Abstract: Now a day, renewable of energy of different sources is attracted the various researchers and investors for the research work. The photovoltaic system is the best example of the energy renewable, because of it is suitable for different applications like as distributed generation, satellite systems, and transportation. In this paper, a single-phase seven-level inverter (DC-AC Converter) based on photovoltaic system for grid connection is presents. The proposed system uses single-stage transformer which has photovoltaic array for the interfacing to the grid and it has maximum power. Three reference signals that are identical to each other with an offset that is equivalent to the amplitude of the triangular carrier signal were used to generate the PWM signals. The inverter is capable of producing seven levels of output-voltage levels (Vdc, 2Vdc/3, Vdc/3, 0,-Vdc,-2Vdc/3, -Vdc/3) from the dc supply voltage. A digital proportional–integral current-control algorithm was implemented in a PIC 30F2010 to keep the current injected into the grid sinusoidal for dc bus voltage 400V.To magnetize the dc-link inductor a modified carrier based modulation technique is used in this paper. The experimental results of the proposed system show the dynamic performance and power quality.
Keywords: DC-AC Converter, Grid-Connected, Photovoltaic (PV) system, Pulse Width-Modulation(PWM), Total Harmonic Distortion (THD),Maximum Power Point (MPP) etc.