A Four-Port Bi-directional DC/DC Converter for DC-Microgrids

Inhalt:
With distributed generation power can be directly generated and supplied to the area and large amount of losses can be saved. Distributed generation is realized using Microgrids, which are composed of generators and interconnected loads. DC Microgrids have a DC distributed network which is composed of several distributed power sources with the DC bus. DC Microgrids work at a higher efficiency because in ac systems power is wasted in ac to dc conversions. A drawback to such a system is that due to the different operating voltage levels of the DC grid, loads etc. a DC/DC converter with separate control is required at each stage. This creates lots of redundancy and hence is not cost effective. Therefore, the paper presents a solution by proposing a four port bidirectional dc/dc converter for connection with the external DC Microgrids, charging the battery, supplying DC loads and supplying or storing energy from the PV panel. The proposed four port converter combines four DC/DC converters into a single Multiport DC/DC converter. In the paper, the power flow equations of the proposed converter are also developed and verified in simulation using the well know Power Electronics Simulator PSIM. Hence, with this converter there is reduced redundancy, reduced cost, more power efficiency and it can provide more power density. Moreover, there is improved dynamic performance as no communication time exists between the control circuits as there is a centralized control.