Noise Filter With Segmented Ring Cores and Ground Terminals
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Solution Overview
Problem
Existing noise filters have limitations in their damping characteristics, necessitating the development of a noise filter with enhanced damping capabilities.
Innovation Solution
A noise filter design featuring a series connection of inductor elements with ring-shaped magnetic cores and conductive ground terminals that surround the magnetic cores, providing improved damping characteristics by effectively dissipating common-mode noise into the ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional common-mode choke coils with U-shaped or EE-shaped magnetic cores are used, then the noise filter can be constructed with simple magnetic core structures, but the damping characteristics are insufficient
Solution Approach 1:
The magnetic core is divided into multiple independent ring-shaped cores, each surrounded by its own conductive part. This segmentation allows each core to independently contribute to damping while the overall structure achieves superior damping characteristics compared to conventional single-piece magnetic cores
Solution Approach 2:
The conductive part is nested around the ring-shaped magnetic core, with the conductive part forming a surrounding structure that encloses the magnetic core. This nested configuration enables the conductive part to effectively interact with the magnetic flux while providing the necessary damping effect
2Reliability
If the conductive part of the ground terminal surrounds the magnetic core, then the damping characteristic is improved, but the manufacturing complexity increases
Solution Approach 1:
The conductive part is designed with specific geometric parameters (surrounding the magnetic core) that optimize the damping effect. By carefully controlling the dimensions and configuration of the conductive part relative to the magnetic core, the damping characteristic is enhanced while maintaining manufacturability through standardized design parameters
3Reliability
If multiple inductor elements are connected in series, then the damping characteristic is enhanced, but the device length increases
Solution Approach 1:
Multiple inductor elements are merged into a compact series connection where the conductive parts and magnetic cores are closely integrated. This merging reduces the overall length compared to separate discrete components while maintaining the enhanced damping characteristic achieved through the series connection
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 noise filter achieves high damping characteristics, reducing common-mode noise across a wide frequency range while minimizing leak current, making it suitable for use in medical instruments and other applications.
Implementation Method 1
a ground terminal disposed between the magnetic core and the winding, the ground terminal being connected to a ground
Implementation Method 2
a ring-shaped magnetic core; a winding wound around the magnetic core
Data Source
AI summary
A noise filter includes a plurality of inductor elements connected with one another in series. The inductor element includes a ring-shaped magnetic core, a winding wound around the magnetic core, and a ground terminal disposed between the magnetic core and the winding, the ground terminal being connected to a ground. The ground terminal includes a conductive part that surrounds at least a part of an outer periphery of the magnetic core.