Vehicle Low-Voltage Network Insulation Checking via DC/DC Converters

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Solution Overview

Problem

Existing technologies face challenges in effectively checking and ensuring the insulation between low-voltage networks of a vehicle, which is crucial for the safety and reliability of automated driving systems.

Innovation Solution

A method and low-voltage supply arrangement that utilize DC/DC converters to induce a voltage change on one low-voltage network, detect and evaluate the voltage on other networks, and derive a checking decision to determine the integrity of insulation between networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate insulation monitoring devices are connected to each low-voltage network, then insulation monitoring capability is improved, but device complexity and cost increase

Engineering Contradiction:

Improveinsulation monitoring capabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the insulation monitoring function with the DC/DC converter by integrating a monitoring unit into the converter's control device. This allows the DC/DC converter to actively impress voltage changes and monitor the resulting voltage responses across multiple low-voltage networks, eliminating the need for separate insulation monitoring devices while maintaining comprehensive monitoring capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The DC/DC converter is designed to perform multiple functions: power conversion from high-voltage to low-voltage, and insulation monitoring across multiple low-voltage networks. The control device of the DC/DC converter executes both power management and insulation monitoring tasks, making the converter a universal component that serves dual purposes and reduces overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If additional monitoring components are added to each network, then measurement precision is improved, but ease of manufacture deteriorates

Engineering Contradiction:

Improvevoltage detection precisionVSAvoidease of manufacture

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The monitoring function is merged into the existing DC/DC converter structure, utilizing the converter's control device and voltage sensing capabilities for insulation monitoring. This integration approach maintains precise voltage detection across multiple networks while avoiding the need for additional monitoring components, thereby simplifying the manufacturing process and reducing assembly complexity.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If multiple separate monitoring systems are used, then reliability is improved, but loss of time in inspection increases

Engineering Contradiction:

Improveinsulation check reliabilityVSAvoidinspection time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The control device of the DC/DC converter periodically impresses voltage changes on the low-voltage networks and measures the resulting voltage responses to detect insulation faults. This periodic active monitoring approach enables comprehensive insulation checking across multiple networks in a systematic manner, maintaining high reliability while minimizing inspection time through efficient sequential measurement.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The monitoring system continuously measures voltage responses and provides feedback to the control device, which evaluates the measurements to detect insulation faults. This feedback mechanism enables real-time insulation monitoring across multiple low-voltage networks, ensuring high reliability while allowing for prompt fault detection without requiring extensive inspection time.

Inventive Principle:

Principle #23Feedback

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 allows for regular, cost-effective insulation checks without additional components, enhancing the availability and safety of the vehicle's low-voltage supply system by promptly detecting insulation faults.

Implementation Method 1

Each of the low-voltage networks comprises a DC/DC converter, an energy storage device and a supply bus

Methodology Applied

Scientific EffectElectrical energy transformation:

Implementation Method 2

detecting a respective voltage on the supply buses of at least the other low-voltage networks; evaluating the detected voltages

Methodology Applied

Scientific EffectVoltage detection:

Data Source

PatentUS20250164542A1Method for checking insulation between low-voltage networks of a vehicle, and low-voltage supply arrangement for a vehicle

Publication Date: 2025.05.22 VOLKSWAGEN AG

AI summary

Technologies and techniques for checking insulation between low-voltage networks of a vehicle, wherein the low-voltage networks are galvanically separated and each comprise a DC/DC converter, an energy storage device, and a supply bus for supplying low-voltage consumers. The DC/DC converter is connected on one side to a high-voltage supply and on the other side to the energy storage device and the supply bus. The method includes: applying a voltage change to the high-voltage supply or the supply bus of one of the low-voltage networks using the DC/DC converter of said low-voltage network; detecting a voltage on each of the supply buses of at least the other low-voltage networks; evaluating the detected voltages; and deriving and outputting a test decision. A corresponding low-voltage supply arrangement is also disclosed.