The Partial Power Processing Converter System with Robust DC-Link Voltage for Islanded DC Microgrid

The partial power processing (PPP) converter systems are extensively studied for embedding renewable energy sources into the strong ac system. However, the existing PPP converter structures can only meet the requirement of renewable energy sources such as the maximum power point tracking (MPPT) of photovoltaic (PV), and the constant total dc-link voltage cannot be obtained for the islanded dc microgrid. Thus, a novel PPP structure is proposed in this paper, which can realize the independent control of renewable energy source and the stabilization of the total dc-link voltage. Moreover, the dual-active-bridge (DAB) dc-dc converter is selected to verify the effectiveness of the PPP system. In addition, by using the PV as an example, a high-robustness control strategy is proposed for maintaining the dc-link voltage when the working condition of the renewable energy source, the output voltage of the battery and the load condition are changed. Finally, simulation results and experiment results will be provided to verify the effectiveness of the proposed PPP converter system and the proposed high-robustness control scheme with fast-dynamic response.