Sub-/Super-Synchronous Resonance Mitigation Method Based on Impedance Reshaping for Grid-Tied Black-Box Converters

Impedance reshaping effectively solves the sub-/super-synchronous resonance (SSR) problem of grid-tied converters. However, such a method requires a white-box model, i.e., the control model and parameters of converters are known, which is difficult to achieve in practical scenarios. To address this issue, this paper proposes a novel impedance reshaping method for black-box converters. Firstly, the impedance method is used to analyze the stability of the grid-tied black-box converters. Then, a novel impedance reshaping method is proposed based on an additional control loop. This method is simple and easy-implemented. In the case of SSR, only the input voltage signal of the phase-locked loop (PLL) needs to be compensated by the additional control. Finally, various time-domain simulations verify the effectiveness and robustness of the proposed method.