Virtual Synchronous Generator with Self-adaptive Power Regulation Ability in Microgrid

Abstract

The concept of virtual synchronous generator (VSG) is regarded to be a friendly grid-connected method for renewable energies. As the VSG can participate in grid power regulation automatically as conventional generators, a reserve capacity is needed when the VSG operates at rated power, and the stronger power regulation ability of the VSG, the larger reserve capacity is needed. However, a large reserve capacity will result in low hardware utilization because the VSGs used for renewable energies connection can only operate at rated power in few time. In this paper, a modified VSG with self-adaptive power regulation ability is proposed by adopting a variable unit power regulation coefficient based on fuzzy logical controller. The modified VSG can regulate its power regulation ability automatically according to its output power and the deviation value of the system frequency, thus, a small reserve capacity is needed when the VSG operates at rated power to improve its hardware utilization, meanwhile, the VSG will get a stronger power regulation ability when it operates on light-load to improve the transient characteristics of the microgrid. A microgrid model was built based on Matlab/Simulink and simulation results proved the modified VSG to be effective.