A Selective Power Droop Control for Hybrid Interlinking Converter in AC/LVDC Microgrid

Abstract

This article proposed a selective power droop control for a hybrid interlinking converter (HIC) in connecting ac grid with low-voltage DC (LVDC) grid. The direct connection to the LVDC means relatively lower converter capacity, lower switching loss, higher efficiency, and lower cost in HIC. However, the small capacity converter and large capacitive coupling impedance of HIC can lead to a relatively lower reactive power compensation range. Therefore, the practical overcapacity situation may be more likely to occur in HIC, which deteriorates the system performance. To address this issue, the unique P-δ and Q-P-V droops are proposed for HIC with automatic selective factors adjustment control. With the proposed control method, the HIC can effectively regulate active/reactive powers and improve power quality. To demonstrate the validity of the proposed structure and its control method, a 5-kW HIC is built, and results are presented for poor power quality situations. The results convincingly indicate that the proposed HIC is efficient and capable of low capacity advantage, multifunction control strategy, and overcapacity operation.