A High-Robust Control Scheme for the DAB-based PPP Energy Storage System

The energy storage system become more and more important for dealing with the difference between the renewable energy system and the load requirements in islanded dc microgrid. Traditionally, the energy storage system is connected to the dc bus through the dc-dc converter, and usually, multiple energy storage sources such as batteries are required to provide sufficient power capacity, which will increase the cost of the converter system. Thus, based on the partial power processing (PPP) concept, a simple dual-active-bridge (DAB)-based PPP energy storage system is presented for reducing the use of switches, and this converter system can inherit the high-efficiency characteristic of the PPP structure. Moreover, a high-robust control scheme is proposed for this DAB-based PPP converter system for dealing with the change of the load condition, which can provide a stable dc-link voltage for the load consumer. Besides, the state of charge (SOC) balance among different batteries can be realized by configuring different power sharing coefficients among different DABs. Finally, simulation results and experiment results will be provided to verify the effectiveness of the presented DAB-based PPP energy storage system and the proposed high-robust control scheme with fast-dynamic response.