Equivalent Virtual Inductance Method without Differential Operation for Current-Limiting Control of Grid-Forming Converters

초록

This paper proposes a novel method to emulate virtual impedance (VI) for the current-limiting control (CLC) of grid-forming (GFM) converters. By leveraging the voltage at the point of common coupling (PCC), the proposed method enables the virtual amplification of the filter inductance without requiring a digital differentiator, thereby achieving a genuine emulation of physical inductance. The proposed VI method incorporating the virtual inductance can be adaptively increased based on the current magnitude for CLC. In contrast to conventional adaptive VI control based on algebraic impedance, which is prone to instability and requires a low-pass filter for stabilization, experimental results confirm that the proposed approach exhibits stable dynamic performance and effectively limits current during transients, while significantly reducing control complexity and design burden.

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