RETRACTED: Robust Virtual Inertia Control of an Islanded Microgrid Considering High Penetration of Renewable Energy (Retracted article. See vol. 12, pg. 874, 2018)

This paper presents robust virtual inertia control of an islanded microgrid considering high penetration of renewable energy sources (RESs). In such microgrids, the lack of system inertia due to the replacement of traditional generating units with a large amount of RESs causes undesirable influence to microgrid frequency stability, leading to weakening of the microgrid. In order to handle this challenge, the H-infinity robust control method is implemented to the virtual inertial control loop, taking into account the high penetration of RESs, thus enhancing the robust performance and stability of the microgrid during contingencies. The controller's robustness and performance are determined along with numerous disturbances and parametric uncertainties. The comparative study between H-infinity and optimal proportional integral (PI)-based virtual inertia controller is also presented. The results show the superior robustness and control effect of the proposed H-infinity controller in terms of precise reference frequency tracking and disturbance attenuation over the optimal PI controller. It is validated that the proposed H-infinity-based virtual inertia controller successfully provides desired robust frequency support to a low-inertia islanded microgrid against high RESs penetration.