Redundant Vehicle Power Supply Switchover for Fault-Tolerant Loads
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Solution Overview
Problem
Existing energy supply systems for vehicles with safety-related loads, such as those for highly automated driving and x-by-wire systems, face challenges in achieving the required availability and redundancy to prevent single-point failures, especially in asymmetrical redundancy configurations, where the failure of a high-performance subsystem significantly impairs system performance.
Innovation Solution
A device with asymmetrical redundancy that employs two separate energy supply units connected via switch elements and delimitation elements, including resistors and filters, to ensure uninterrupted energy supply to the load, with a control unit managing the switchover between supply units based on voltage thresholds to maintain system availability and prevent common cause failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If asymmetrical redundancy is implemented with a high-performance subsystem, then system performance is improved, but the probability of failure increases significantly when the high-performance subsystem fails
Solution Approach 1:
The energy supply system is segmented into multiple independent supply units (first energy supply unit and second energy supply unit), each capable of independently supplying power to the subsystems. This segmentation allows the system to maintain reliability by isolating failures to individual units while preserving overall system functionality.
Solution Approach 2:
The system implements beforehand cushioning by providing redundant energy supply units and switch elements that can activate in advance or immediately upon detection of a failure. The control unit monitors the health of supply units and pre-configures backup paths, ensuring that when a high-performance subsystem fails, the redundant units are already positioned to take over, thereby cushioning the impact on system reliability.
2Reliability
If three independent supply units are employed to achieve fault-tolerant system with single failure tolerance, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the functionality of multiple supply units by allowing them to operate in parallel and be selectively activated. The switch elements enable the system to combine or separate supply paths dynamically, achieving fault tolerance with two supply units rather than requiring three independent units. This merging approach reduces device complexity while maintaining the required reliability level.
Solution Approach 2:
Each energy supply unit is designed with universal functionality to supply power to any subsystem (first subsystem or second subsystem) as needed. The switch elements and control unit enable any supply unit to serve any load, creating a multi-functional system where two units can provide the same fault tolerance as three dedicated units would, thereby reducing overall system complexity.
3Reliability
If redundant energy supply units are implemented, then availability is improved, but system complexity and cost increase
Solution Approach 1:
The system implements dynamics by enabling real-time switching between redundant energy supply units based on their operational status. The control unit dynamically monitors the health of supply units and automatically reconfigures the system topology using switch elements, allowing the redundancy architecture to adapt its complexity only when needed. This dynamic approach maintains high availability while minimizing the operational complexity of the redundant system.
Data Source
AI summary
A device includes a first supply unit, which is connectable via a first switch element to a first consumer, a second supply unit, which is connectable via a second switch element and via one or more electric delimitation elements to the first consumer, and a third switch element, which is configured to bridge the one or more electric delimitation elements. A control unit is configured to cause the first switch element to close, and the second and third switch elements to open, in normal operation. The control unit is further configured to detect that a first supply voltage at the first supply unit has reached or fallen below a voltage threshold value, and in response causes first the second switch element to close, then the first switch element to open, and then the third switch element to close, such that the first consumer is coupled to the second supply unit.