Nonsingular Terminal Sliding Mode Control for Islanded Inverter-Based Microgrids

Due to the development of renewable energy and the need for sustainable electricity, AC microgrids (MGs) have received a lot of attention and the growing need for them is becoming more and more apparent. Medium voltage MGs will be very important in providing electrical energy in the near future. This paper represents a robust and effective control method with rather simple implementation capability for islanded MGs based on master-slave (MS) technique. The designed control is a type of terminal sliding mode control, which has a high response speed and good convergence with robustness against some uncertainties. Stability and high performance are very essential for islanded MGs. The designed control meets these requirements so that the output voltage of the inverter based distributed generation (DG) sources includes a very low amount of harmonics and the generated active and reactive powers track their reference values perfectly. The effectiveness of the proposed control method is evaluated by simulation in SIMULINK/MATLAB environment. The simulation results are presented considering five cases, which include feedback linearization control (FLC) and conventional sliding mode control (CSMC) of DGs, harmonic load and high impedance transmission lines simulation results. The obtained results show the perfect  tracking  and  robustness  of  the proposed control scheme considering uncertainties in parameters and it is illustrated that a high accuracy power sharing between DG sources is achieved.