Transformer Shield and Winding Configuration for Common-Mode Noise Reduction
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Solution Overview
Problem
Current transforming devices for power sources face challenges in reducing common-mode noise, which increases the size and manufacturing cost of transformers and hinders the enhancement of power density due to the complexity and cost of existing noise elimination methods.
Innovation Solution
A transformer design featuring a magnetic element with a first and second winding, where a conductive shield is placed between the windings, and a capacitor is serially connected to the shield and one of the windings to balance common-mode current and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a common mode inductor and capacitor are disposed to eliminate common-mode noise, then the common-mode noise is eliminated, but the size and manufacturing complexity of the device increases
Solution Approach 1:
The patent extracts the common-mode noise elimination function from a separate common-mode inductor and capacitor circuit and integrates it directly into the transformer structure through the third winding connected to ground. This integration eliminates the need for external common-mode filtering components, thereby reducing device complexity while maintaining noise elimination effectiveness.
Solution Approach 2:
The patent merges the common-mode noise elimination function with the existing transformer windings by adding a third winding that is electrically connected to ground. This combines the power transfer function and the common-mode noise suppression function into a single integrated structure, reducing the overall component count and device complexity.
2Object-affected harmful factors
If a common mode inductor and capacitor are disposed to eliminate common-mode noise, then the common-mode noise is eliminated, but the size of the device increases
Solution Approach 1:
The patent merges the common-mode noise elimination function with the existing transformer windings by adding a third winding that is electrically connected to ground. This combines the power transfer function and the common-mode noise suppression function into a single integrated structure, reducing the overall component count and device size.
Solution Approach 2:
The patent extracts the common-mode noise elimination function from a separate common-mode inductor and capacitor circuit and integrates it directly into the transformer structure through the third winding connected to ground. This integration eliminates the need for external common-mode filtering components, thereby reducing device size.
3Object-affected harmful factors
If a differential-mode inductor and capacitor are disposed to eliminate differential-mode noise, then the differential-mode noise is eliminated, but the device complexity and size increase
Solution Approach 1:
The patent merges both common-mode and differential-mode noise elimination functions into the transformer structure itself through the third winding configuration. The third winding's connection to ground provides common-mode suppression, while the transformer's inherent differential-mode rejection characteristics handle differential-mode noise, eliminating the need for separate differential-mode filtering components.
4Volume of moving object
If the size of the inductor is minimized, then the power density requirements are met, but the common-mode noise elimination capability is reduced
Solution Approach 1:
The patent merges the common-mode noise elimination function with the existing transformer windings by adding a third winding that is electrically connected to ground. This combines the power transfer function and the common-mode noise suppression function into a single integrated structure, reducing the overall component count and device size.
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 effectively reduces common-mode noise by 16 dB, minimizing the size and cost of the filter, enhancing power density, and improving efficiency.
Implementation Method 1
The transformer includes a magnetic element, a first winding, a second winding and a shield. The first winding and the second winding are disposed around the magnetic element. The shield is disposed between the first winding and the second winding.
Implementation Method 2
a capacitor is serially connected to the shield and one of the windings to balance common-mode current and reduce noise
Data Source
AI summary
A transformer includes a magnetic element, a first winding, a second winding and a shield. The first winding is wound outside the magnetic element, the second winding is wound outside the first winding, and the shield is disposed between the first winding and the second winding.