Potential-Isolated Power Supply Monitoring with Single Optocoupler

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Solution Overview

Problem

Existing power supply arrangements in rail vehicle technology require reliable voltage monitoring with minimal component usage, especially when multiple output voltages need to be checked for reaching a minimum voltage, and existing solutions often require individual feedback paths for each output, which is inefficient.

Innovation Solution

A monitoring device connected to multiple outputs of an electrically isolated power supply generates a current when all output voltages reach their minimum, using a single optocoupler for feedback, with controlled current sources and comparators ensuring each output voltage is monitored, and resistors connected to the optocoupler input to indicate the status of output voltages, allowing for easy determination of which voltages have reached their minimum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If individual feedback paths or optocouplers are provided for each output voltage, then monitoring reliability is improved, but device complexity and component quantity increase

Engineering Contradiction:
Improvevoltage monitoring reliabilityVSAvoidfeedback path complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple individual feedback paths and optocouplers are merged into a single shared feedback path with one optocoupler. The monitoring device combines status information from all output voltages into a single feedback signal that is transmitted through the optocoupler to the control device, reducing component quantity while maintaining monitoring capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single optocoupler and feedback path are designed to handle multiple functions simultaneously - monitoring status of all output voltages, transmitting combined status information, and enabling centralized control. The monitoring device acts as a multi-functional unit that consolidates what would otherwise require separate dedicated paths for each output.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If multiple individual monitoring devices are used for each output, then measurement precision is improved, but manufacturing cost and component usage increase

Engineering Contradiction:
Improveoutput voltage monitoring precisionVSAvoidmanufacturing simplicity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

Multiple individual monitoring devices are merged into a single integrated monitoring device that monitors all output voltages simultaneously. The device includes multiple voltage-dividing resistor networks for precise measurement of each output, combined with a control unit that processes all measurements and generates appropriate control signals through the single optocoupler.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single monitoring device is designed with multi-functional capability to monitor multiple output voltages, perform individual precision measurements using separate resistor networks for each output, process all measurements centrally, and generate controlled output signals. This universal design achieves the precision of multiple devices while simplifying manufacturing.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If a single optocoupler is used for feedback, then device complexity is reduced, but difficulty of detecting and measuring individual output status increases

Engineering Contradiction:
Improvefeedback path complexityVSAvoidindividual output status detection
Core Design Contradiction:
Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

The monitoring function is segmented into separate voltage-dividing resistor networks for each output voltage, allowing individual measurement of each output status. Each resistor network is connected to the control unit through distinct pathways, enabling the control unit to individually detect and measure the status of each output voltage even though the final feedback signal uses a single optocoupler.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control unit acts as an intermediary between the multiple output voltages and the single optocoupler. It receives individual voltage status information from each output through separate measurement circuits, processes this information, and generates the appropriate combined feedback signal for the optocoupler. This intermediary function preserves individual output detectability while enabling single-optocoupler implementation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 reliable and efficient monitoring of output voltages using a single optocoupler, reducing component usage and enabling easy determination of which output voltages have reached their minimum, with the ability to calibrate the monitoring system for accurate feedback.

Implementation Method 1

an optocoupler (40), the optocoupler output of which is connected to a control device (50) located electrically on the input side of the arrangement

Methodology Applied
Scientific EffectOptical coupling: Photoelectric Effect

Data Source

PatentEP3039779B1Assembly having a potential-isolated power supply device
Publication Date: 2017.11.01 SIEMENS AG
  • EP3039779B1 patent drawingFigure 1
  • EP3039779B1 patent drawingFigure 2
  • EP3039779B1 patent drawingFigure 3

AI summary

The invention relates to an assembly (10), comprising an input side (11), an output side (12) isolated from the input side (11) in respect of electrical potential, and a potential-isolated power supply device (20), which has: an input (E20) on the input side (11) of the assembly for applying an input voltage (Ue) and at least two outputs (A21, A22, A23) on the output side (12) of the assembly for outputting at least two output voltages (Ua1, Ua2, Ua3), which outputs are isolated from the input (E20) in respect of potential. According to the invention, a monitoring device (30) is connected to the at least two outputs (A21, A22, A23) of the potential-isolated power supply device (20), which monitoring device monitors the output voltages (Ua1, Ua2, Ua3) for the attainment of respective minimum voltages (Umin1, Umin2, Umin3) associated individually with the outputs and produces a current (Is) having a desired level on the output side if all output voltages (Ua1, Ua2, Ua3) attain their respective minimum voltages (Umin1, Umin2, Umin3) associated individually with the respective outputs, to which monitoring device (30) an optocoupler input (E40) of an optocoupler (40) is connected, an optocoupler output (A40) of which is connected to a control device (50) located electrically on the input side (11) of the assembly (10), and the control device (50) generates an fault signal (Sf) if an output signal (Sa) that deviates beyond a specified extent from the desired output signal occurring in the event of a current having said desired level is present at the optocoupler output (A40).