Design and Analysis of a High-Efficiency All-SiC Dynamic Voltage Restorer for Wide-Range Sag/Swell Mitigation

This paper presents the design, modeling, and simulation process of a 30-kVA dynamic voltage restorer (DVR) layout for the compensation of voltage sags and swells ranging from 0.2 to 2 p.u. of the nominal grid voltage for up to 60 s. The converter is supplied by a battery energy storage system (BESS) and reaches analytical peak efficiency above 99%, by using silicon carbide (SiC) power MOSFETs and an improved circuit architecture. The circuit topology combines a T-Type inverter and a three-phase-interleaved bidirectional dc-dc stage in a dual-dc-port structure, where most of the energy flows from/to the battery directly through the inverter, while the dc-dc stage is only enabled to handle heavy sags/swells at low battery charge. The architecture, control strategy and efficiency analysis are examined in this work, relying on a simulation workflow developed in MATLAB/Simulink. A comparison of the proposed converter design to other DVR topologies is also made to demonstrate the efficiency improvement.