Active Filtering System for Powerline Communication Interference

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Solution Overview

Problem

Existing passive filtering systems for current harmonics in the 2 kHz to 150 kHz frequency band are bulky, difficult to implement, and costly, failing to effectively address the interference with electrical networks and Powerline Communication technology.

Innovation Solution

An active filtering system comprising a controlled current generator with a capacitor, voltage converter, and control device using analog and/or digital components, with two separate control loops to generate a compensation current that filters out disturbing currents, utilizing low-voltage transistors and a simple control law to maintain a sawtooth profile for effective current regulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If passive filtering systems using copper windings are used, then filtering of current harmonics is achieved, but the system becomes bulky and difficult to implement

Engineering Contradiction:

Improvefiltering effectivenessVSAvoidsystem size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent replaces the mechanical/passive copper winding filtering system with an active electronic filtering system using transistors, capacitors, and control circuits. This substitution eliminates the need for bulky copper windings while maintaining filtering effectiveness through active compensation of harmonic currents.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the operating parameters by using low-voltage transistors with switching frequencies in the range of 2 kHz to 150 kHz, which allows effective filtering without requiring large physical components. The active control mechanism dynamically adjusts compensation current based on detected harmonic content.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If passive filtering systems are used, then current harmonics are filtered, but the system becomes costly and complex to implement

Engineering Contradiction:

Improvefiltering effectivenessVSAvoidimplementation complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex passive filtering components with a simpler active control system based on low-voltage transistors and standard electronic components. The control logic uses straightforward voltage threshold comparison and complementary switching, reducing implementation complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention uses inexpensive low-voltage transistors and standard electronic components that are readily available and cost-effective, replacing expensive passive filtering components. The system achieves reliable filtering through intelligent control rather than expensive hardware.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Volume of moving object

If active filtering system with low-voltage transistors is used, then system compactness and cost are reduced, but control complexity increases

Engineering Contradiction:

Improvesystem sizeVSAvoidcontrol complexity

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The control system is segmented into two independent complementary control loops, each handling specific voltage thresholds. This segmentation simplifies the overall control logic by dividing it into manageable, non-interacting segments that can be implemented using simple voltage comparators and logic circuits.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system employs periodic switching action of the transistors at frequencies between 2 kHz and 150 kHz, which simplifies control by using regular periodic pulses rather than continuous complex modulation. The periodic nature allows simple timing-based control logic.

Inventive Principle:

Principle #19Periodic 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 system achieves efficient filtering of high-frequency components, reducing network interference and allowing normal frequency supply, with a compact, cost-effective, and simple implementation.

Implementation Method 1

a capacitor (C) connected on one side to the first power line of the network and on the other side in series with the current generator (1)

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3179619B1Active filtering system

Publication Date: 2023.05.10 SCHNEIDER ELECTRIC IT CORP

Figure 1
Figure 2

AI summary

The invention relates to an active filtering system arranged to be connected in parallel with an electrical power supply network providing a main supply current (IMAIN) including a disturbing current, said system comprising: - at least one capacitor (C), - a controlled current generator having a power supply intended to generate a determined positive voltage (+VDC) or a determined negative voltage (-VDC) and connected in series with the capacitor, - a control device for the controlled current generator (1), arranged to generate a compensation current (ICAPA) to be applied to the main current in order to compensate for said disturbing current (INOISE) while maintaining a decoupling voltage (VDEC) measured at the point of connection between the current generator (1) and said capacitor at a value suitable so as not to saturate the current generator.