Evaluation of Bidirectional DC-DC Converter Topologies for Voltage Regulation in Hybrid Microgrids with Photovoltaic and Battery Technologies

High penetration of renewable sources, in the last years, is responsible for perturbations in the energy supply, because of their intermittent behavior. Such characteristics is responsible for reliability and power quality problems. To mitigate problems like voltage variation, regulation algorithms can be applied through the energy storage systems. The connection between the energy storage with power grid is carried out and managed by the DC-DC bidirectional converter. This paper presents a comparative evaluation of different topologies of DCDC bidirectional converters. The main objective is identify the topology with better performance for voltage regulation. The system analyzed is a hybrid microgrid composed for battery energy storage system and photovoltaic array connected to power grid. A variable solar irradiance is applied as input to photovoltaic system. The three topologies of DC-DC bidirectional converter approached are the buck-boost, cuk and multilevel. A same voltage regulation strategy is applied to each topology. The model of hybrid microgrid is developed in the software MatLab/Simulink. In this model, the DC-Link voltage ripple and the control response is analyzed. The simulation results show that the DC DC bidirectional multilevel converter has a more suitable response for voltage control. Thereby, the BESS using such topology allow an ancillary service with better power quality to the hybrid microgrid.