A Multiport Converter Interfacing Solar Photovoltaic Modules and Energy Storage With DC Microgrid

In this article, a novel multiport converter (MPC) to interface different solar photovoltaic modules (SPM), and the battery with a 380 V dc microgrid is proposed. It is ensured that all the photovoltaic modules are operated at their respective maximum power points (MPPs), which is a unique feature of the proposed scheme. The boosting of the low voltages of the SPMs and that of the battery to 380 V is accomplished by involving a dc-dc converter along with a high-frequency transformer. The battery banks are charged directly from the power of the SPM without involving the high-frequency transformer. This significantly reduces the power flow path within the system. The MPC can operate in stand-alone mode or in microgrid connected mode as and when required. In the microgrid-connected mode, it is capable of realizing the MPP tracking, and at the same time, it is able to control the charging current of the battery as per the requirement of its charge controller. When MPC is operated in stand-alone mode, the voltage across the local loads are regulated at 380 V. The proposed MPC is modeled using the first component approximation method to facilitate the design of the appropriate controllers. The effectiveness of the proposed scheme is established by performing detailed simulation studies. A hardware prototype of the MPC is fabricated. Detailed experimental studies are carried out utilizing the developed prototype to confirm the viability of the proposed scheme.