Application of VSG Control in Microgrids with Unknown Frequency Dynamic of Diesel Generator

Virtual synchronous generator (VSG) control can improve the system inertia and frequency stability of microgrids including diesel generator and high penetration of renewable energy sources efficiently. In most of existing works, VSG parameters (such as effective damping and inertia) are always designed with known frequency dynamic of diesel generator. However, in most real applications, we cannot get the actual inertia and primary control parameters of diesel generator due to some reasons. Thus, how to apply appropriate VSG control in microgrids with unknown frequency dynamic of diesel generator has become the main motivation of this paper. A frequency dynamic identification method of diesel generator based on inertia and primary control parameters estimation is proposed firstly. Then, with the identified frequency dynamic of diesel generator, the frequency analysis model of the entire microgrid can be obtained, and the control parameter design optimization of VSG can be realized in practical microgrids to enhance the frequency stability. Finally, the proposed method and VSG control performance has been verified in a real experimental platform consisting of a 50kVA diesel generator and an energy storage system with a 50kVA DC-AC converter.