Topology and Control Strategy of a High-Voltage and Large-Capacity DC Direct-Mounted Energy Storage Device

Transmitting the large-scale offshore wind power to the onshore collection station using DC system and equipping DC direct-mounted energy storage in the DC side of the collection station is a promising technology scheme. However, existing studies on the DC direct-mounted energy storage are very limited. In view of this, a DC direct-mounted energy storage device suitable for the high-voltage and large-capacity scenarios is proposed in this paper. Firstly, the topology of the proposed DC direct-mounted energy storage is introduced. Then, its control strategies are designed for different application requirements, including the DC voltage control mode, the DC current control mode and the DC power control mode. Finally, simulations in PSCAD/EMTDC are conducted under power step-change and onshore AC faults scenarios to verify the effectiveness and performance of the proposed topology and control strategies.