Available online at www.ijapie.org International journal of advanced production and industrial engineering IJAPIE-2018-01-127, Vol 3 (1), 27-32 IJAPIE Connecting Science & Technology with Management. A Journal for all Products & Processes. Design & Simulation of Transformerless Power Convertors for Solar Application Soumya Sourav,Vikas Sharma,Vinayak Nadir, Siddharth Verma, J N Rai (Department of Electrical Engineering, Delhi Technological University,New Delhi, India) Email: vinayak_nadir@yahoo.co.in | IJAPIE | ISSN: 2455–8419 | www.ijapie.org | Vol. 3 | Issue. 1 | 2018 | 27 | Abstract : This paper presents simulation and design results for Transformerless Power Convertors which are to be used in conjunction with a PV array for solar applications. The set of converters consists of a boost converter as well as a single phase inverter for conversion of DC supply from the array to a usable AC voltage. The power extraction from the array is done by using the Maximum Power Point tracking (MPPT) algorithm. Simulation is done on Proteus and PSIM. Keywords: PV converter; transformer-less inverter; boost converter MPPT illumination. I. INTRODUCTION The dependency on the traditional non-renewable sources energy generation has not only led to fast depletion of the resources but also contributed to the degradation of our environment. There has been a growing consensus around the world to curb the use of these polluting resources and switch to more dependable and clean energy sources. A lot of renewable options are available like wind, hydro, geothermal and probably the most popular of them all solar. There has been a boom in the renewable energy market all around the world. This growing interest is quite visible by the exponential growth in the demand for Photo-Voltaic (PV) power. In general a PV inverter, converts the variable direct current (DC) output of a photovoltaic solar panel[3] into alternating current (AC) with the desired frequency that can be fed into a commercial electrical grid or used by a local, off-grid electrical network. The photo voltaic converters used presently generally employ a transformer. This leads to transformer losses. To combat these losses which present mainly in the form of heat a more efficient converter system is designed that does not use transformers for its functioning. Apart from high efficiency the transformer-less PV power convertors has several benefits which are low cost, small leakage current, low harmonic distortion and constant high frequency common mode voltage. Due to nonlinear i-v characteristics of a photo voltaic array, the Maximum Power Point tracking (MPPT) algorithm is used as it derives power by tracking the Maximum Power Point, which is the point where the product of current and voltage is maximum. The system designed is used as a standalone system and is not fed into the grid. II. DESIGN OF POWER CONVERTERS A. PV Array and MPPT Algorithm The photovoltaic array is a complete power-generating unit, consisting of any number of PV modules and panels. The output current and open circuit voltages are given by the following equations: The MPPT algorithm allows a PV array to deliver the maximum amount of energy to the desired system is known as maximum power point tracking (MPPT)[1]. These are highly reliable and accurate versions that allow us to maximize the charging ability of our PV array and, in some cases, reduce the required PV array size. MPPT controllers take the power from a PV array at the Maximum Power Point, regardless of the required voltage, and deliver that same amount of power (minus losses) to the boost converter (DC/DC) because they’re able to reduce the voltage from the array to the required level. B. DC to DC Boost and DC to AC Converters A DC to DC convertor (as shown in Fig. 1) is used to boost the voltage output from the MPPT Controller to a desired level. This voltage is the fed into the inverter. The key principle that drives the boost converter is the tendency of an inductor to resist changes in current by creating and destroying a magnetic field. In a boost converter, the output voltage is always higher than the input voltage. When the switch is closed, current flows through the inductor in clockwise direction and the inductor stores some