Comparative Analysis of Primary Microgrid Control Through Adaptive VSG Based Multi-Loop and Single Loop Configuration

The future power system is anticipated to have a significant amount of distributed generation (DG) interfaced with inverters. Major concern is to control the inverters and provide stability to the microgrid system. Traditionally, the multiloop and single loop control topologies are extensively reported as to form grid-forming control in literature. Despite having so similar, the stability characteristics and dynamic performance of multi loop and single loop control are different. Virtual synchronous generator (VSG), has also been acknowledged as a powerful tool for microgrid control that helps the islanded power electronic systems through inertia and damping support. This paper explores the implementation of an adaptive VSG on the grid-forming multi-loop and single loop control configurations. A small signal stability model has been developed for both the configurations, based on which the stability assessment is performed. The same has also been verified through simulation studies as well. A typical microgrid, having three phase inverter with constant DC voltage input and an LC filter, connecting to the load through distribution line is considered for analysis. Detailed simulation studies are carried out in the MATLAB/SIMULINK environment in discretized mode to verify the effectiveness of both the control loops, at different loading conditions. Results demonstrate that the single loop control with reduced order and complexity is as efficient as the double loop control. Additionally, the suggested control technique has successfully undergone a processor-in-loop (PIL) validation utilizing a TI C2000 microcontroller.