Optimized Grid Power Injection with Maximum Power Point Tracking Using Cascaded SEPIC Converter and Three Phase Inverter

ABSTRACT: This paper presents modern single switch dc to dc converter modelling and control of a grid connected renewable energy. The system consists of a Photo voltaic cells, a SEPIC DC-DC converter used for Maximum Power Point Tracking (MPPT), a three-phase grid converter. A nonlinear control performance of a three-phase inverter is proposed to recompense unstable load currents. It permits whole control of DC bus voltage, while calculating power flow from the PV cells to the system and guarantying objective sinusoidal grid currents at unity Power factor under varying solar irradiation. Moreover, a sliding mode control system for a SEPIC DC-DC converter is used to extract the MPPT. The proposed control techniques have exposed good performance. The system is validated using the "Power system Block set" simulator under different values of the solar irradiation. KEYWORDS:Solar array, MPPT, SEPIC converter, Three level inverter, utility GRID. I.INTRODUCTION Energy from Photovoltaic source has been considered green energy as it does not pollute the environment and also it is renewable. Hence energy from PV source is considered to be an important source of energy among various renewable sources of energy. Now-a-days due to the advancement of technology in the field of manufacturing of PV cells the efficiency has been increased to such a level that the application of PV cells in power systems becomes a feasible one. In the recent period injecting the power obtained from the PV sources into to the grid becomes more popular as it is feasible to inject both active and reactive power into the grid thereby aiding the Electric Power network. Invariably whether the PV system is grid connected or standalone or hybrid system extraction of maximum possible power at a particular level of irradiation is very important as it increases the utility of the PV cells. . In most of the grid connected PV systems, the configuration consists of two stages such as a DC-DC converter in the front end to track the maximum power point at all possible atmospheric conditions and an inverter at the back end feeding the power extracted from the PV source by the front end converter into the grid. In the presented paper, a method has been proposed consisting of two stages, having a SEPIC converter at the front end and a three phase inverter at the back end, thereby maximum possible power extracted from the PV modules is injected into the power grid