters, then current and magnetic flux imbalances are compensated, but a high amount of magnetic material is required
Solution Approach 1:
The patent segments the magnetic core structure into two distinct types: first type magnetic core elements with three legs and second type magnetic core elements with five legs. This segmentation allows selective use of five-legged cores only where needed for imbalance compensation, rather than requiring all cores to be five-legged as in conventional W-core arrangements, thereby reducing total magnetic material weight.
Solution Approach 2:
The patent applies local quality by providing return legs (additional legs) only in specific locations where current and magnetic flux imbalances occur. The five-legged magnetic core elements are strategically positioned to provide local compensation for imbalances in three-phase converters, rather than uniformly increasing the size of all magnetic cores throughout the structure.
3Device complexity
If conventional magnetic components are used, then the structure is simple, but volume and weight are high
Solution Approach 1:
The patent merges multiple functions into the magnetic core structure by combining choke and transformer functions in a single integrated component. The stacked arrangement of different types of magnetic core elements allows the structure to simultaneously provide magnetic flux paths for both choke and transformer operations, reducing overall volume compared to separate components.
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 proposed solution reduces the weight, volume, and cost of the magnetic component while effectively compensating for current and magnetic flux imbalances, leading to increased thermal and electric efficiency and reduced losses, particularly iron losses.
Implementation Method 1
the return legs, around which no winding is wound, together with the yoke close a magnetic circuit generated by a magnetic flux by the windings of the winding legs
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention concerns an integrated magnetic component (1) for a converter (100, 110), comprising: at least one first type magnetic core element (2) comprising a yoke (4) and at least three legs (5, 6), wherein a first total number of legs (5, 6) is defined as a number of said legs (5, 6) of each of said at least one first type magnetic core element (2); at least one second type magnetic core element (3) comprising a yoke (4) and at least three legs (5, 6) wherein a second total number of legs (5, 6) is defined as a number of said legs (5, 6) of each of said at least one second type magnetic core element (3); wherein at least one first type magnetic core element (2) and at least one second type magnetic core element (3) are stacked one on another along a stacking direction (8) such that their legs (5, 6) are arranged in row, the first total number of legs (5, 6) and the second total number of legs (5, 6) are each an addition of a respective number of winding legs (5), around which electric winding (7) is wound, with a number of return legs (6), around which no electric winding (7) is wound, and the first total number of legs (5, 6) and the second total number of legs (5, 6) are non-equal. The invention also concerns a unidirectional LLC resonant converter (100) and a bidirectional LLC resonant converter (110).