FRT Capability Enhancement of Autonomous AC/DC Hybrid Microgrid by Coordinated MSDBR and Interlinking Converter Control Strategy

This paper presents a novel coordinated control strategy based on Modulated Series Dynamic Braking Resistor (MSDBR) and Interlinking Converter (IC) for the Fault Ride Through (FRT) capability enhancement of an islanded Hybrid AC/DC Microgrid (HMG). A simple fault detection algorithm is proposed based on the positive sequence voltage and line fault current magnitudes of the AC grid. The MSDBR is mainly employed to suppress the fault current and evacuate excessive active power during the fault. In order to control the AC voltage sags and swells on the MSDBR's post-operation, a supplementary reactive current control is applied to the IC. Simulations have been performed by the MATLAB\Simulink software. Both symmetrical and asymmetrical faults are considered on the line connecting the load in the AC sub-grid. The time-domain simulation results show that the proposed strategy efficiently suppresses the fault current while providing positive sequence voltage recovery. Thus, the proposed strategy is effective for the HMG system.