Hybrid-Material Current Sensing Transformer With Low Winding Ratio
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Solution Overview
Problem
Current sensing transformers are limited by size and cost, with traditional designs being larger and more expensive than resistive sensors, and face issues with self-inductance, magnetic saturation, and signal distortion at high frequencies due to high winding ratios.
Innovation Solution
The use of hybrid materials with thin insulation layers and high permeability allows for smaller, more accurate current sensing transformers with a primary to secondary winding ratio greater than 1, incorporating an LC tank circuit for AC and DC current sensing, and integration into semiconductor packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high winding ratio (1:10 to 1:1000) is used in current sensing transformer, then measurement accuracy is improved, but self-inductance, magnetic saturation, and signal distortion increase at high frequencies
Solution Approach 1:
The patent changes the winding ratio parameter from traditional high ratios (1:10 to 1:1000) to low ratios (greater than 1:1), which fundamentally alters the transformer's electrical characteristics. This parameter change reduces self-inductance and magnetic saturation effects while maintaining measurement accuracy through the use of multiple primary windings and advanced signal processing
Solution Approach 2:
The patent employs a composite core structure combining magnetic material with non-magnetic material. This composite construction optimizes magnetic flux distribution, reduces magnetic saturation, and improves high-frequency performance while maintaining the low winding ratio design
2Measurement precision
If primary windings are increased to maintain current sensing capability, then current sensing accuracy is improved, but transformer size increases significantly
Solution Approach 1:
The patent inverts the traditional transformer design by using more primary windings than secondary windings (ratio greater than 1:1), whereas conventional designs use many more secondary windings. This inversion allows accurate current sensing with fewer total windings, significantly reducing transformer size while maintaining measurement precision
Solution Approach 2:
The patent makes the magnetic core serve multiple functions: it provides magnetic flux path for induction, acts as a structural support for windings, and functions as part of the shielding system. This multi-functionality reduces the need for separate components, minimizing overall transformer size
3Measurement precision
If high winding ratio is used to achieve accurate current measurement, then measurement accuracy is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent inverts the winding ratio from traditional high ratios to low ratios (greater than 1:1), which dramatically reduces the number of secondary windings required. This inversion simplifies the winding process, reduces manufacturing complexity, and lowers production costs while maintaining measurement accuracy through multiple primary windings
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 solution enables compact, high-performance current sensing transformers that maintain accuracy and stability, reducing manufacturing costs and size, suitable for a wide range of current and frequency applications, and compatible with semiconductor packaging.
Implementation Method 1
current can be sensed in a system by utilizing the magnetic field it creates. In general, this is achieved in alternating current systems by using the magnetic field to induce voltage or current in another system
Implementation Method 2
hybrid materials with thin insulation layers and high permeability
Data Source
AI summary
Utilizing hybrid materials in a current sensing transformer with primary to secondary coil ratios greater than one is possible and practical. The ease of manufacture associated with this method allows almost any inductor of any size to be converted into a current sensing transformer without significantly increasing the size, cost, or time of manufacture or affecting the performance of the inductor itself. The result is low-cost, high-performance AC and DC current sense components.