Enhanced Control Strategy of Back-to-Back Interfacing Converters Between Microgrid and Utility

To facilitate needed active and reactive power flow between utility and microgrid, this research presents an enhanced power flow control of back-to-back interfacing converters between microgrid and utility. The system can operate to distribute real and reactive power equally between the utility and the microgrid based on the microgrid load power requirement. The open-loop power control proposed by Ritwik Majumder et al. relies on knowing the point of common coupling (PCC) voltage amplitude $(V_{P})$, angle $(\delta_{P})$, and reactance $(X_{G})$. These parameters may not be available due to the considerable distance between the PCC bus and the back-to-back interfacing converters. These flaws are addressed in the method of control used in this paper. Besides, a harmonic compensation strategy is incorporated in the power control of a back-to-back interfacing converters to improve the microgrid PCC voltage quality, which has been deteriorated by nonlinear loads connected to the PCC bus. In microgrid DGs inverters, traditional droop control is used to provide power sharing for the remaining load demand. To lessen the voltage dip in the grid, a low-voltage grid support, also known as dynamic grid voltage support, is incorporated in the grid side converter of back-to-back converters. The grid voltage dip is reduced by the reactive power injection. The control techniques are verified using simulation in PSCAD software.