A new control method for leveling output frequency fluctuations in an autonomous PV/FC/UC network with maximum power point tracking of the photovoltaic system
Affiliations: Department of Electrical Engineering, Mashhad Branch, Islamic Azad University, Mashhad, Iran | Department of Electrical and Electronic Engineering, Shiraz University of Technology, Shiraz, Iran
Note: [] Corresponding author. Elham Ganji, Department of Electrical Engineering, Mashhad Branch, Islamic Azad University, Mashhad, Iran. Tel./Fax: +989366922343; E-mail: ellm.g.nn@gmail.com
Abstract: This paper presents a study on isolated hybrid distributed generation (DG) system combining solar photovoltaic (PV), fuel cell (FC) and ultra-capacitor (UC) for improving the frequency profile. The PV system is used as the main power generation source, while the long-term energy balance is supposed to be generated by FC, besides, as for the short-term compensation the UC is used. The PV is controlled to track the maximum power point at all operating conditions by employing an efficient robust terminal sliding mode controller (TSMC). The proposed MPPT controller guarantees fast convergence of MPP tracking and high robustness against PV system parameters variation. In this part, to demonstrate the effectiveness and reliability of the TSMC controller, comparison with Proportional Integral (PI) control was performed. In the following, with the optimization of droop controller by applying the Improved Particle Swarm Optimization (IPSO) algorithm the frequency deviation in the various states changing of generated power and consumed power declines significantly. To demonstrate the effectiveness of proposed frequency controller, optimal droop frequency controller using IPSO algorithm, is compared with conventional and improved droop controllers. Employing matlab/simulink® environment based on nonlinear detailed mathematical and dynamic models, simulation results under the real weather data and practical load demand profile are presented to validate the proposed scheme.
Keywords: Isolated hybrid system, frequency control, dynamic modeling, maximum power point tracking (MPPT), terminal sliding mode controller (TSMC), improved particle swarm optimization (IPSO), improved droop control
