Common Mode Inductor With Segmented Coil Windings
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Solution Overview
Problem
Conventional EMI filter circuits fail to meet miniaturization and high-frequency operation requirements due to insufficient EMI suppression ability of common mode inductors, leading to increased reliance on additional suppression devices.
Innovation Solution
A common mode inductor apparatus with coil windings in multiple winding areas of a magnetic core, where each winding area is separated by gaps, enhancing EMI suppression and reducing parasitic capacitance for improved high-frequency filtering without increasing the number of turns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional two-stage EMI filter circuit is used to suppress EMI noise, then EMI suppression ability is improved, but the space occupied by the circuit increases due to multiple common mode inductors and capacitors
Solution Approach 1:
The patent combines multiple winding areas into a single common mode inductor apparatus, merging the functions of multiple inductors into one integrated structure. The magnetic core includes multiple winding zones with coil windings arranged in different areas, allowing the apparatus to provide enhanced EMI suppression while occupying less space than conventional multi-inductor configurations
Solution Approach 2:
The patent segments the coil windings into multiple distinct winding areas separated by gaps. Each winding area is positioned in a different zone of the magnetic core, creating spatial separation that reduces parasitic capacitance while maintaining compact overall structure. This segmentation allows the single apparatus to achieve performance equivalent to or better than multiple separate inductors
2Ease of manufacture
If symmetrically winding two coils on a closed magnetic core is used, then manufacturing simplicity is improved, but EMI suppression ability deteriorates due to poor filtering performance
Solution Approach 1:
The patent applies local quality by creating different winding configurations in different zones of the magnetic core. The coil windings are arranged in multiple distinct areas with different spatial relationships to the magnetic flux paths, giving each winding area specialized filtering characteristics. This local differentiation enhances overall EMI suppression while maintaining manufacturing feasibility through systematic winding patterns
3Reliability
If the number of turns of coil windings is increased to improve EMI suppression, then EMI suppression ability is improved, but parasitic capacitance increases leading to degraded high-frequency filtering
Solution Approach 1:
The patent transitions from a single-plane winding arrangement to a multi-dimensional configuration by distributing coil windings across multiple spatial zones of the magnetic core. The gaps between winding areas and the three-dimensional arrangement of windings around the magnetic core reduce parasitic capacitance effects while maintaining effective inductance for EMI suppression across a broader frequency range
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 proposed solution increases EMI suppression ability and reduces the space occupied by the EMI filter circuit, meeting miniaturization and high-frequency operation requirements while maintaining low parasitic capacitance and effective filtering.
Implementation Method 1
reduces parasitic capacitance for improved high-frequency filtering
Implementation Method 2
a common mode inductor is one of the main EMI suppression devices in the EMI filter circuit
Data Source
AI summary
A common mode inductor apparatus includes a magnetic core, a first coil winding and a second coil winding. The magnetic core has a first winding zone and a second winding zone. The first coil winding is wound in three winding areas within the first winding zone, wherein two neighboring winding areas within the first winding zone are separated by a gap. The second coil winding is wound in three winding areas within the second winding zone, wherein two neighboring winding areas within the second winding zone are separated by a gap.