A Multi-port High Step-up DC/DC Converter for Hybrid Renewable Energy Application

This paper presents a novel multi-port DC/DC converter which is suitable to be used as the interface of hybrid renewable energy systems. The converter contains three unidirectional power flow ports which two of them are input ports and are connected to two independent energy sources while the third one is the output port that feeds a standalone load. Furthermore, the proposed converter contains a bidirectional power flow port to charge/discharge an energy storage system (battery). In addition to multi-port structure, high boost value of voltage gain is the other merit of the converter. Hybrid system is composed of fuel cell (FC), photovoltaic (PV) panels and a battery pack. Different operating states are discussed, and a control system based on decoupling networks is presented. The control system is able to seek and extract maximum power of PV panel, adjust generated power of FC, and handle charging and discharging modes of battery. In order to control operating modes of the proposed converter, a power management method is also presented. By the way, small signal model is presented for the converter.The bode diagram has been plotted from the small signal model. Then the controller it was designed from the bode diagram. The results of simulation by the PI controller are presented. Also, the simulation results by P&O algorithm for the converter has been evaluated. Several Simulation and experimental tests have been carried out to evaluate the analysis and feasibility of the aforementioned system. The results verify well performance of the converter and confirm the simulations and theoretical results.

Keywords:

Hybrid renewable energy , Photovoltaic , Fuel cell , DC/DC Converter , multiport converters