International Journal on Recent and Innovation Trends in Computing and Communication ISSN: 2321-8169 Volume: 4 Issue: 3 84 - 94 _______________________________________________________________________________________ 84 IJRITCC | March 2016, Available @ http://www.ijritcc.org _______________________________________________________________________________________ Simulation of High Step-Up Resonant Parallel LC Converter for Grid Connected Renewable Energy Sources G Hima Bindu 1 , K Venkata Reddy 2 , CH Rami Reddy 3 bindug212@gmail.com kattavenkatareddy@hotmail.com crreddy229@gmail.com Abstract:- With the rapid improvement of large-scale renewable energy sources and HVDC grid, it is a capable alternative to connect the renewable energy sources to the HVDC grid with a pure dc system, in which high-power high-voltage step-up dc–dc converters are the key equipment to transmit the electrical energy. This paper presents a High step up LC converter it can achieve high voltage gain using an LC parallel resonant tank.Also provided zero voltage switching (ZVS) technology under switch turn- On condition also at turn-Off conditions at main power switches by rectifying diodes to reduce the conduction losses. The operation principle of the converter and its resonant parameter selection is presented in this paper. The operation principle of the converter has been successfully verified with the help of MATLAB/SIMULINK. Keywords — Renewable energy, resonant converter, soft switching, voltage step-up, voltage stress. __________________________________________________*****_________________________________________________ I.INTRODUCTION The development of renewable energy sources is crucial to relieve the pressures of exhaustion of the fossil fuel and environmental pollution. At present, most of the renewable energy sources are utilized with the form of ac power. The generation equipments of the renewable energy sources and energy storage devices usually contain dc conversion stages and the produced electrical energy is delivered to the power grid through dc/ac stages, resulting in additional energy loss. Moreover, the common problem of the renewable energy sources, such as wind and solar, is the large variations of output power, and the connection of large scale of the renewable sources to the power grid is a huge challenge for the traditional electrical equipment, grid structure, and operation. DC grid, as one of the solutions to the aforementioned issues, is an emerging and promising approach which has drawn much attention recently [1]–[4]. At present, the voltages over the dc stages in the generation equipments of the renewable energy sources are relatively low, in the range of several hundred volts to several thousand volts hence, high-power high-voltage step-up dc–dc converters are required to deliver the produced electrical energy to the HVDC grid. Furthermore, as the connectors between the renewable energy sources and HVDC grid, the step-up dc–dc converters not only transmit electrical energy, but also isolate or buff kinds of fault conditions; they are one of the key equipments in the dc grid [5]. As of late, the powerful high- voltage step up dc–dc converters has been concentrated broadly [6]-[9]. The transformer is an advantageous way to deal with acknowledge voltage step up. The excellent full-connect (FB) converter, single dynamic extension (SAB) converter, what's more, LCC full converter are concentrated on and their execution is looked at for the offshore wind farm application[6] . The three-stage topologies, for example, three-stage SAB converter, arrangement resonant converter, and double dynamic extension converter, which are more suitable for high-control applications because of reduced current anxiety of every scaffold, are additionally contemplated furthermore, intended for high-control high-voltage step up applications [10]. The rising particular dc–dc converter, which utilizes two secluded multilevel converters connected by a medium frequency transformer, is appropriate for the application in the HVDC matrix [11]. For these disengaged topologies, the primary deterrent is the creation of the powerful high-voltage medium-recurrence transformer and there is no report about the transformer model yet. Multiple small- capacity isolated converters connected in series and/or parallel to form a high-power high-voltage converter is an effective means to avoid the use of single large-capacity transformer [12]–[14]. For the application where galvanic isolation is not mandatory, the use of a transformer would only increase the cost, volume, and losses, especially for high-power high-voltage applications [15]. Several nonisolated topologies for high-power high-voltage applications have recently been proposed and studied in the literature [16]–[17]. A boost converter is adapted by the researchers of Converteam company to transmit energy from ± 50 to ± 200 kV [18]. To obtain the higher voltage gain, Enjeti et al. proposed a multiple-module structure, which consists of a boost converter and