IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE) e-ISSN: 2278-1676,p-ISSN: 2320-3331, Volume 13, Issue 6 Ver. I (Nov. – Dec. 2018), PP 07-13 www.iosrjournals.org DOI: 10.9790/1676-1306010713 www.iosrjournals.org 7 | Page Harmonic Minimization in 31-Level Cascaded Multilevel Inverter Topology with Reduced Number of Switches Koyyana Srinivasa Rao 1 , K.Nagamani 2 , Dhanunjaya Naidu 3 1 Asst.professor, Dept. of EEE, Lendi institute of engineering and technology, AP, India 2 Asst.professor, Dept. of EEE, Lendi institute of engineering and technology, AP, India 3 Asst.professor, Dept. of EEE, Lendi institute of engineering and technology, AP, India Corresponding Author: Koyyana Srinivasa Rao Abstract: Multilevel inverters are power electronic devices that changes over DC to AC quantity. But these devices produces non-sinusoidal signal which contains harmonics. So as to be overcome this problem a 31-level cascaded multilevel inverter topology was developed. The proposed inverter topology has been designed based on the minimum number of switches, switching power losses and total harmonic distortion[THD] when compared to the symmetrical seven level and asymmetrical fifteen level inverter topology. The simulation results are presented showing the validity of the analysis. Index terms: multilevel inverter, power electronics, fundamental switches -------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 12-12-2018 Date of acceptance: 27-12-2018 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction Multilevel power conversion was first introduced more than twenty years ago. The multilevel inverter has drawn tremendous interest in the power in the power industry. They present a new set of features that are well suited for use in reactive power compensation. By using multilevel inverter to produce quality output voltage or a current waveform with minimum amount of ripple content. It can be possible by using more number of active semiconductor switches to perform conversion in small voltages steps. There are several advantages in process when compare to the conventional power conversion approach. One area where multilevel converters are mostly suitable is that of renewable photovoltaic energy that efficiency and power quality are of concerns for the researchers. Multilevel inverter mostly popular area where the numbers of switches are reduced. This paper discusses the operation of different topologies for multilevel inverter which can produce multilevel. The multilevel inverter concept is the kind of alternation of two-level inverter. The general structure consists of four switches found in the single phase inverter is to create a sinusoidal voltage from several levels of voltages, typically obtained from capacitor voltage sources. The main motivation for such inverter is that the current is shared among these multiple switches, allowing a high inverter power rating than the individual switch VA rating. Otherwise it allows harmonics. As the number of level increase, the synthesized output waveform. Several types of multilevel inverter topologies, which have been reported from high power inverter system manufactures. The most commonly used topologies are diode clamped, flying capacitor, cascaded H- Bridge and modified H-bridge multilevel inverter topologies. These three topologies employ different mechanism to produce the required output. But requirement switches are more and power loss also more. For example symmetrical seven level multilevel inverter require 10 switches. II. Cascaded multilevel inverter A cascaded multilevel inverter has of number of H-bridge inverter units associated in series and they are sustained from discrete DC sources. As they yield is taken in series, the DC sources must be isolate from each other. Therefore, cascaded multilevel inverter is additional been proposed to be utilized with energy components or photovoltaic clusters keeping in mind the goal to accomplish higher voltage level. The subsequent AC yield voltage is the expansion of the voltages produced by various H- bridge cells. Each bridge has the property to create three levels as +V dc, 0, -V dc by associating the DC source to the AC yield and by various mixes of four switches where V dc is the input voltages of the H- bridge.