Active Harmonic Compensator for Grid Resonance Damping
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Solution Overview
Problem
Existing methods for compensating electrical harmonics on the grid, such as passive filters, are expensive and inefficient, particularly for power generating units like wind turbines and solar generators that generate significant harmonic distortion.
Innovation Solution
A control system comprising a harmonic compensator and an impedance detector that determines resonance frequencies and generates control inputs for power inverters to inject compensation currents, effectively damping harmonics at specific frequencies by processing measured currents and adjusting control gains based on impedance peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive filters are used for filtering undesired harmonics, then harmonic distortion is reduced, but cost and space requirements increase significantly
Solution Approach 1:
The patent replaces passive mechanical filters with an active control system using power electronic converters. The controller dynamically generates compensation currents through the converter to cancel harmonics, substituting the static passive filter approach with an active electronic control approach that reduces both cost and space while maintaining effectiveness.
Solution Approach 2:
The power producing unit itself provides harmonic compensation through its integrated controller and converter. The system uses its own power electronic components to generate compensation currents, making the unit self-sufficient for harmonic mitigation without requiring separate external passive filter installations.
2Productivity
If power producing units are connected to the grid, then power generation capacity increases, but harmonic distortion is generated
Solution Approach 1:
The patent converts the harmful harmonic currents generated by power producing units into beneficial compensation currents. The controller detects harmonics and instructs the converter to generate equal and opposite currents that cancel the distortion, transforming the units from harmonic sources into active participants in grid quality maintenance.
Solution Approach 2:
The system implements a feedback control mechanism where the controller continuously monitors grid conditions and power producing unit output, then adjusts converter control signals accordingly. This closed-loop feedback enables dynamic compensation that adapts to changing operating conditions while maintaining power generation capacity.
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 reduces harmonic distortion on the grid by injecting compensation currents that counteract harmonic oscillations at identified resonance frequencies, improving grid stability and reducing the need for costly passive filters.
Implementation Method 1
determine resonance frequencies by scanning impedances as a function of frequency... determine control input to the inverter for controlling generation of compensation current generation by the inverter, where the control input is determined on basis of the determined resonance frequency so that the current generated by the inverter is capable of compensating an electrical harmonic at a determined resonance frequency
Data Source
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AI summary
The invention relates to a control system for compensating undesired electrical harmonics on an electrical grid. Part of the control system referred to as a harmonic compensator is operatively connected with a power inverter of a power producing unit supplying power to the grid. Another part of the control system, referred to as an impedance detector, is operatively connected to a point of coupling to which point one or more power producing units are connected. The impedance detector is configured to scan impedances as a function of frequency to identify frequencies of impedance peaks which peaks are indicative of resonance frequencies. The determined resonance frequencies are supplied to one or more the harmonic compensators. A compensator determines control signals to the inverter which causes the inverter to inject compensation currents to the grid which currents will damp currents oscillating at or close to the determined resonance frequency.