On-Board Power Switch Topology for Equalizing Current Isolation
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Solution Overview
Problem
Automated and autonomous driving systems face safety issues due to voltage dips in vehicle on-board power supplies, which can cause malfunctions in safety-relevant loads despite redundant power systems, as equalizing currents can lead to voltage drops in connected loads.
Innovation Solution
A vehicle on-board electrical network switch with semiconductor switches and body diodes that isolate power supplies during faults, allowing for fast and stable voltage maintenance by simultaneously opening switches when a voltage dip is detected, preventing equalizing currents and ensuring continuous power supply to safety-relevant loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two on-board power supplies are connected in parallel to supply safety-relevant loads, then redundancy and reliability are improved, but voltage dips can propagate between power supplies through equalizing currents, causing stability issues
Solution Approach 1:
The patent introduces switching elements as intermediaries between the on-board power supplies and the common electrical network. These switches act as mediators that can isolate faulty power supplies from the network, preventing voltage dips from propagating while maintaining the redundant configuration. The switching elements control the connection state between power supplies and the common node, enabling selective isolation when needed.
Solution Approach 2:
The patent implements dynamic switching control where the connection state between power supplies and the common electrical network changes based on operational conditions. The switching elements can transition between connected and isolated states, allowing the system to adapt its configuration dynamically. This dynamic behavior enables the system to maintain stable voltage by isolating faulty supplies while preserving redundancy during normal operation.
2Stability of the object's composition
If switching elements are used to isolate power supplies during voltage dips, then voltage stability for safety-relevant loads is improved, but the device complexity increases due to additional switches and control circuitry
Solution Approach 1:
The patent combines multiple switching elements into a single integrated switching device or module that manages connections for multiple power supplies. The control circuitry is merged with the switching elements to form an integrated power management unit. This merging approach reduces the overall device complexity by consolidating components and simplifying the control architecture while maintaining the necessary isolation functionality.
Solution Approach 2:
The switching elements are designed to perform multiple functions: normal power distribution, fault isolation, and voltage dip prevention. The same switching mechanism serves both routine operational control and emergency protection functions. This multi-functionality reduces the need for separate dedicated components, thereby lowering device complexity while achieving voltage stability.
3Duration of action of stationary object
If the switching element isolates a power supply during a voltage dip, then the duration of voltage dip for safety-relevant loads is reduced, but equalizing currents may still flow through body diodes causing voltage drops
Solution Approach 1:
The patent implements preliminary isolation action where switching elements are designed to open disconnecting faulty power supplies before equalizing currents can significantly impact the electrical network. The switching control is configured to detect voltage dips and initiate isolation rapidly, preventing the development of harmful equalizing currents through body diodes. This preliminary action minimizes the duration and impact of voltage dips by acting preemptively.
Solution Approach 2:
The patent employs rapid switching operation that rushes through the isolation process before equalizing currents can establish significant voltage drops. The switching elements transition quickly from connected to isolated state, skipping the intermediate phase where equalizing currents would flow through body diodes. This rapid action minimizes the time window for harmful current flow, effectively reducing voltage dip duration and preventing equalizing current effects.
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 limits voltage dips to permissible durations, preventing malfunctions in safety-relevant loads by isolating faulty power supplies and maintaining a stable voltage, allowing for quick identification and recovery from faults without interrupting power to essential systems.
Implementation Method 1
The switches can be formed as semiconductor switches and can each be connected with their body diodes in the forward direction towards the common node
Data Source
AI summary
Motor vehicle on-board electrical network switch having at least two inputs for a respective one of at least two on-board power supplies, at least one output for a load of the motor vehicle, at least two switches, a first switch being disposed between a first of the inputs and a common node, and a second switch being disposed between a second of the inputs and the common node, and the output being electrically connected to the common node, wherein the switches are formed as semiconductor switches and are respectively connected with their body diodes in forward direction towards the common node, characterized in that a monitoring circuit monitors a first voltage at the first input and/or a second voltage at the second input and/or a voltage at the common node, and in that the monitoring circuit causes an opening signal for simultaneous opening of both switches depending on an amount of at least one of the monitored voltages.