Modeling, analysis, and design of a frequency-droop-based virtual synchronous generator for microgrid applications

In this paper, a power-frequency (P-ω) controller is presented for voltage source converters (VSC). The approach is intended for multiple parallel VSCs forming a microgrid operating in both grid-connected and islanded modes. The proposed controller allows a VSC to mimic the operation of a synchronous generator (SG) by implementing the swing equation of SG with a primary frequency controller. In addition, a generalized model of the active power generation dynamics is developed in order to analyze the stability and to design the main control parameters. In contrast with the conventional droop control method, the proposed controller improves the close-loop system dynamic response without changing the frequency accuracy. The obtained results show the good performance of the proposed controller.