Control Techniques for Grid Forming Inverters: A Comparative Analysis

Abstract

As renewable power generation is increasingly integrated with the grid, challenges arising from the removal of synchronous generation are being highlighted in research and in practice. The reduction of grid inertia due to large scale integration of inverter-based resources (IBR) has impacts on system strength and grid stability during transient events. Grid-Forming (GFM) inverters are gaining popularity for their ability to replicate the dynamics of synchronous generation. Serving as a voltage source coupled through a reactance, GFM inverters can regulate the voltage and frequency in a similar fashion to a bulk synchronous generator and are able to complete black start operations as well as operate independently, setting the grid frequency and voltage. There are several GFM control methods, three of which are implemented and analysed in this paper; droop control, dispatchable virtual oscillator (dVOC) and matching control. The MATLAB simulation results of each control method under steady state, and dynamic conditions under grid disturbances and faults in the DC and AC side of the converter is presented together with their comparative analysis.