Vehicle Electrical System DC-Isolation Coupling

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Solution Overview

Problem

Conventional on-board motor vehicle electrical systems face challenges in ensuring standard-conforming DC-isolation between low-voltage and high-voltage supply systems, leading to a risk of short circuits and inaccurate load control.

Innovation Solution

Incorporating a coupling element for signal-transmission between the voltage supply systems, along with a control apparatus and additional control apparatus connected to the coupling element, which uses measurement data from a measuring arrangement to accurately drive loads while maintaining isolation through DC-isolation amplifiers or converters, ensuring safe and effective operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If DC-isolation is implemented between the first voltage supply system and the second voltage supply system, then the risk of short circuit damage is reduced, but the complexity of the system increases due to the need for coupling elements and isolation components

Engineering Contradiction:
Improveprotection against short circuit damageVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A coupling element is introduced as an intermediary between the first voltage supply system (low voltage) and the second voltage supply system (high voltage). This coupling element enables controlled signal transmission and power transfer while maintaining DC-isolation, thereby protecting against short circuit damage without requiring complete electrical separation that would overly complicate the system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the first voltage supply system controls loads in the second voltage supply system through signal transmission, then accurate load control is achieved, but ensuring standard-conforming DC-isolation becomes difficult

Engineering Contradiction:
Improveload control accuracyVSAvoidDC-isolation compliance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The coupling element serves as a mediator that enables accurate control signals to be transmitted from the control apparatus in the first voltage supply system to the switching element in the second voltage supply system, while simultaneously maintaining standard-conforming DC-isolation between the two systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct electrical connection with a coupling element that uses alternative physical principles (such as electromagnetic coupling or optical isolation) to transmit control signals without direct electrical contact, thereby achieving both accurate control and reliable DC-isolation.

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

3Productivity

If the control apparatus is connected to the second voltage supply system for load control, then accurate driving of loads is enabled, but the risk of short circuits increases due to potential isolation failures

Engineering Contradiction:
Improveload driving accuracyVSAvoidshort circuit risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The coupling element acts as a protective intermediary between the control apparatus and the second voltage supply system, enabling accurate load control while preventing harmful short circuits from propagating between the isolated voltage systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The DC-isolation provided by the coupling element serves as a preventive protective measure, cushioning the system against potential short circuit damage before such failures can occur, allowing the control apparatus to safely control high-power loads.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP3403885B1On-board motor vehicle electrical system
Publication Date: 2019.11.20 MAHLE INT GMBH
  • EP3403885B1 patent drawingFigure 1~2
  • EP3403885B1 patent drawingFigure 3~4

AI summary

The invention relates to an on-board motor vehicle electrical system (1) comprising a first voltage supply system (2a) and comprising a second voltage supply system (2b). The first voltage supply system (2a) has a first voltage source with a relatively low voltage, and the second voltage supply system (2b) has a second voltage source with a relatively high voltage. Furthermore, the first voltage supply system (2a) and the second voltage supply system (2b) are DC-isolated from one another and connected to one another in a signal-transmitting manner by a coupling element (3). The second voltage supply system (2a) has at least one electrical switching element (4) for a load (5), and the on-board motor vehicle electrical system (1) has a control apparatus (6) for controlling the load (5) by means of the respective switching element (4). According to the invention, the coupling element (3) is connected to the respective switching element (4) in a signal-transmitting manner by means of the control apparatus (6).