An Improved Decentralized Control Strategy for PV-Hybrid-Energy-Storage System in LVDC Microgrid Provisionally Accepted

Jianbiao Li^{1, 2} Yong Chen^{1, 2} Yue Wu^3* Xu Cheng^{1, 2} Ruixiong Yang^{1, 2}

• ¹DC Power Distribution and Consumption Technology Research Center of Guangdong Power Grid Co., Ltd., China
• ²Zhuhai Power Supply Bureau of Guangdong Power Grid Co., Ltd., China
• ³Electric Power Research Institute of China South Power Grid, China

This paper introduces an improved decentralized control strategy for PV-hybrid-energy-storage (HES) system in DC microgrid. The power sharing method of the HES system is discussed in depth. The basic principle of virtual resistance and capacitance droop (VRCD) control, which consists of virtual resistance droop(VRD) and virtual capacitance droop (VCD) control, is analyzed in detail to achieve the decoupling of HES system for high and low frequency load power distribution. For the virtual capacitance control loop, the voltage compensator is added to achieve the terminal voltage restoration of the supercapacitor (SC). For the virtual resistance control loop, in order to solve the problems the unbalanced state of charge (SOC) of battery storage, a virtual resistance droop control based on a novel adaptive function is introduced. Finally, a model of HESS in DC microgrid is built in real-time emulator to verify the effectiveness of the proposed control strategy.