Unbalance Compensation in Stand-alone Microgrids

− The study presented in this paper aims to develop a new method for active and reactive power balancing in a four-wire stand-alone microgrid (MG), which feds single phase loads. Two unbalance compensation controllers are used, for active and reactive powers. The compensation is based on a dump load (DL) and a static compensator (STATCOM), which ensure the balance of the active and reactive powers. The DL has the main role of frequency controller, but it is used for active power balancing between phases, too. The STATCOM accomplishes only the redistribution of the reactive power unbalance between phases, not the power factor correction. Thus, its rated power is low, according to the maximum reactive power unbalance that can be expected in the MG. This combination of the power converters ensures a good power quality, regarding the MG power balancing. Simulations and experiments were carried out, both showing the effectiveness of the proposed solution.