DC Converter Connection Detection via Voltage Comparison

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Solution Overview

Problem

In photovoltaic systems with multiple solar cell strings, determining the correct configuration of DC converters is challenging due to the risk of incorrect manual input, leading to inefficient use of solar cell strings, especially in large systems where hundreds of strings are involved.

Innovation Solution

A method that involves changing the voltage at the connection arrangement of one device and comparing it with another to determine if electrical connections exist between terminal assemblies, allowing for quasi-automated identification of parallel or individual connections of solar cell strings to DC converters, using sensors and a control device to store and manage this information for optimal operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual input is used to configure DC converters, then system setup is simple, but reliability of connection configuration decreases

Engineering Contradiction:
Improvesystem setupVSAvoidconnection configuration
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system automatically determines connection configurations by having DC converters self-test and report their own connection status to the control device, eliminating manual input requirements and preventing configuration errors

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The control device receives automatic feedback from DC converters about their connection status through voltage measurements, enabling reliable configuration determination without manual intervention

Inventive Principle:
Principle #23Feedback

2Productivity

If DC converters are connected in parallel to distribute power, then power distribution efficiency improves, but system complexity increases

Engineering Contradiction:
Improvepower distribution efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system segments the photovoltaic installation into multiple independent DC converters, each handling specific solar cell strings, allowing flexible parallel configuration to optimize power distribution while maintaining manageable system complexity through modular architecture

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If voltage measurement method is used to determine connections, then measurement precision improves, but device complexity increases

Engineering Contradiction:
Improveconnection detection accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

DC converters perform self-testing by measuring their own input voltages and reporting to the control device, achieving precise connection detection without requiring complex external measurement equipment

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The control device uses existing voltage measurement capabilities already present in the DC converters for multiple purposes: both for normal operation control and for connection configuration determination, avoiding additional specialized measurement devices

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

Data Source

PatentEP1891723B1Method for determining the type of connection of at least two electrical devices and system comprising several electric devices
Publication Date: 2018.11.21 SMA SOLAR TECH AG
  • EP1891723B1 patent drawingFigure 1~2
  • EP1891723B1 patent drawingFigure 3
  • EP1891723B1 patent drawingFigure 4~5

AI summary

The invention relates to a method for determining the type of connection of at least two electric devices (5) whereby each device comprises a similar connection arrangement. The aim of the invention is to increase the reliability during the starting up process and during the operation of a system which comprises several electric units (5). According to the invention, a first device (5) modifies the voltage on the connection arrangement (11 ) and the modified voltage is determined as a first voltage, such that a second device (5) determines a second voltage on at least the connection arrangement (11 ) and determines whether an electric connection is required or not between the connection arrangements (11) of the devices (5) by comparing the determined comparison of the voltages.