Abstract:
The aim of the present work is to improve the
Power Quality (PQ) under the islanded mode of operation for
single phase MicroGrid (MG). For this purpose, a novel voltagesensorless, selective harmonic compensation scheme and a unified
two-dimensional modified droop control strategy for resonance
damping using only the inverter side current measurements is
utilized. Due to the lack of grid support under the islanded
operation of MG, load sharing of both fundamental and harmonic
load power among parallel inverters relies on the inverter control
strategy and the effective impedance between inverter and Point
of Common Coupling (PCC). Thus, the sensorless voltage method
is utilized to reshape effective impedance at various selected
harmonic components and subsequent resonance propagation is
controlled using resonance damping strategy by simultaneous
control of inverter output resistance and reactance between
inverter and PCC. The proposed method not only improves the
voltage quality at PCC but also reduces the reactive and harmonic
sharing errors in accordance with the ratings. The method is
validated on a simple system of parallel connected DGs in PSCAD
software.
