Grid-friendly matching of synchronous machines by tapping into the DC storage

Abstract

We propose a novel control strategy for grid-forming converters in low-inertia power grids. Our strategy is inspired by identifying the structural similarities between the 3-phase DC/AC converter and the synchronous machine model. We explicitly match these models through modulation control so that they become structurally equivalent. Compared to standard emulation of virtual synchronous machines, our controller relies solely on readily available DC-side measurements and takes into account the natural DC and AC storage elements which are usually neglected. As a result, our controller is generally faster and less vulnerable to delays and measurement inaccuracies. We provide a virtual adaptive oscillator interpretation of our controller various plug-and-play properties of the closed loop, such as passivity with respect to the DC and AC ports as well as the steady-state droop slopes, which we illustrate in simulations.