A Cost-Efficient Virtual Synchronous Generator System Based on Coordinated Photovoltaic and Supercapacitor
Jia Liu, Yuguang Hou, Jingyu Guo, Xinyu Liu, Jinjun Liu
Abstract
Virtual synchronous generator (VSG) control is widely adopted in grid-connected inverters owing to its ability of inertia support and primary frequency regulation. However, these benefits are achieved at the increased cost of energy storage (ES). Therefore, a cost-efficient grid-forming VSG system based on coordinated photovoltaic (PV) and supercapacitor (SC) is proposed in this article. Considering the different features of reserved PV power and SC, we propose a coordinating control to make the SC tackles short-term high power whereas the reserved PV power provides long-term low power. A novel cost-efficient transient energy sharing between short-term and long-term energy provision is proposed, along with its parameter design procedure, to optimize the cost of curtailed PV energy and SC investment. Moreover, we propose an improved PV-SC-VSG control scheme to further reduce the ES both in the dc-link and the SC. Experimental results validate the effectiveness of the proposed control strategy.