Partially Isolated Three-Port DC-DC Converter and Battery Storage

In this thesis, three-port converters (TPC) are surveyed and a partially isolated three-port dc/dc converter is presented based on [1]. The converter under study manages the power supplied from multiple sources and delivers to the load a continuous power at the required voltage. These sources can be any solar distributed generation and/or energy storage system, i.e. batteries. Traditionally, two separate converters would be used to manage DG systems. However, a three-port converter is chosen due to the benefits it provides to users, such as cost and efficiency. The converter has a four-winding transformer, and one of its windings works as a magnetic switch to provide a continuous input current. The battery port supports the DG system continuously to provide a stable output power and to supply the load when the PV input is insufficient. The converter has three control loops that control the operation of the three-port converter to ensure the stability of the output power. The controllers select the mode of operation based on the amount of energy that the PV and the battery ports provide which in turn controls the battery's charging and discharging modes. Maximum power point tracking is utilized to provide a maximum PV input voltage. The analysis and simulation results verify the operation of this power system.