Grid-Frequency-Independent Static Var Compensator Control Using a Synchronous Phase-Carrier with Direct Firing Instant Determination for Leading Load Compensation in Renewable Energy DC Bus

Static var compensators (SVCs) employing thyristor-controlled reactors (TCRs) are widely used to mitigate power-factor degradation by absorbing lagging reactive power. Conventional TCR control schemes use real-time firing-angle calculations, which require intensive computation and make practical real-time implementation difficult, especially under grid frequency variations. To address this issue, this paper proposes a grid-frequency-independent SVC control method based on a synchronous phase carrier technique that directly determines thyristor firing instants without explicit firing-angle calculations. The proposed control strategy uses a carrier signal synchronized with the system phase, enabling real-time TCR operation without relying on nominal grid frequency. The effectiveness of the proposed method is evaluated through simulations and hardware experiments. The results show that the proposed method ensures reliable real-time operation and improves the power factor without requiring firing-angle computation. Furthermore, stable performance under grid-frequency variations confirms the robustness of the proposed method. The proposed approach provides a practical and reliable solution for mitigating power-factor degradation in modern power systems.