Abstract
Power quality is an important concern for practical microgrid (MG) applications due to the widespread use of non-linear loads, and it is characterised by the implicit trade-off between voltage quality in the MG nodes and harmonic current sharing between distributed generators (DGs). Active and passive filters can be used to address this problem. Nevertheless, modification of the control system of the DGs represents a cheaper and more practical solution. To this end, virtual impedances can be included in the controller. However, the power quality trade-off is difficult to adjust, especially in the presence of electrical distribution lines. In this paper, an optimisation algorithm for setting the harmonic virtual impedances of the DGs in a multibus MG is presented. This optimisation algorithm can be configured for any degree of harmonic current sharing between the DGs, while improving the voltage quality is set as the main objective. Compared to other works presented in the literature, power quality can be adequately managed without relying on time-critical communications since only the values of the harmonic virtual impedances are modified. Theoretica
