Vehicle Power Supply Isolation for Autonomous Driving Failover

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Solution Overview

Problem

Existing autonomous driving systems face reliability issues due to the interconnectedness of power supply systems, where a failure in the autonomous driving system's power supply can compromise the vehicle platform's power supply, leading to potential safety hazards.

Innovation Solution

The implementation of an independent power supply structure for the autonomous driving system and the vehicle platform, with redundant secondary power systems in both, allowing the vehicle platform to maintain critical functions like steering and braking even if the primary power supply fails, using switching DC/DC converters for rapid disconnection and maintaining power for a limited time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the autonomous driving system shares the power supply structure with the vehicle platform, then the device complexity is reduced, but the reliability of the vehicle platform's power supply deteriorates when the autonomous driving system experiences power supply failures

Engineering Contradiction:
Improvepower supply structure complexityVSAvoidvehicle platform power supply reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The power supply system is segmented into independent domains: the vehicle platform power supply system (comprising high-voltage battery 150, DC/DC converter 152, and auxiliary battery 154) and the autonomous driving system power supply system (comprising high-voltage battery 242, DC/DC converter 244, and auxiliary battery 244). This segmentation isolates failure modes, ensuring that power supply failures in the autonomous driving system do not propagate to the vehicle platform, thereby resolving the reliability issue while maintaining manageable complexity through modular architecture.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a redundant secondary power supply system is added to the autonomous driving system, then the reliability of the autonomous driving system improves, but the device complexity increases

Engineering Contradiction:
Improveautonomous driving system power supply reliabilityVSAvoidpower supply system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The redundant power supply is implemented as a separate, independent system with its own high-voltage battery 242, DC/DC converter 244, and auxiliary battery 244. This segmentation allows the autonomous driving system to have dual power supply paths without complicating the vehicle platform's power supply architecture. The independent redundancy provides reliability benefits while containing complexity within the autonomous driving system domain.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The vehicle control interface box 110 acts as an intermediary between the two independent power supply systems. It manages power distribution and coordination between the vehicle platform and autonomous driving system, enabling the redundant power supply to function effectively without directly increasing the complexity of either system's core architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Duration of action of moving object

If the secondary power supply system is used to maintain power during primary power supply failure, then the duration of critical system operation is extended, but the device complexity increases due to switching mechanisms

Engineering Contradiction:
Improvecritical system operation durationVSAvoidpower switching mechanism complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The secondary power supply system (high-voltage battery 242, DC/DC converter 244, auxiliary battery 244) is pre-configured and ready to activate immediately upon detection of primary power supply failure. The switching DC/DC converter 156 is designed to rapidly disconnect the primary power supply and connect the secondary power supply without requiring complex real-time decision-making circuits. This preliminary configuration extends critical system operation duration while minimizing switching mechanism complexity through pre-established failover paths.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces mechanical relay-based switching with electronic switching DC/DC converters (156 and 246) that can rapidly transition between power sources. This substitution reduces mechanical complexity and improves switching speed, enabling the secondary power supply to take over seamlessly during primary power supply failure, thereby extending operational duration with minimal added complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Ensures the reliability of the vehicle platform's power supply by isolating it from autonomous driving system failures, ensuring continued operation of critical systems like steering and braking, and maintaining power for a defined period through redundant power sources.

Implementation Method 1

a switching DC/DC converter that electrically disconnects the secondary battery from the primary power supply system

Methodology Applied
Scientific EffectElectrical disconnection through switching device: Relay

Data Source

PatentEP3858654B1vehicle
Publication Date: 2025.01.01 TOYOTA JIDOSHA KK
  • EP3858654B1 patent drawingFigure 1
  • EP3858654B1 patent drawingFigure 2
  • EP3858654B1 patent drawingFigure 3

AI summary

A vehicle (10) includes an ADK (200) that creates a driving plan, a VP (120) that carries out vehicle control in accordance with various commands from the ADK (200), and a vehicle control interface (110) that interfaces between the VP (120) and the ADK (200). A power supply structure for the ADK (200) is provided independently of a power supply structure for the VP (120).