A Hybrid Energy Storage Based Control Strategy For Dispatchable Distributed Generation

Based on the analysis of the existing structure of hybrid energy storage system composed of battery and supercapacitor, a novel topological structure of dispatchable distributed generation based on hybrid energy storage is proposed. In this structure, coordinated control between various parts of the DC power supply system is studied. When the SOC of energy storage devices are within the limits, MPPT control is adopted in renewable energy generation system, the reference power of battery is determined by low pass filtering algorithm with compensating coefficient and constant voltage control is adopted in supercapacitor. When the SOC of energy storage devices reaches the limits, a novel mode switch control based on different voltage zones of DC bus is presented. To avoid the transient shock brought by frequent switching between various control modes, supercapacitor terminal voltage pre-control is proposed to prevent the SOC of supercapacitor reaching its limits. Finally, the performance of the proposed control strategy is verified by digital time-domain simulation studies in PSCAD/EMTDC software environment.