Damping Conductor Structure for High-Frequency EMI Suppression
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Solution Overview
Problem
Power electronic systems with high capacity and power density face high EMI noise issues due to fast switching speeds and parasitic parameters, leading to potential device failure and EMC compliance violations.
Innovation Solution
A conductor with a damping function is introduced, featuring a damping material with varying resistances at different frequencies and surface roughness to direct high-frequency currents through high-resistance paths, reducing noise by leveraging the skin and proximity effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If fast switching speed is used to achieve high power density, then power density is improved, but EMI noise increases
Solution Approach 1:
The conductor surface is modified with localized damping material coating or roughness treatment to create different electrical properties at different locations. This local modification increases high-frequency resistance at the conductor surface where EMI noise propagates, while maintaining low overall resistance for power transmission, thus reducing EMI noise without compromising power density
Solution Approach 2:
The conductor's surface resistance parameter is changed by applying damping material or creating surface roughness. This parameter change increases resistance at high frequencies (above 1MHz) to dampen EMI noise, while the bulk conductor maintains low resistance for efficient power transmission, resolving the contradiction between fast switching and EMI reduction
2Object-generated harmful factors
If EMI filters are added to reduce EMI noise, then EMI noise is reduced, but system complexity and size increase
Solution Approach 1:
The EMI damping function is merged directly into the conductor structure by applying damping material coating or surface roughness treatment. This integration eliminates the need for separate EMI filters, reducing system complexity and size while maintaining EMI reduction effectiveness. The conductor simultaneously performs power transmission and EMI damping functions
Solution Approach 2:
The conductor is designed to perform multiple functions: power transmission and EMI noise damping. By incorporating damping material or surface roughness, the conductor becomes a multi-functional component that reduces EMI noise without requiring additional filtering components, thus simplifying the overall system
3Object-generated harmful factors
If damping material is applied to increase high-frequency resistance, then EMI noise is reduced, but low-frequency power transmission efficiency may be affected
Solution Approach 1:
The damping effect is localized to the conductor surface through thin coating or surface roughness treatment, while the bulk conductor maintains high conductivity. This local modification increases high-frequency resistance for EMI damping without significantly affecting low-frequency power transmission, minimizing power loss
Solution Approach 2:
The conductor's resistance parameter is frequency-dependent due to the damping material or surface roughness. At high frequencies (above 1MHz), resistance increases to dampen EMI noise. At low frequencies, the bulk conductor's low resistance dominates, ensuring efficient power transmission with minimal energy loss
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 conductor effectively reduces high-frequency EMI noise, enhancing efficiency, power density, and reliability of power electronic systems while complying with EMC regulations.
Implementation Method 1
The damping part forms first and second paths for first and second power currents flowing between the power components respectively, the first power current is at a frequency higher than 1MHz, the second power current is at a frequency lower than 1MHz
Implementation Method 2
reducing noise by leveraging the skin and proximity effects
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~5
AI summary
A power electronic system with conductor (1a) having damping function is provided. The power electronic system includes power components and a conductor (1a). The conductor (1a) is configured to connect the power components, and includes a damping part (11a) disposed on a surface of the conductor (1a). The damping part (11a) is at least partially formed with a damping material having different resistances at different frequencies, and a relative permeability of the damping material is greater than 1 at a frequency higher than 1MHz. The damping part forms first and second paths for first and second power currents flowing between the power components respectively, the first power current is at a frequency higher than 1MHz, the second power current is at a frequency lower than 1MHz, and a resistance of the first path is higher than a resistance of the second path.