Multi-Voltage Control Device for Motor Vehicle Ground Interruption
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Solution Overview
Problem
In motor vehicles with multi-voltage electrical systems, potential separation is necessary to prevent feedback of higher supply voltage into lower voltage systems, but this requires separate grounding, which is costly and complex, and existing solutions do not effectively address interruptions between the ground terminal and ground potential.
Innovation Solution
A control device with a switching device that interrupts current flow based on a voltage signal indicating a potential difference between the ground terminal and the ground potential, allowing a common ground connection and eliminating the need for separate grounding, using a MOSFET transistor and control transistor to quickly switch off electrical loads in case of an interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If potential separation is implemented to prevent feedback of higher supply voltage into lower voltage systems, then system safety is improved, but device complexity and grounding requirements worsen
Solution Approach 1:
The patent introduces a potential separation unit as an intermediary component between the first electrical system (higher voltage) and the second electrical system (lower voltage). This unit includes a first potential separation circuit and a second potential separation circuit that are electrically connected through a galvanically isolated interface, allowing voltage feedback prevention while maintaining a common ground connection. The intermediary structure enables safe voltage isolation without requiring separate grounding systems.
Solution Approach 2:
The control device is segmented into multiple functional circuits: a first control circuit for the first electrical system, a second control circuit for the second electrical system, and a potential separation unit connecting them. Each circuit can be independently grounded to the common ground potential, eliminating the need for separate grounding systems while maintaining electrical isolation between voltage domains.
2Reliability
If separate grounding is implemented for each electrical system, then feedback prevention is improved, but manufacturing cost and installation complexity worsen
Solution Approach 1:
The patent merges the grounding systems of the first and second electrical systems into a single common ground potential. The potential separation unit enables both systems to share this common ground while preventing voltage feedback through galvanic isolation. This consolidation reduces the number of ground terminals and cabling requirements, lowering manufacturing costs and installation complexity compared to separate grounding systems.
3Ease of operation
If a common ground connection is used for both electrical systems, then installation complexity is reduced, but voltage feedback risk increases
Solution Approach 1:
The potential separation unit acts as a mediator between the first and second control circuits that share a common ground connection. It includes galvanically isolated interfaces that prevent direct electrical connection between the higher voltage first electrical system and the lower voltage second electrical system, thereby eliminating voltage feedback risk while allowing both systems to use the same ground potential.
Solution Approach 2:
The patent implements preliminary protective measures by incorporating the potential separation unit before voltage feedback can occur. The first and second potential separation circuits are designed to block reverse voltage flow from the higher voltage system to the lower voltage system, preventing harmful effects before they can manifest in the shared ground 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
This solution prevents feedback of higher supply voltage into lower voltage systems without the need for potential separation or dual cabling, ensuring safe and efficient operation by quickly isolating electrical loads in case of ground interruptions, reducing the risk of damage and operational complexity.
Implementation Method 1
The control device has a switching device connected downstream of the first connection, which is configured to interrupt or block current flow through the first connection depending on a voltage signal
Implementation Method 2
A control device with a switching device that interrupts current flow based on a voltage signal indicating a potential difference between the ground terminal and the ground potential
Data Source
AI summary
The disclosure relates to a control device for a motor vehicle which comprises a first electrical terminal for receiving a first supply voltage of a first vehicle electrical system and a second electrical terminal for receiving a second supply voltage of a second vehicle electrical system, the second supply voltage being smaller than the first supply voltage, wherein an electrical ground terminal is provided for closing a common ground potential of the first and second vehicle electrical systems, and a switching device connected downstream of the first terminal is set up, depending on a voltage signal which is determined by a potential difference between the second terminal and the ground terminal, to block a current flow through the first terminal, wherein the switching device interrupts the current flow if the voltage signal indicates an interruption of an electrical connection between the ground terminal and the ground potential.