A Management Control Strategy of Photovoltaic-storage System Based on Virtual Synchronous Generator

Photovoltaic microgrid is an important integration way for renewable energy resources. However, such issues as strong fluctuation output of photovoltaic generators and lacking inertia have brought tremendous pressure on microgrid operation. In order to improve the operation stability and reliability of microgrid, a photovoltaic-storage system is formed by energy storage equipped at the photovoltaic generator side and an inverter controlled by virtual synchronous generator (VSG). Based on VSG, a management control strategy is designed for photovoltaic-storage system to coordinate and control the system. The core of control is to introduce such information as photovoltaic power output and the state of charge of storage equipment into VSG control. Then the droop characteristic of VSG is regulated by way of changing slope and shifting curve. According to the operation condition, photovoltaic-storage system would automatically changes the power and frequency output as well as the input of photovoltaic power. Thus the state of charge of storage equipment is controlled within a safe range. In the end, an autonomous wireless control of photovoltaic-storage system and the active support for microgrid are realized. Relevant theoretical analysis and proposed scheme is verified by the simulation system built with Matlab/Simulink tool.