Supercapacitor application for PV power smoothing

Abstract

The penetration of renewable energy technologies causes grid stability problems and voltage flickering due to fluctuations of the weather conditions, which affect the produced renewable power. The system is first analyzed in order to define the operating point and the controlling parameters, in which the produced power is shared correctly between the load and the grid at a power factor close to unity. The operating point is set by the duty cycle (D) of the DC-DC converter, the depth of modulation (Dm) of the inverter, and the phase angle (δ) between the output voltage of the inverter and the grid voltage. The simulated system is operated in an open-loop mode in order to investigate the effect of each parameter without the corrective action of the closed-loops of the MPPT and the load angle. After that, a preliminary investigation of a supercapacitor controlled storage application is performed in terms of the power flow. All calculated theoretical results are verified by the simulation results. This research forms the basis for an in-depth investigation of supercapacitor and battery storage in grid-connected systems.