Adaptive Coupling Reshaping Controller for Mitigating Unstable SSCI Between Renewable Energy Power Plants and Power Grids

Shunt converter-based damping schemes have been developed to mitigate the unstable subsynchronous control interaction (SSCI) between renewable energy power plants and power grids. However, varying system conditions can alter the dynamic interaction between shunt converters and power systems, making it challenging for these shunt converter-based damping schemes to provide consistently positive damping effects. To address the above-mentioned problem, this article proposes a coupled impedance model and an adaptive coupling reshaping controller (ACRC). First, a coupled impedance model, which considers the implicit coupling relationship between the shunt converter and the power system, is constructed to reveal the dynamic interactions between the shunt converter and the power system. Based on the coupled impedance model, an ACRC is proposed to adaptively reshape the coupling relationship. This online adjustment adaptive for various system conditions, equivalent to reshaping the dynamic interaction between the shunt converter and the power system, increases the grid resistance at the resonant frequency and hence effectively mitigates the SSCI. Finally, impedance-based analysis and controller-hardware-in-loop tests verify the effectiveness and adaptivity of the proposed method.