Toroidal Common Mode Choke Winding for High-Frequency EMI Suppression
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Solution Overview
Problem
Existing common mode chokes face challenges in providing sufficient common mode impedance in high-frequency and high-voltage scenarios without increasing the adapter's volume, as traditional winding methods like C-type and Z-type methods have insufficient impedance in the high-frequency band, and butterfly-type methods still fall short in such conditions.
Innovation Solution
A common mode choke structure featuring a toroidal magnetic core with N windings that are rotationally symmetric, where each winding has distinct groups with varying numbers of winding sections and layers, and opposite winding directions at the starting point, effectively increasing impedance and reducing parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the effective area of core (Ae) value is increased to increase common mode impedance, then the common mode impedance is improved, but the volume of the adapter increases and power density decreases
Solution Approach 1:
The patent changes the winding parameters (number of winding sections, layers per section, winding direction) to optimize the common mode impedance characteristics without changing the core effective area, thereby maintaining small volume while achieving high impedance
Solution Approach 2:
The patent uses asymmetric winding configuration where the first and second groups of windings have different numbers of winding sections and/or different numbers of layers, creating asymmetric current distribution that enhances common mode impedance while maintaining compact size
2Ease of manufacture
If traditional winding methods (C-type, Z-type) are used, then the manufacturing is simple, but the impedance in high frequency band is insufficient and filtering effect is poor
Solution Approach 1:
The patent divides each winding into multiple winding sections (first group and second group) with different configurations, where each section contributes to the overall impedance characteristics, achieving high-frequency suppression through segmented current paths while maintaining manufacturability
Solution Approach 2:
The patent introduces an additional dimension of complexity by varying the number of layers in different winding sections, creating a three-dimensional winding structure that enhances high-frequency impedance without significantly complicating the manufacturing process
3Reliability
If butterfly-type winding method is used, then parasitic capacitance between turns is reduced and high-frequency impedance is increased, but impedance in high frequency band is still insufficient for high-frequency switch scenarios
Solution Approach 1:
The patent applies different winding configurations (different numbers of sections and layers) to different parts of the same winding, creating local variations in current distribution and impedance characteristics that collectively enhance high-frequency performance
Solution Approach 2:
The patent creates a universal winding structure that can handle both common mode noise suppression and high-frequency switch scenarios simultaneously by using rotationally symmetric configurations with multiple winding sections that provide broadband impedance enhancement
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 enhances common mode impedance and electromagnetic interference filtering capabilities without increasing the adapter's volume, providing better EMI noise suppression in high-frequency and high-voltage applications.
Implementation Method 1
a toroidal magnetic core and N windings wound on the toroidal magnetic core... configured to suppress common mode interference
Implementation Method 2
The parasitic capacitance advances a resonance point of a common mode choke, making the choke capacitive at a high frequency
Data Source
AI summary
A common mode choke includes a toroidal magnetic core and N windings wound on the toroidal magnetic core. The N windings are rotationally symmetric in a central direction of the toroidal magnetic core. Each of the N windings includes two lead ends which are respectively located at outermost layers of two sides of each winding. Each of the N windings includes a first group of windings and a second group of windings. A starting point of each of the N windings is located between the first group of windings and the second group of windings. A quantity of winding sections in the first group of windings is different from a quantity of winding sections in the second group of windings. Each winding section in both the first group of windings and the second group of windings includes a plurality of winding layers. Each winding layer includes a plurality of coils.