Second-order LADRC to enhance Droop-based Grid-Forming converters in inductive networks

With the rise of power electronics, Grid-Forming (GFM) converter controls are proposed to control the voltage magnitude and frequency. These controls are able to provide a virtual inertia to stabilize the frequency. However, the majority of these control dynamics depends on the state of the power system network (e.g. the power system reactance). This dependance is not suitable for Grid-Forming controls. Some network states may infringe the IEEE 2800-2022 standard. To solve this issue, this work proposes a Linear Active Disturbance Rejection Control (LADRC) for Droop-based Grid-Forming controls. Its use enhances the responsiveness and robustness of Droop-based Grid-Forming controls. This work shows that by using LADRC in Grid-Forming converters a robust active power response is obtained regarding grid reactance variations in inductive networks. This robust behaviour is developed in detail through its mathematical formulation and numerical simulations.