Decentralized PV-BES Coordination Control With Improved Dynamic Performance for Islanded Plug-n-Play DC Microgrid

In this article, a decentralized photovoltaic (PV)-battery energy storage (BES) coordination control method for Plug-n-Play (PnP) dc microgrid (MG) is proposed. With the proposed control method, PV units can operate under dc bus voltage control when BES units are saturated due to state-of-charge (SoC) limit or charging/discharging power limit. The mode transition and power sharing are based on a communication-less manner. By bypassing communication, the MG system can become more flexible and reliable. The proposed control system contains controllers for PV converter and BES converter, respectively. The PV converter controller can achieve seamless mode transition between maximum power point tracking (MPPT) control and droop control. The BES converter controller has a decoupled feature that a high-pass-filter (HPF) path could improve MG dynamic performance under generation-dominating mode. The BES HPF compensation overcomes the issue of poor dynamic performance under PV-dominating mode and makes the system more resistive to PV parameter variation. The detailed design, analysis, and implementation of the proposed PV-BES coordination control are provided in this article. The simulation and experimental results have been provided to verify the concept and analytical study.