IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE) e-ISSN: 2278-1676,p-ISSN: 2320-3331, PP 90-99 www.iosrjournals.org 2 nd International Conference On Innovations In Electrical & Electronics Engineering 90 | Page (ICIEEE) Grid Connected Photovoltaic System with Single stage Buck- Boost Inverter Ch.Srinivas Reddy 1 , G.Ranga Purushotham 2 , P.Parthasaradhi Reddy 3 Assistant Professor Associate Professor Associate Professor GNITC GNITC GNITC Abstract: For very high voltage gain of a Photo-Voltaic system, this paper proposed a buck-boost inverter of single stage. DCM (Discontinuous conduction mode) and MPPT (maximum power point tracking) is employed to get one power factor. Minimization of switching losses is employed with only two switches and operated at very high frequency. Easy control capability, optimum size, affordable cost with high voltage gain made the system employable. AC voltage conversion is achieved along with boosting of DC voltage of Photo-Voltaic system of inverter. Obstacle shadow variations also reduced by means of having the possibility of reduced series connected modules; this ability is due to the high voltage gain. Since the proposed design has the two buck boost converter each one operates for only one half cycle and the Discontinuous conduction mode operates at unit power factor. Simulation results assure the proposed idea of the single stage interleaved inverter for high voltage gain applications. Index Terms: Single Stage, Buck-Boost Inverter, Low-Cost,Grid-Connected, PV system, Simple-Control, DCM, MPPT. I. INTRODUCTION This Reference [1] gives clear idea about the difference between single stage and two stage inverters and the advantages of single stage inverter over two stage inverter. This paper also put forward different single stage inverter topologies and detailed comparison with this topology is presented. A complete st ea dy-state analysi s, including the design procedure and expressions for peak device stresses, is included. Necessary condition on the modulation index ―M‖ for sinusoidal pulse width modulated control of this inverter topology has also been derived for discontinuous conduction mode operation. All the analytical, simulation and experimental results are presented. Reference [2] gives idea about switching structures. These structures when used with buck, boost or buck –boost systems the gain of the systems is increased/ decreased. The main advantage of the switched structure converters is their lower energy in the magnetic elements, what leads to weight, size and cost saving for the inductors, and thus for the power supply, and less conduction losses, what leads to a better efficiency. New single-stage grid-connected inverter, suitable for distributed generation applications, is proposed. The inverter is universal in the sense that it can be switched between buck, boost, and buck– boost configurations by appropriately altering the pulse width modular (PWM) control. Discontinuous current mode (DCM) operation is implemented to facilitate shuffling between configurations during the converter operation. Such flexibility ensures maximum benefit of the buck, boost, and the buck–boost operations (e.g., low device stresses, higher efficiency, higher boosting capability, etc.). II. SWITCHED INDUCTOR BUCK-BOOST CONVERTER A true inverter takes power from a fixed dc source and applies it to an ac load such as a utility grid, an ac motor, a loudspeaker or a conventional product normally powered from an ac line. It is useful to distinguish two types of ac loads, active and passive. The utility grid is the most familiar active ac load. The utility waveform is controlled very precisely at a central location. A converter connected to the grid cannot alter the timing of the sinusoid. Hence, phase delay control is used as the adjustment tool. Real ac loads often include magnetic transformers, which only function with ac signals. If dc voltage is imposed on a transformer, it can cause the flux to increase until the device no longer functions. This is the key consideration in inverters: Any dc component is unwanted and in fact can cause considerable trouble. A practical inverter circuits should not produce any dc output component. Inverter applications usually use some type of transistor with reverse-parallel diode to give it bi-