Harmonic Virtual Impedance Design for Optimal Management of Power Quality in Microgrids
Challenge and objective
Power quality is an important concern for practical microgrid (MG) applications due to the widespread use of nonlinear loads.
It is characterized by the implicit trade-off between voltage quality in the MG nodes and harmonic current sharing between distributed generators (DGs).
Instead of using more costly alternatives as filters, this work addresses the modification of the control system of the DGs that represents a cheaper and more practical solution. Virtual impedances (VIs) can be included in the controller to improve current sharing.
An optimization algorithm for setting the harmonic VIs of the DGs in a multibus MG is developed where the objective is voltage quality improvement.
This optimization algorithm can be configured for any degree of harmonic current sharing between the DGs.
Impact for distribution system innovation
Less costly alternatives will become available to maintain power quality in microgrid applications.