High-Voltage Vehicle Measuring Device Using Optocoupler Isolation

Solution Overview

Problem

Existing measuring devices for high-voltage vehicle electrical systems are susceptible to capacitive interference, which affects their accuracy in determining the operating state of test sections such as switches and fuses.

Innovation Solution

A measuring device that couples a test voltage signal into an electrical high-voltage conductor and detects its presence or absence at a receiving device, using optocouplers for isolation and minimizing interference, allowing for reliable detection of the test section's conductive or non-conductive state regardless of capacitive influences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional measuring devices are used to detect the operating state of test sections, then the measuring devices can provide basic detection capability, but capacitive interference significantly degrades measurement precision

Engineering Contradiction:

Improvedetection accuracy of test section stateVSAvoidcapacitive interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary test voltage signal that is coupled into the high-voltage conductor through a sending device and detected by a receiving device. This intermediary signal acts as a carrier that is modulated by the test section state, allowing detection without direct contact with the high-voltage conductor, thereby eliminating capacitive interference while maintaining measurement precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces conventional direct electrical contact measurement with an optical isolation approach using optocouplers. The sending device converts electrical test signals to optical signals that pass through the isolation barrier, and the receiving device converts them back to electrical signals. This substitution eliminates capacitive coupling between the measurement circuit and the high-voltage conductor, resolving the interference issue.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If direct electrical contact measurement is used, then simple detection is possible, but the measuring device is vulnerable to high-voltage interference and capacitive effects

Engineering Contradiction:

Improvemeasurement system simplicityVSAvoidimmunity to capacitive interference

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces an intermediary test voltage signal that is coupled into the high-voltage conductor through a sending device and detected by a receiving device. This intermediary signal acts as a carrier that is modulated by the test section state, allowing detection without direct contact with the high-voltage conductor, thereby eliminating capacitive interference while maintaining measurement precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces conventional direct electrical contact measurement with an optical isolation approach using optocouplers. The sending device converts electrical test signals to optical signals that pass through the isolation barrier, and the receiving device converts them back to electrical signals. This substitution eliminates capacitive coupling between the measurement circuit and the high-voltage conductor, resolving the interference issue.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If high-power test signals are used to ensure detection, then signal detection reliability is improved, but energy consumption and interference with normal system operation increase

Engineering Contradiction:

Improvesignal detection reliabilityVSAvoidtest signal power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic pulse-width modulated test signals instead of continuous high-power signals. The sending device generates periodic test pulses that are coupled into the conductor only during measurement intervals, and the receiving device detects these periodic signals. This periodic action ensures reliable detection while minimizing energy consumption and avoiding continuous interference with normal system operation.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent uses low-power test signals that are sufficient for detection purposes but well below the power level of normal system operation. By applying only the minimum necessary signal strength (partial action) required to detect the test section state, the system achieves reliable detection without excessive energy consumption or interference with the high-voltage conductor's normal function.

Inventive Principle:

Principle #16Partial or excessive action

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 provides a reliable and interference-resistant method for determining the state of test sections, including switches and fuses, even during no-load operations, by using a low-power, digital pulse width-modulated test voltage signal that is immune to capacitive interference.

Implementation Method 1

a sending device assigned to an electrical high-voltage conductor (4) of a high-voltage vehicle electrical system (3), in particular a 5 volt to 1000 volt direct high-voltage vehicle electrical system or particularly a 48 volt direct high-voltage vehicle electrical system, which during its operation provide a test voltage signal (6) and can couple the same into this electrical high-voltage conductor (4)

Methodology Applied

Scientific EffectElectrical signal transmission: Conduction (electrical)

Implementation Method 2

a receiving device assigned to the electrical high-voltage conductor (4), which can detect the test voltage signal (6) coupled into the electrical high-voltage conductor (4)

Methodology Applied

Scientific EffectElectrical signal detection: Conduction (electrical)

Implementation Method 3

using optocouplers for isolation and minimizing interference

Methodology Applied

Scientific EffectOptical isolation:

Data Source

PatentEP4086644A1Measuring device and diagnostic method for a high-voltage vehicle electrical system

Publication Date: 2022.11.09 MAHLE INT GMBH

Figure 1~2

AI summary

The present invention relates to a measuring device (1) for a test section (2) of a high-voltage vehicle electrical system (3) arranged in a vehicle, comprising: a sending device (5) assigned to an electrical high-voltage conductor (4) of a high-voltage vehicle electrical system (3), which provides a test voltage signal (6) and couples the same into the electrical high-voltage conductor (4), a receiving device (7) assigned to the electrical high-voltage conductor (4), which can detect as measuring signal the coupled-in test voltage signal (6). The invention, furthermore, relates to a diagnostic method for determining an operating state of a test section (2) of an electrical high-voltage conductor (4) with a measuring device (1). The invention, furthermore, relates to a use of such a measuring device (1).