Analysis, modeling, and control of electric spring for a DC microgrid with high penetration of renewable energies to improve its stability and power quality

Abstract

It has been more than a century since the AC-based power system dominated the electric power business upon superior performance against DC-based power systems. The AC power system can supply the clients by transferring the generated power over a long distance. However, modern power systems are supposed not just cost-effective, but also sustainable. The DC system inherently is more reliable and robust and could be adopted locally for power delivery. Finally, the idea of a DC microgrid, as a solution for future smart grids has gained attraction due to its several advantages. The DC microgrid can operate based on DC power and They offer all the advantages of DC networks plus the ability to operate grid-connected or off-grid for electrification of remote areas. Despite all the advantages related to the concept of DC microgrids, there are still challenges regarding their operation and control in the presence of massively integrated renewable energy resources exacerbated by their natural intermittent production characteristics. This issue is more important in microgrids, especially in the off-grid operation mode, which relies mostly on PVs and wind turbines. To overcome this dilemma, employing new control schemes seems necessary for maintaining the balance between consumption and generation. Several solutions are proposed in the literature e.g., demand-side management, load balancing, real-time energy management system, and energy storage. In this thesis, our focus is on a very modern method proposed in the literature which is the application of electric springs for improving the performance of DC microgrids. We propose an energy-sharing scheme for coordinating the role of a DC electric spring (DCES) and a hybrid battery energy source system (hybrid BESS) for improving the DC bus voltage when the main source of the DC microgrid is a PV system. Then two contingencies are studied: (1)a cloudy situation is simulated in which the production of the main PV system drops, (2) a DC bus to ground fault. The simulation results prove that DCES can effectively and positively contribute to the steady-state stability of the DC bus, dampen the oscillations, improves the quality of provided power and voltage, and release the stress from the hybrid BESS.

Date	25 Jul 2023
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Ambrish Chandra (Supervisor)