Adaptive Virtual Synchronous Generator Control for Grid Forming Inverters in Islanded AC Microgrid - A Real Time Simulation

Due to the increasing penetration of renewable energy resources in distribution power systems, maintaining system stability has grown as a major concern in system operation. The distributed generators (DGs) used in the microgrid are interconnected to the grid through power electronic converters which do not provide any mechanical inertia due to which the stability issues arise in the grid. This paper focuses on control techniques for grid-forming inverters in islanded mode. This paper proposes an adaptive virtual synchronous generator (VSG) control for the grid forming inverter, in which online control of moment of inertia and damping coefficient are exercised to improve the frequency response in the islanded operation of AC microgrid. A simple microgrid including, a three-phase inverter, in which the input is fed by a DC voltage, and coupled to the load via LC filter, is considered for the simulation study. Different loading scenarios are studied with loads of type constant impedance, constant power, non-linear and dynamic load. To check the efficacy of the proposed scheme, real-time simulation is executed through the TYPHOON HIL-402 device. The real-time simulation results demonstrate the superior performance of adaptive VSG control over the conventional VSG control and droop control techniques.