International Journal of Innovative Technology and Exploring Engineering (IJITEE) ISSN: 2278-3075, Volume-9 Issue-4, February 2020 1942 Published By: Blue Eyes Intelligence Engineering & Sciences Publication Retrieval Number: D1645029420/2020©BEIESP DOI:10.35940/ijitee.D1645.029420 Abstract; This paper presents multifunctional operation capability of three level cascade H bridge inverter for grid connected solar pv application. The solar panel and inverter are modelled for unbalance and nonlinear loads with three control techniques (pq,dq,cpt) and its performance is simulated in the MATLAB environment using SIMULINK and Sim Power System (SPS) toolboxes. The performance of inverter is evaluated for harmonics elimination, power factor correction apart from active and reactive power support to grid and nonlinear load .Performance of three level H bridge inverter is evaluated for both PV mode and STATCOM mode using three control techniques for distribution grid. Keywords: Active power filters, Cascaded H-bridge inverters, Compensation strategies, Conservative power theory, space vector modulation. I. INTRODUCTION In the last few decades, solar energy has been one of the most active research areas among renewable-energy sources. Photovoltaic systems connected to the electrical power grid are gaining more and more popularity as demand for energy is increasing worldwide. Multilevel inverters have been attracting more and more attention in the past few years as power converters in high voltage and high power grid connected applications due to their improved voltage qualities over the conventional two-level inverters. These MLIs with appropriate control improves the performance of the grid connected energy sources, even at lower switching frequencies with lesser filter components [1] [2]. The conventional grid connected inverters employ two stages of power converters for photovoltaic applications. The first stage is a dc/dc boost converter which is connected to the PV panel and tries to extract the maximum power from PV panels. The next stage is a voltage source converter which tries to transfer the electric power into the grid at unity power factor. This kind of PV inverter, however, will lead to higher losses and complexity compared to single stage inverters due to insertion of dc/dc converters thus single stage transformer less topologies are becoming more popular due to compact size and higher efficiency. Smart inverters can perform multiple functions involving both reactive and real power control in addition to their main task of converting DC power to AC power. Revised Manuscript Received on January 20, 2020. Darshni M. Shukla, Assistant Professor, Department of Electrical Engineering, Government Engineering College, Surat, India. E-mail: darshnishukla@yahoo.com Naimish Zaveri, Professor, Department of Electrical Engineering, CK Pithawala College of Engineering &Technology, College Surat, India. These functions include voltage regulation, power factor control, active power controls, fault ride through, and frequency control, etc. Many research is going on to eliminate the usage of other reactive power compensation schemes by exploring multifunctional capability of inverter. The smart control of inverter is basically the ability to supply real power to local load up to the rated capacity of inverter and provide voltage support at the point of common coupling (PCC). Grid interconnection standards are also is being revised to facilitate the adoption of smart inverter functions [7].Among the various topologies, of MLIs the cascaded H-bridge (CHB) inverter is especially interesting for photovoltaic (PV) applications as it needs the minimum number of components for synthesizing the same number of voltage levels. It also provides several distinct DC links which allow the independent control of PV arrays [4] [5] [6]. The power conditioning stage interfacing the PV modules to the grid has attracted the attention of researchers. Several power conditioning methods and control strategies have been introducing for harmonics, reactive and unbalanced current compensation [11] [12].Active and reactive power control of three level inverter is proposed in [14] while active filtering capability of three level cascade H bridge inverter for various control is explore in [15].Most of the paper found in literature explore one or two functionality along with active power integration to grid. Multiple functionality of smart inverter proposed by various researcher is combined in this work. The lineament of this paper is comparative analysis of the three most popular grid control techniques proposed in the literature to control three phase three level H- bridge inverter based photovoltaic plant. To explore its multifunctional capability the Maximum power point (MPP) control without DC/DC converter is also incorporated and develop a smart control for three level three phase voltage source inverter (VSI) which enables a Photovoltaic Power plant (PV) to operate as active filter, reactive power compensation, power factor correction and STATCOM in addition to operating as a source of renewable power generation. Different control methods are applied for power conditioning and hysteresis PWM is used for switching of the inverter and the performance of inverter will be analyzed and evaluated. The rest of the paper is organized under the following headings. Performance of Three Level H-Bridge Inverter in Grid Connected Solar PV for Multifunctional Operations using Different Control Techniques Darshni M. Shukla, Naimish Zaveri