International Journal of Engineering Research and Development e-ISSN: 2278-067X, p-ISSN: 2278-800X, www.ijerd.com Volume 10, Issue 12 (December 2014), PP.25-36 25 A Novel High Step-Up DC–DC Converter for Hybrid Renewable Energy System applied to Irrigation 1 G.Anjali, 2 G.Madhavi 1 Mtech student, electrical and electronics engineering, P.V.P.Siddhartha institute of chnology, Krishna, A.P, India 2 Assistant professor, electrical and electronics engineering, P.V.P. Siddhartha institute of technology, Krishna, A.P, India Abstract:- Large electric drives and utility applications require advanced power electronics converter to meet the high power demands. As a result, power converter structure has been introduced as an alternative in high power and medium voltage situations using Renewable energy sources (RES). This paper describes a new DC/DC converter with safety, high efficiency and high step up capabilities. This converter is best suited for Wind/Fuel cell(FC)based Induction Motor applications for pumping systems. The safety feature of this converter makes it friendly for the farmers to use it for irrigation and agriculture usages. The converter achieves high step-up voltage gain with appropriate duty ratio and low voltage stress on the power switches. Also, the energy stored in the leakage inductor of the coupled inductor can be recycled to the output. The maximum output voltage is determined by the number of the capacitors. The capacitors are charged in parallel and are discharged in series by the coupled inductor, stacking on the output capacitor. Thus, the proposed converter can achieve high step-up voltage gain with appropriate duty ratio and interfaced to induction motor through 9-level inverter and also energy fed to grid system when no load operation. The simulation results are obtained using MATLAB/SIMULINK software. Keywords:- Coupled-inductor, high step-up voltage gain, switched capacitor, three phase inverter, gird connection. I. INTRODUCTION Renewable energy sources (RESs) have experienced a rapid growth in the last decade due to technological improvements, which have progressively reduced their costs and increased their efficiency at the same time [1]. Moreover, the need to depend less on fossil fuels and to reduce emissions of greenhouse gases, requires an increase of the electricity produced by RESs. This can be accomplished mainly by resorting to wind and photovoltaic generation, which, however, introduces several problems in electric systems management due to the inherent nature of these kinds of RESs [2]. In fact, they are both characterized by poorly predictable energy production profiles, together with highly variable rates. As a consequence, the electric system cannot manage these intermittent power sources beyond certain limits, resulting in RES generation curtailments and, hence, the RES penetration levels are lower than expected. Here front-end DC-DC converter is required for conversion of energy from one stage to another and interfaced to grid/load through inverter topology. The DC-DC boost converter is used for voltage step-up applications, and in this case this converter will be operated at extremely high duty ratio to achieve high step-up voltage gain [1],[2]. However, the voltage gain and the efficiency are limited due to the constraining effect of power switches, diodes, and the equivalent series resistance (ESR) of inductors and capacitors. Based on the structure a switched capacitor (SC) converter is one of the good solutions to low power and high gain DC-DC conversion. The advantage is that this kind of SC converter uses semiconductor switches and capacitors only. However, most SC circuits have a voltage gain proportional to the number of pumping capacitors. Generally speaking, high step-up converter is used for this application which requires high voltage gain, and efficiency [5], [6]. To achieve high step-up voltage gain, many converters have been proposed. Some converters effectively combined both boost and flyback converters as one and other different converter combinations are developed to carry out high step-up volt-age gain by using the coupled-inductor technique. High voltage gain is restricted by the voltage stress on the active switch. But in case of coupled inductor technique the energy of the leakage inductor can be recycled that will reduce the voltage stress on active switch. This leads the coupled inductor technique more successful.