Seeker optimization approach to dynamic PI based virtual impedance drooping for economic load sharing between PV and SOFC in an islanded microgrid

Abstract

Nowadays Load Sharing has been an emerging trend, necessary for the integration of multiple distributed generators (DGs) into the microgrid system through sophisticated power electronics converters. Proper sharing of load ascertains the utilities with increased energy cost efficiency, reliability, stability and protects the system from being overloaded. This work puts forth a novel control technique for proportional load sharing among parallel VSCs connected to an islanded microgrid in a distributed generating system consisting of Photovoltaic (PV) and Solid Oxide Fuel Cell (SOFC) as two micro sources. For tracking maximum solar energy a Mamdani Fuzzy Logic Controller (MFLC) based self-tuned Dynamic PI Controller (DPIC) is implemented for the Modified Perturb and Observe MPPT method. Also for the optimum cost management of the microgrid system, DPIC based communication less Virtual Impedance Drooping (VID) technique is implemented for suitable load sharing between the two hybrid micro sources. In order to further enhance the performance of the DPIC, the Membership function parameters are optimized using a heuristic computational algorithm named Seeker Optimization Approach (SOA). SOA computes the optimum value of the Membership function parameters for the MFLC and thus avoids the use of constant input valued parameters. The dynamic response and stability of the system with proposed method is compared and contrasted with DPIC during load sharing for ensuring robust control under conditions of linear and nonlinear loads. Validation and justification of the improvements achieved by the proposed controller are realized using MATLAB/Simulink environment.