Filter Current Monitoring in Power Converters

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Solution Overview

Problem

Existing devices for delivering regeneratively generated electrical power, such as wind turbines, face challenges in accurately monitoring the functioning of filters during operation, leading to potential system failures and increased maintenance costs due to imprecise measurement methods that only allow for filter checking during startup.

Innovation Solution

The implementation of means to continuously determine filter currents using current sensors, enabling monitoring of filter performance in real-time, regardless of the filter's connection topology, and allowing for early detection of aging or deviations from specifications, thereby facilitating proactive maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If measuring sensors designed for high output power are used to monitor filter functionality, then the system can verify filter function during startup, but the measurement precision is insufficient because the sensors are 10 to 100 times more sensitive than needed for filter current measurement

Engineering Contradiction:
Improvefilter functionality verificationVSAvoidfilter current measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent segments the measurement function by introducing a separate measurement channel with dedicated measurement sensors that are specifically designed for filter current ranges. This separates the high-power output measurement (handled by existing sensors) from the low-power filter current measurement (handled by new dedicated sensors), allowing each to be optimized for its specific range without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary measurement system that bridges the gap between the high-power output sensors and the low-power filter currents. The new measurement sensors act as intermediaries specifically calibrated for filter current ranges, providing accurate measurements that would be impossible with the existing high-power sensors alone.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If filters are only checked during system startup, then the existing measurement system can be used, but filter defects may only be detected during the next startup, posing a risk of damage or reduced operating time

Engineering Contradiction:
Improvemeasurement system simplicityVSAvoidcontinuous filter monitoring
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements continuous monitoring of filter currents during normal operation, not just during startup. The measurement sensors and evaluation unit continuously track filter current values and compare them against reference values, enabling real-time detection of filter degradation or defects while the system is operating, thus maintaining continuous useful monitoring action.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent establishes a feedback loop where measured filter current values are continuously compared against reference values, and deviations trigger alerts or warnings. This feedback mechanism enables the system to respond to filter issues in real-time, allowing for proactive maintenance before complete failure occurs.

Inventive Principle:
Principle #23Feedback

3Device complexity

If high-power measuring sensors are used for filter current measurement, then no additional measurement equipment is needed, but the output currents are 10 to 100 times greater than filter currents, making precise determination impossible

Engineering Contradiction:
Improvemeasurement equipment quantityVSAvoidfilter current determination accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the measurement function by introducing a separate measurement channel with dedicated measurement sensors that are specifically designed for filter current ranges. This separates the high-power output measurement (handled by existing sensors) from the low-power filter current measurement (handled by new dedicated sensors), allowing each to be optimized for its specific range without compromise.

Inventive Principle:
Principle #1Segmentation

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 approach allows for precise monitoring of filter currents, enabling early detection of issues, reducing the risk of system failures, and minimizing downtime, especially in high-power devices like wind turbines, by allowing for timely replacement of components and optimizing maintenance schedules.

Implementation Method 1

the means for determining the at least one filter current comprise at least one current sensor for measuring the current in at least one phase of the at least one three-phase filter

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3254351B9Filter monitoring
Publication Date: 2021.08.18 CONVERTERTEC DEUT GMBH
  • EP3254351B9 patent drawingFigure 1~2
  • EP3254351B9 patent drawingFigure 3~5
  • EP3254351B9 patent drawingFigure 6

AI summary

The invention relates to an apparatus for delivering electrical power, in particular for delivering regeneratively produced electrical power, which has at least one converter (5, 6, 11, 12) and at least one filter (7, 8, 9, 14a, 14) for adapting the delivery of power by the converter to a load impedance. The problem addressed by the present invention, that of providing an apparatus for delivering electrical power and a corresponding method for operating an apparatus for delivering electrical power which allows improved monitoring of the method of operation of the filters or mains filters, is solved for an apparatus by providing means (7', 8', 9', 14a', 14') for determining at least one filter current in at least one filter, which means are designed in such a manner that said means make it possible to determine the at least one filter current during operation of the apparatus, wherein comparison means are provided and generate an error information signal using the desired value and actual value of the filter current and a predefinable error criterion.