A centralized control architecture for harmonic voltage suppression in islanded microgrids

This paper proposes a centralized control architecture for harmonic voltage suppression in islanded microgrids. The centralized selective harmonic compensator is developed in addition to the autonomous nonlinear load sharing loop in local controllers of inverter-interfaced Distributed Energy Resource (DER) units. Thus the harmonic voltage distortion caused by the mismatch between the harmonic conductance and characteristic impedance of the distribution feeder can be reduced. Moreover, to overcome the constraint on transmitting harmonic signals by a low-bandwidth communication line, a Park transformation aided signal modulation method is integrated to the centralized control architecture. The operation principle and case studies based on computer simulations are presented in this paper and validate the proposed control architecture.