Robust control of an islanded multi-bus microgrid based on input-output feedback linearisation and sliding mode control

This study presents a robust control scheme for a multi-bus islanded microgrid (MG) consisting of a medium-voltage distribution system and several inverter-based distributed generation (DG) units. Adopting the master/slave structure in islanded MGs, a robust voltage controller is proposed based on adaptive sliding mode control to force the voltage magnitude and frequency of the master DG unit to track predefined trajectories. In addition, to regulate the output active and reactive powers of slave units, a direct power controller is proposed based on adaptive input-output feedback linearisation. The presented control scheme is performed based on local measurements and is designed independent from topology, parameters, and dynamics of the MG loads. Moreover, to overcome the computational burden associated with the tracking of MG voltage phase and frame transformations, the proposed control scheme is performed in stationary reference frame. The control methods proposed in this study are shown to be very well robust and stable against various disturbances and MG parameters uncertainties. The validity and effectiveness of the proposed control strategy is demonstrated based on time-domain simulation studies in the MATLAB/SIMULINK environment.