Grid Impedance Estimation via Excitation of $LCL$ -Filter Resonance

By Marco Liserre, Frede Blaabjerg, Remus Teodorescu. IEEE transactions on industry applications, 2005

203 citations recorded by the source corpus.

Inverters adopted in distributed power generation, active filter, and uninterruptible power supply are often connected to the grid through an inductance-capacitor-inductance (LCL) filter. The impedance of the LCL filter has a typical frequency characteristic with a resonance peak. Hence, the LCL filter has to be damped in order to avoid instability. However, the resonance of the LCL filter can be also excited in a controlled way in order to individuate the resonance frequency in the spectrum (using for example the fast Fourier transform). This paper proposes to use a controlled excitation in measuring the grid impedance, since this one influences also the resonance frequency. This paper will address some possible limits, some solutions, and some implementation issues (e.g., how to obtain a controlled resonance in the filter without damaging the system) in order to use the resonant peak for grid impedance detection. The analysis is validated both by simulations and experimental results.

Subfields: Control and Systems Engineering, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/0d1af6ebb964455bb40fddf97d66307245ce9cc3

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Control and Systems Engineering

In Electrical and Electronic Engineering

Citations in the corpus

Minimal Invasive Equivalent Grid Impedance Estimation in Inductive–Resistive Power Networks Using Extended Kalman Filter (2014, methodology): “ods), in active methods [21]–[24] (or invasive methods) and in quasi-passive methods [25]–[27].”
Filter-Based Active Damping of Voltage Source Converters With $LCL$ Filter (2011, background): “In fact, ωRes can be estimated by triggering in a controlled way the resonance of the filter [ 48 ].”
Online Grid Impedance Measurement Using Discrete-Interval Binary Sequence Injection (2013, background): “popular in grid-impedance measurements and stability analysis [6]–[10].”