Flat Conductor Rail Ground Return for Vehicle EMC
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Solution Overview
Problem
Existing vehicle energy supply systems face challenges with undefined ground return currents due to varying material combinations and joining techniques, leading to electromagnetic compatibility (EMC) issues and inefficient power distribution, especially in vehicles with nonconductive bodies like carbon-fiber-reinforced plastic (CFRP).
Innovation Solution
An electrical energy supply system featuring a stable, easily installable flat conductor rail ground conductor made of aluminum or aluminum alloy, integrated into the vehicle's body in white before attachments, which provides a clear and predictable ground return path, decoupled from supply lines to improve EMC by canceling out electromagnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ground return is achieved via the electrically conductive body of the vehicle, then a simple ground return path is provided, but this approach fails when the body is made from material combinations with low electrical conductivity such as CFRP
Solution Approach 1:
The ground return system is segmented into modular ground conductors that can be independently installed on different body sections. These conductors are designed as separate components that can be adapted to various body materials including CFRP, allowing the system to maintain functionality across different vehicle configurations without requiring a completely different ground return approach for each material type.
Solution Approach 2:
Ground conductors serve as intermediary elements between the electrical systems and the vehicle body. Rather than relying directly on the body's electrical conductivity, these conductors mediate the ground return path, enabling reliable electrical connection even when the body material (such as CFRP) has low conductivity. The conductors can be integrated with or mounted near the body structure to provide the necessary electrical pathway.
2Adaptability or versatility
If individual leads are routed through the vehicle to distributed electrical loads, then power distribution to multiple loads is achieved, but the installation becomes complex and time-consuming
Solution Approach 1:
Multiple ground conductors are merged into a coordinated system that works together to serve multiple electrical loads. Rather than routing individual leads separately to each load, the conductors are integrated into a unified ground return network that can serve multiple points simultaneously, reducing installation complexity while maintaining the ability to distribute power to distributed loads.
Solution Approach 2:
The ground conductor system is designed with multi-functionality to serve both as ground return paths and as structural or organizational elements within the vehicle. The conductors can be configured to serve multiple electrical loads simultaneously and can be adapted to different vehicle layouts, reducing the need for complex individual routing while maintaining versatility in power distribution.
3Ease of operation
If ground return current follows the path of least electrical resistance through the vehicle body, then automatic current distribution is achieved, but the ground return path becomes undefined and unpredictable with different material combinations
Solution Approach 1:
Ground conductors are installed in predetermined positions and configurations before final vehicle assembly. This preliminary placement ensures that the ground return paths are defined and controlled from the outset, rather than relying on unpredictable current paths through heterogeneous body materials. The conductors are positioned to optimize electrical connectivity and EMC performance before other vehicle components are added.
Solution Approach 2:
The system replaces reliance on the mechanical/structural body materials for electrical conduction with dedicated electrical conductors. Instead of depending on the electrical properties of body materials (steel, aluminum, CFRP composites), the ground return function is substituted with purpose-built conductive elements that provide predictable and controlled current paths regardless of the body material composition.
4Area of stationary object
If supply lines are routed close to the ground conductor to save space, then installation space is optimized, but electromagnetic fields cause EMC problems
Solution Approach 1:
The spatial relationship between supply lines and ground conductors is optimized locally rather than requiring uniform spacing throughout. Ground conductors are positioned to provide adequate electromagnetic shielding in critical areas where supply lines pass nearby, while allowing closer proximity in areas where electromagnetic interference is less critical. This local optimization maintains space efficiency while protecting against EMC issues in sensitive regions.
Solution Approach 2:
The ground conductor, which could be considered a source of electromagnetic interference when carrying return currents, is positioned and configured to actually reduce overall EMC issues. By providing a controlled, low-impedance ground path, the conductor stabilizes voltage references and reduces electromagnetic radiation from nearby supply lines, converting what could be a harmful element into a protective one for the overall system's electromagnetic compatibility.
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 enables simple and effective ground return even in vehicles with nonconductive materials, enhancing EMC properties and allowing for flexible design and installation, supporting both low and high voltage systems, while reducing the need for additional shielding.
Implementation Method 1
decoupled from supply lines to improve EMC by canceling out electromagnetic fields
Data Source
AI summary
An electrical energy supply system for a vehicle includes at least one ground conductor configured as a flat conductor rail arranged on a floor assembly of a body in white of the vehicle. At least one supply line inserted into the body in white is included and the at least one supply line is guided, at least one section of the body in white, parallel to and along the at least one ground conductor such that the at least one supply line at least partially overlaps a flat side of the at least one ground conductor. The body in white is made from a metallic material, the at least one supply line is positioned a predetermined distance from the at least one ground conductor, and the predetermined distance is a function of an electromagnetic field resulting from a current flowing through the at least one supply line.