Dual-Cover EMC Filter Shielding for Leakage and Signal Isolation
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Solution Overview
Problem
Current EMC wave filters in on-board chargers for new energy vehicles suffer from electromagnetic leakage due to inadequate shielding, affecting the operation of peripheral components and external environments, leading to reduced electromagnetic compatibility and stability.
Innovation Solution
An EMC wave-filter shielding structure is proposed, featuring an EMC filter board with a lower and upper shield cover forming a shielding cavity, where capacitors and inductors are arranged within the cavity to enhance electromagnetic shielding, and a connecting holder is used to increase the distance between interference sources and control signals, allowing for flexible installation and reduced size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a barrier isolation apparatus is set up on the housing and main power circuit board, then partial shielding is achieved, but gaps between EMC wave filter apparatus and housing cannot be absolutely covered, resulting in electromagnetic side leakage
Solution Approach 1:
The shielding structure is divided into multiple segments: barrier isolation apparatus on the housing, additional barrier on the main power circuit board, and individual shielding for each EMC wave filter apparatus. This segmented approach allows comprehensive coverage of all potential leakage paths while maintaining modularity and ease of implementation
Solution Approach 2:
Barrier isolation apparatus acts as an intermediary shielding layer between the EMC wave filter apparatus and the housing, while additional barriers serve as intermediaries on the circuit board. These intermediary structures intercept and block electromagnetic waves before they can leak through gaps, thereby improving overall shielding effectiveness
2Volume of moving object
If EMC wave filter apparatus are installed directly on main power circuit board, then space is saved, but electromagnetic leakage strongly influences control signal quality and peripheral apparatuses
Solution Approach 1:
The shielding function is extracted as a separate barrier isolation apparatus that can be independently configured on both the housing and main power circuit board. This allows the EMC wave filter apparatus to remain compactly installed on the circuit board while the extracted shielding barriers provide comprehensive electromagnetic protection without adding significant space
Solution Approach 2:
Barrier isolation apparatus is strategically positioned at specific locations where electromagnetic leakage is most problematic: on the housing surrounding the EMC wave filter apparatus and on the main power circuit board near sensitive control signal areas. This localized shielding approach provides targeted protection where needed most while minimizing overall space consumption
3Object-affected harmful factors
If shielding structure only partially functions as electromagnetic shield inside filter housing, then internal shielding is provided, but external environment and space experience strong electromagnetic leakage and radiation
Solution Approach 1:
The shielding system is segmented into internal shielding (within the filter housing) and external shielding (barrier isolation apparatus on housing and circuit board). This multi-level segmentation ensures that electromagnetic waves are blocked both internally and externally, preventing radiation to the external environment while maintaining compact design
Solution Approach 2:
The barrier isolation apparatus on the housing serves as an intermediary shielding layer between the internal filter housing and the external environment. This intermediary structure intercepts electromagnetic waves that escape from the housing, providing an additional layer of protection against external radiation while maintaining the original internal shielding configuration
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 solution effectively reduces electromagnetic interference, improves control signal quality, and allows for more compact and flexible installation of on-board chargers by enhancing the electromagnetic shielding performance and utilizing space more efficiently.
Implementation Method 1
a lower shield cover installed on one side of the EMC filter board, and connected with the EMC filter board around to form a shielding cavity; an upper shield cover installed on the other side of the EMC filter board backing toward the shielding cavity, and directly opposite to the lower shield cover
Data Source
AI summary
The present invention discloses an EMC wave-filter shielding structure including an EMC filter board; a lower shield cover that is installed on one side of the EMC filter board, and connected with the EMC filter board around to form a shielding cavity; a X capacitor, a Y capacitor, a first filter inductor and a second filter inductor that are all arranged in the shielding cavity and correspondingly connected with the EMC filter board, respectively; and an upper shield cover that is installed on the other side of the EMC filter board backing toward the shielding cavity, and directly opposite to the lower shield cover. The present invention increases the distance between an electromagnetic interference source and a control signal, and enhancing quality of control signals.