High-Frequency Self-Stabilizing Control for a Grid-Tied VSC

Existing methods, which incorporate low-pass or band-pass filters into voltage feedforward control (VFC) to suppress high-frequency oscillation (HFO) in grid-tied voltagesource converters (VSCs), may not be effective under varying grid conditions and could potentially degrade the VSC's dynamic characteristics. To address these issues, this paper proposes a high-frequency self-stabilizing control (HFSSC) for the grid-tied VSC, which considers the additional resistance effect (ARE) of the phase-locked loop (PLL). The ARE refers to the PLL-induced enhancement effect on high-frequency resistance of the VSC, and its inherent mechanism is explained. It is a crucial factor in designing the HFSSC suitable for various grid settings. The HFSSC consists of the nonlinear VFC and the active damping control. It achieves a positive resistance characteristic for the gridtied VSC above 200 Hz, thereby mitigating the risk of HFO under diverse grid operating conditions without compromising the dynamic characteristics of the grid-tied VSC. The design process of the parameters for the proposed HFSSC is also elaborated upon. Ultimately, experimental results are provided to substantiate the efficacy of the proposed method.