Vehicle Drive Assembly Shielding Frame for EMI Reduction
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Solution Overview
Problem
Existing electric drive assemblies in vehicles emit significant electromagnetic radiation, which can interfere with electronic devices nearby, and existing solutions do not adequately address this issue.
Innovation Solution
A drive assembly with a shielding frame made of electrically conductive material, such as copper or aluminum, is placed between the converter and electric machine housings, forming a Faraday cage to distribute and compensate for emitted electromagnetic waves, and features elastic elements for improved contact and tolerance balancing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductor bars extend through housing gaps between converter and machine housings, then electrical connection is achieved, but electromagnetic radiation increases
Solution Approach 1:
A shielding frame made of electrically conductive material is introduced as an intermediary element between the converter housing and machine housing. This shielding frame encloses the conductor bars and forms a Faraday cage structure, mediating between the electrical connection requirement and electromagnetic radiation reduction by providing both electrical continuity and electromagnetic shielding.
Solution Approach 2:
The shielding frame changes the electromagnetic field distribution parameters by creating a conductive enclosure around the conductor bars. This alters the electromagnetic radiation characteristics by redistributing the electromagnetic fields through the conductive shielding structure, reducing harmful radiation while maintaining electrical functionality.
2Object-generated harmful factors
If shielding components are added to reduce electromagnetic radiation, then electromagnetic shielding improves, but device complexity increases
Solution Approach 1:
The shielding frame is designed as a thin-walled, cage-like structure that provides effective electromagnetic shielding without adding substantial complexity or volume. The frame format with enclosed conductor bars creates a Faraday cage using minimal material, achieving radiation reduction while maintaining structural simplicity and ease of integration.
3Object-generated harmful factors
If housing gap is reduced to minimize radiation, then electromagnetic shielding improves, but manufacturing precision requirements increase
Solution Approach 1:
The shielding function is extracted from the housing structure itself and implemented as a separate, dedicated shielding frame component. This allows the shielding functionality to be achieved without requiring tight tolerances in housing manufacturing or assembly, as the shielding frame independently provides the electromagnetic protection regardless of housing gap variations.
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 shielding frame effectively reduces electromagnetic radiation emission, is easy to mount and replace, and ensures reliable electrical and mechanical contact between the housings, enhancing the shielding effectiveness.
Implementation Method 1
The shielding frame is a closed frame that defines a frame opening through which the busbars or conductor bars project. The shielding frame is in mechanical contact with both the machine housing and the converter housing, which can both likewise be made of an electrically conductive material. This creates a type of Faraday cage around the conductor bars.
Implementation Method 2
Electromagnetic waves emitted by the conductor bars can thus be distributed by the shielding frame or induce an oppositely directed electrical field in the shielding frame, which at least partially compensates for the emitted electromagnetic waves.
Data Source
AI summary
A drive assembly for a vehicle includes a converter having a converter housing and an electric converter circuit disposed in the converter housing, an electric machine having a machine housing disposed adjacent to the converter housing and a stator/rotor arrangement disposed in the machine housing, a plurality of conductor bars which electrically connect the converter circuit and the stator/rotor arrangement and extend through first passage openings formed in the converter housing and through second passage openings formed in the machine housing, and a shielding frame which is made of an electrically conductive material, is disposed between the converter housing and the machine housing, encloses the plurality of conductor bars and abuts the converter housing and the machine housing.