Robust Controller Design for Tracking Enhancement of a Grid-Tied PV-Battery Microgrid Under Industrial Loads

The concept of microgrid (MG) empowers the application of renewable energy sources (RES) to meet the increasing demand of electrical power, which further inspires us to enable this technology under the study of inverter-based industrial loads (IL). The inclusion of inverter-based IL adds some noises in the MGs dynamics because of the non-linear characteristics of inverter and parametric uncertainty of loads. The above constraints impose extra-challenges to maintain reliable operation of the MGs. In this paper, integral based linear quadratic gaussian (ILQG) controller is proposed to maintain the tracking operation via the control of inverter used with ILs, which is further connected with the dc bus which is regulated by the inverter in grid side and dc-dc converter applied in utility grid, PV and battery, respectively. The proposed ILQG controller is designed based on the proper combination of linear quadratic gaussian (LQG) and integral controller and its performance is evaluated by changing the operating conditions, which includes the switching of supplying power from PV, and both PV and battery. Additionally, the investigation under the variation of the IL parameters and comparison with resonant controller is used to ensure the robust performance of the ILQG controller.