INVESTIGATION OF A MULTIFUNCTIONAL GRID-TIED PHOTOVOLTAIC INVERTER SYSTEM FOR POWER QUALITY IMPROVEMENT

Abstract

This M.Sc thesis present the high gain DC-DC converter (HGDDC) for solar photovoltaic system (SPVs) with a multi-functional grid-tied inverter (MFGTI). The HGDDC step up the low SPVs voltage to a constant high gain DC voltage then to be easily integrated with utility grid voltage, at meantime to minimize the voltage ripple and reduce the stress of switches at output bus bar. In addition MFGTI convert the stepped up high gain voltage into demanded three phase utility grid voltage. While integrating the high gain voltage with utility grid voltage there are challenges like: grid voltage synchronization and power quality problems that are happened to the system due to non-linear loads, and SPVs irradiation changes. Therefore, to overcome of the grid synchronization and power quality issues, such as total current harmonic distortion, reactive power and to enhance the power factor, the author proposed a developed SRF control topology based on artificial neural network (ANN) techniques. This topology enable the MFGTI to inject the active power of SPVs to the utility gird Simulteniously to compensate the reactive power, reduce the total current harmonic, to enhance the power factor of the system and at main time to maintain the dc link voltage with very less voltage fluctuation. Eventually, the simulated results validate the satisfactory working of the proposed control topology under various solar irradiation, and nonlinear load conditions, it’s worthy to mention by implementing the mention topology the total current harmonics of the system reduced within IEEE-519 standards. To the end, a comparison study between ANN controller and dynamic PI of the synchronize reference frame (SRF) control theory are tested. Several simulations and prototype results are depicted to verify and validate the influenced of ANN based control. The proposed model is performed by MATLAB®/Simulink software, and the prototype work is done through Arduino Atmega 2560 controller.