Virtual Impedance Applied for Stabilizing Distribution Power Grid Systems.
Renewable Energy, Photovoltaic, Voltage-Source Inverter, Virtual Impedance.
Virtual impedance concept has been increasingly used in power electronics-based
Power systems. Virtual-impedance-based control schemes provide a way of shaping
converters dynamic profile, primarily using a circuit-oriented control concept, with the
advantage of having no power losses. Using virtual impedances for output impedance
control allows converters to provide auxiliary functions as power flow control, grid fault
ride-through, harmonic compensation, and improve converter stability against different
grid and load conditions. This master’s thesis qualifying proposes an implementation of
virtual impedance-based control scheme on a photovoltaic system grid-connected three phase
inverter. Different virtual impedance implementations and their functions are presented.
The photovoltaic system considered and virtual impedance-based control scheme
are described, and simulation results are presented. At last, preliminary experimental
results of practical impedance implementation are presented.