Transformer Coil Grouping for Weight Reduction
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Solution Overview
Problem
The existing transformer designs for electric vehicles, particularly those used in railroad applications like the Shinkansen bullet train, face challenges in reducing size and weight while preventing a decrease in reactance, as seen in prior art documents like WO 2010/092676.
Innovation Solution
The transformer is configured with divided coil groups, where high-voltage and low-voltage side coils are wound around legs of a shell-type transformer, allowing for a reduction in size and weight by reducing the number of disc windings and cross-sectional area, and eliminating the need for a second iron core, thus minimizing reactance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second iron core is provided between adjacent coil groups to prevent reactance decrease, then reactance is maintained, but weight increases
Solution Approach 1:
The invention removes the second iron core from between adjacent coil groups, extracting only the necessary magnetic path structure. This eliminates unnecessary weight while maintaining reactance through alternative means (proper coil winding around single-phase legs and shared magnetic paths), resolving the contradiction between reliability and weight.
Solution Approach 2:
The single-phase legs serve multiple functions: they provide magnetic paths for both high-voltage and low-voltage coils, maintain reactance through proper coil arrangement, and eliminate the need for separate second iron cores. This multi-functionality maintains reactance while reducing overall structure weight.
2Power
If the transformer capacity is increased to meet vehicle demands, then power handling capability improves, but size and weight increase
Solution Approach 1:
The transformer is divided into multiple single-phase legs, each handling a portion of the total power. This segmentation allows the transformer to achieve high capacity through parallel operation of multiple smaller units, reducing the weight-to-power ratio compared to a single large-core design.
Solution Approach 2:
The invention transitions from a conventional three-phase core structure to a single-phase leg configuration with multiple independent coils. This dimensional reorganization allows for more efficient space utilization and reduced material requirements, achieving high power capacity with lower weight.
3Length of stationary object
If the transformer height is reduced for low-floor vehicle design, then vehicle floor accessibility improves, but reactance may decrease
Solution Approach 1:
The invention concentrates the magnetic path and coil structures within a compact vertical footprint by using single-phase legs with coils wound around them. This local optimization of magnetic circuit design maintains adequate reactance while achieving reduced overall transformer height for low-floor vehicle applications.
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 configuration achieves a reduction in size and weight while preventing a decrease in reactance, enhancing the transformer's efficiency and performance by reducing power loss and maintaining operational stability during one-side operations.
Implementation Method 1
a plurality of low-voltage side coils provided in correspondence with the high-voltage side coils, magnetically coupled to the corresponding high-voltage side coils
Data Source
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AI summary
A transformer includes an iron core (61) having a plurality of legs, a plurality of high-voltage side coils each wound around one of the plurality of legs, and a plurality of low-voltage side coils provided in correspondence with the high-voltage side coils, and each wound around one of the plurality of legs. The high-voltage side coils and the corresponding low-voltage side coils form a plurality of coil groups. A first coil group (G1) of the plurality of coil groups includes one of the high-voltage side coils (1A) and one of the low-voltage side coils (2A) wound around a first leg (31) of the plurality of legs, and one of the high-voltage side coils (1B) and one of the low-voltage side coils (2B) wound around a second leg (32) adjacent to the first leg (31) of the plurality of legs. A second coil group (G2) of the plurality of coil groups includes one of the high-voltage side coils (11A) and one of the low-voltage side coils (12A) wound around the first leg (31), and one of the high-voltage side coils (11B) and one of the low-voltage side coils (12B) wound around the second leg (32).