Int. J. Adv. Sci. Eng. Vol. 3 No.3 404-406 (2017) 404 ISSN 2349 5359 Saichithraa et al International Journal of Advanced Science and Engineering www.mahendrapublications.com ABSTRACT: Three-phase transformer inverter is commonly used in photovoltaic (PV) grid-connected systems due to its high efficiency and low cost. There is no galvanic connection. In these conditions, common mode leakage. Currents can appear through the capacitance between the PV array and the ground. In order to create a galvanic isolation between the input and the output include a transformer that reduces the whole system performances in terms of efficiency, weight, size and cost. On the contrary, transformer less inverters absent of any isolation and are characterized by little size, lower cost and higher efficiency (more t h a n 2 % higher). The s h o r t a g e o f transformers leads to leakage currents that can be harmful to the human body, as well as for the whole conversion system integrity. Triggering pulses are given using Pulse Modulation (PWM) technique through Data Acquisition (DAQ). In order to reduce the ground leakage current and improve the efficiency of the converter system, transformer less PV inverters by using of unipolar PWM control is proposed. In this paper, a three-phase grid based inverter that operates the super junction Metal Oxide Semiconductor Field-Effect Transistor (MOSFET) to accomplish high efficiency for photovoltaic applications is introduced. Also three phase transformer less inverter with Permanent Magnet Synchronous Motor (PMSM) under LabVIEW platform is developed. Keywords: PMSM drive, Renewable energy source, PWM Controller, LabVIEW © 2016 mahendrapublications.com, All rights reserved *Corresponding Author: umamaheswaria@mahendra.info Received: 05.01.2017 Accepted: 25.02.2017 Published on: 28.02.2017 PV Grid based Inverter by PMSM Drive using LABVIEW C. Saichithraa, S. Umamaheshwari, B.S. Rajan Department of Electronics and Electrical Engineering, Mahendra Engineering College, Mahendhirapuri, Mallasamudram - 637 503, Namakkal District, India I.INTRODUCTION Energy demand is increasing due to increase of the human populations and quick increasing of industries. Hence, renewable energy sources are playing a vital role to reduce the use of conventional sources like fuel and coal. In generally, two grid tied PV systems are used, one is with transformer and other is without transformer. In this work, transformer less inverters with grid connected photovoltaic systems is used to decrease the leakage current and better efficiency performance. Since the MOSFET switching device is used, it gives high reliability, low output distortion and decreasing of CM leakage current. And also it does not have any shoot through issues, because of usage of PWM technique in inverter [1,2]. In addition the proposed converter is able to produce higher switching frequencies which reduce the ripple content and size of the components. Three phase grid tied transformer less inverter for PV system by using of PMSM drive is developed using LabVIEW platform. Compare to other text programming, LabVIEW is more flexible and user friendly because of its easy understanding and flexible wiring with relevant blocks. LabVIEW is commonly used for data acquisition, instrument control, and industrial automation on a variety of platforms including Microsoft Windows, various flavors of UNIX, Linux, and Mac OS X. The DAQ card used here is NI DAQ USB 6221 and the triggering pulses are given to the PWM inverter through the LabVIEW-DAQ through which the signals are given to the inverter and to the motor. A. PMSM Drive A PMSM uses permanent magnet embedded in the steel rotor to create a constant magnetic field. The stator carries windings connected to an AC supply to produce a rotating magnetic field. PMSM motors are similar to brushless DC motor because of the constant magnetic field in the rotor and it does not use induction windings for starting. These motors are requires variable frequency power source to start. B. PV System Solar refers to a panel designed to absorb the sun's rays as a source of energy for generating electricity or heat. Most solar modules are currently produced from silicon PV cells. These are typically categorized into either monocrystalline or multicrystalline modules. A solar panel is a packaged, interconnected assembly of solar cells, and also known as photovoltaic cells. The solar panel can be used as a component of a larger photovoltaic system to generate and supply electricity in commercial and residential applications. II.Three Phase Topology And Operation Analysis Fig.1 shows the block diagram of three phase grid connected to photovoltaic with PMSM drive using LabVIEW. Modules are connected in parallel to create strings and the PMSM drive is connected in parallel with the output. Fault detection is easy to identify using LabVIEW. In this work, MOSFET is used as H- bridge circuit hence frequent switching does not affect the motor. Since transformer less PV inverters is used, ground leakage current is minimum. Fig.2 shows the proposed transformer less PV inverter, which composes of six MOSFET switches (S1–S6), six diodes (D1–D6), and two split ac-coupled inductors L1 and L2. The diodes D1–D4 doe’s voltage clamping functions for active switches S1–S4. The AC-side switch pairs are composed of S5, D5 and S6, D6, respectively, which provide unidirectional current flow branches during the freewheeling phases.