Design and analysis of closed loop control of power-converters for forming droop-controlled AC-DC subgrids of an islanded hybrid AC-DC microgrid

Hybrid AC-DC microgrid (HMG) is formed by connecting separate AC and DC microgrids with an interlinking converter (IC). In islanded mode of operation of the HMG its AC and DC subgrids are droop controlled to achieve power-sharing. The power flow between the subgrids happens through the IC, which regulates the amount of power being transferred based on the values of the frequency of AC bus voltage and the voltage at the DC bus. This paper presents the utilization of power-electronic converters to form the droop-controlled AC-DC subgrids of an islanded HMG which will be beneficial for further studies of IC and HMG. The detailed design and analysis of the closed-loop control system parameters of both the power converters is presented. The results obtained from simulations carried out in MATLAB/Simulink, and the real-time simulation results obtained by implementation using OPAL-RT OP4500 real-time digital simulator hardware are presented for the verification.