Segmented Rotary Transformer Core for Weight and Loss Reduction
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Solution Overview
Problem
Existing rotary transformers in weight-critical applications face challenges such as difficulty in constructing laminated cores, limited tolerance to mechanical displacements, and increased weight due to robustness requirements, which affect efficiency and reliability in transferring electrical power between rotating parts in aerospace and wind turbine systems.
Innovation Solution
A rotary transformer design featuring a primary core divided into discrete, equi-spaced segments and a secondary core with a substantially annular configuration, allowing for easy lamination and reduced weight, with magnetic flux passing radially or axially between the cores to maintain efficiency and tolerance to displacements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional annular transformer configuration is used, then power transfer capability is achieved, but the core construction becomes difficult and weight increases due to robustness requirements
Solution Approach 1:
The transformer core is divided into multiple discrete segments arranged in a circular array about the rotation axis. Each segment contains a portion of the primary and secondary windings. This segmentation enables easier lamination construction of each individual segment, reducing eddy-current losses while simplifying manufacturing compared to a solid annular core.
2Strength
If robust core construction is implemented, then mechanical strength is improved, but device weight increases
Solution Approach 1:
By dividing the core into discrete segments, each segment can be optimized for minimum necessary strength rather than requiring the entire core structure to be overly robust. This reduces overall material usage and weight while maintaining sufficient mechanical strength for the application.
Solution Approach 2:
The transformer is designed to accommodate dynamic conditions including rotation and mechanical displacements. The segmented core configuration with proper magnetic coupling maintains functionality under dynamic operation, allowing lighter construction compared to static robust designs.
3Ease of manufacture
If core segments are used, then manufacturing ease and weight are improved, but tolerance to mechanical displacements may be affected
Solution Approach 1:
The segmented core design with properly positioned segments maintains magnetic coupling under mechanical displacements. Each segment is positioned to ensure continuous magnetic flux paths are maintained during rotation and displacement, providing tolerance to mechanical variations while enabling easy lamination construction.
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 design enhances efficiency by reducing eddy-current losses, improves tolerance to mechanical displacements, and minimizes weight, making it suitable for weight-critical applications while maintaining reliable power transfer.
Implementation Method 1
Power transfer across the air gap is achieved by applying a time-varying voltage to the transformer's primary coil 5. This causes a time-varying current to flow through the primary coil 5, which establishes a time-varying magnetic flux in the transformer core.
Implementation Method 2
The configuration illustrated in Figure 2 shows the flux travelling axially between the primary and secondary cores and a time-varying voltage is thus induced in the secondary coil 10
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A rotary transformer is disclosed which comprises a primary core (15) having a primary coil (17) wound thereon, and a secondary core (16) having a secondary coil (19) wound thereon, wherein said cores (15) are mounted for relative rotation about an axis of rotation (14). The transformer (11) being characterised in that one of said cores (15) comprises a plurality of core segments (15a, 15b, 15c, 15d) arranged in spaced-apart relation relative to one another in a substantially circular array about said axis (14), the other core (17) having a substantially annular configuration. In a particular embodiment, said primary core (15) is fixed and hence remains static during operation, and comprises a plurality of spaced apart core segments arranged in a circular array around said axis.