Small Signal Modelling of Compensator based Virtual Synchronous Generator in Islanded AC Microgrid

Abstract

Conventional droop with current and voltage control is a popular technique for control of grid forming converters in islanded AC microgrids. Several emerging inertia based techniques such as synchronverter and virtual synchronous generator(VSG) have been used for the control of the microgrid. This paper presents the controller design of the compensator based VSG and its linearized small signal model. The small signal model is developed for several such inverters interconnected through impedances with different loads at the buses. The network used for small signal stability analysis is validated through 4 Distributed Generators(DGs) connected to 4 buses with different loads such as resistive load, inductive load, constant power load(CPL) and rectifier interfaced active load(RIAL). The operating point is obtained by simulating the microgrid in Real time digital simulator(RTDS) for the eigenvalue analysis. Unstable modes are detected through eigenvalue analysis, and a participation factor analysis is conducted to identify the states that influence these unstable modes. © 2023 IEEE.