Comparative Study of Decentralized Grid-forming Converter Controls For Inverter-based Microgrids

With the heavy integration of Inverter-based Resources (IBR) into the different levels of the electrical network, they are gradually required to replace the conventional Synchronous Machines (SM) in maintaining the network voltage and frequency references. Such Grid-forming (GFM) controllers recently reported in literature include conventional Droop control, nonlinear oscillator-based controls, namely the dispatchable Virtual Oscillator Control (dVOC), Synchronverter and Matching controls. This article aims to reveal the underlying resemblance between these grid-forming controls and the conventional Droop-based strategies being the most commonly used in the decentralized and hierarchical control of Microgrids (MG). Based on the derived similarities in their dynamics, tuning the different controllers’ parameters to achieve equivalent transient and steady state dynamics maintaining P-f and Q-V relations is deduced and validated using time domain simulations.