An analytical approach to total harmonic distortion reduction in multi-level inverters

2010 ◽  
Author(s):  
Kfir J. Dagan ◽  
Raul Rabinovici ◽  
Dmitry Baimel
Keyword(s):  
Analytical Approach ◽  
Harmonic Distortion ◽  
Total Harmonic Distortion ◽  
Multi Level ◽  
Distortion Reduction

scholarly journals Performance Research of Seven Level Multi-Level Inverter with Reduced Switches using Various PWM Techniques

2019 ◽  
Vol 8 (2S8) ◽  
pp. 1149-1154
Keyword(s):  
High Power ◽  
Harmonic Distortion ◽  
Total Harmonic Distortion ◽  
Switching Topology ◽  
Switching Loss ◽  
Medium Voltage ◽  
Switching Losses ◽  
Multi Level ◽  
Low Efficiency ◽  
Performance Research

A inverter is basically a device that usually converts DC to AC voltage without causing any power loss, applicable to only low to medium voltage applications. But in case of medium to high power applications, it has demerits like high switching losses, reduced cost and low efficiency. To overcome these demerits a Multilevel inverter applicable to high voltage and high-power applications which have low total harmonic distortion (THD) is introduced. This paper is mainly focused on seven-level inverter with five switches and four dc sources. with low total harmonic distortion, less switching loss without adding any complexity to the circuit. The switching topology is integrated with various SPWM techniques like Phase Disposition (PD), Phase Opposition Disposition (POD) and Anti Phase Opposition Disposition (APOD). For better performance of the inverter above three PWM techniques will be compared and analyzed to find the low THD configuration. The simulation of switching topology is done by MATLAB/Simulink.

scholarly journals Harmonics reduction of a five-level inverter by unbalanced carriers and over-modulation techniques

2018 ◽  
Vol 7 (3) ◽  
pp. 1059
Author(s):  
Mustafa Fawzi Mohammed ◽  
Ali Husain Ahmad ◽  
AbdulRahim Thiab Humod
Keyword(s):  
Fundamental Frequency ◽  
Output Voltage ◽  
Single Phase ◽  
Harmonic Distortion ◽  
Total Harmonic Distortion ◽  
Modulation Method ◽  
Labview Software ◽  
Design And Implementation ◽  
Modulation Techniques ◽  
Multi Level

The most concerns in the inverter's design are about, how to make the output voltage of the inverter sinusoidal at the desired fundamental frequency with low total harmonic distortion (THD). This paper presents a design and implementation of single-phase five-level inverter which is powered by single dc source and based on T-type multi-level inverters construction. The proposed inverter is built mainly by six IGBTs and two diodes. The used modulation technique is based on using two triangular carriers at 2000 Hz frequency and shifted by phase opposition disposition (POD) method. The carriers are made slightly unbalanced with their amplitudes. The over-modulation method is also introduced in the design to get the lowest possible THD effect without using filters. The inverter is simulated by MATLAB SIMULINK, implemented practically, and tested with the help of LabVIEW software.  

scholarly journals Comparative Study of Total Harmonic Distortion in Multilevel Inverters Based WECS

2018 ◽  
Vol 7 (3.1) ◽  
pp. 42
Author(s):  
B Kandavel ◽  
G Uvaraj ◽  
M Manikandan
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Harmonic Distortion ◽  
Multilevel Inverter ◽  
Total Harmonic Distortion ◽  
Multilevel Inverters ◽  
Wind Speeds ◽  
Harmonic Content ◽  
Multi Level ◽  
Sinusoidal Pulse Width Modulation

This paper presents comparative study of Total Harmonic Distortion (THD) and its individual harmonic contents without grid and with grid for Diode clamped multi level inverter (DCMLI) and Flying capacitor clamped multilevel inverter (FCMLI) based Doubly Fed Induction Generator (DFIG) employing PI and Fuzzy logic controller (FLC). Simple method to control for a variable speed wind energy conversion system with a DFIG is connected to the grid through a diode rectifier and a diode clamped multilevel inverter (DCMLI). The DC-link voltage is controlled through a DC-DC boost converter to keep the DC voltage at constant value. Inverter is controlled by sinusoidal pulse width modulation technique, which supplies power to the grid. The THD and its harmonic content are studied for different wind speeds. DFIG fed flying capacitor multi level inverter (FCMLI) based WECS connected to load as well as grid. FCMLI is controlled through sinusoidal pulse width modulation. Voltage and current harmonics are studied. The results of both multilevel inverters are compared. It shows that the level of harmonic content of two types of multilevel inverters working at different wind speeds indicates that Total Harmonic Distortion (THD) for DCMLI has given best results.  

scholarly journals Symmetrical and Asymmetrical Multilevel Inverter Structures with Reduced Number of Switching Devices

2018 ◽  
Vol 11 (1) ◽  
pp. 144 ◽  
Author(s):  
M. H. Yatim ◽  
A. Ponniran ◽  
M. A. Zaini ◽  
M. S. Shaili ◽  
N. A. S. Ngamidun ◽  
...  
Keyword(s):  
Stress Reduction ◽  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Harmonic Distortion ◽  
Multilevel Inverter ◽  
Total Harmonic Distortion ◽  
Multilevel Structure ◽  
Distortion Reduction ◽  
Switching Devices

The purpose of this study is to analyze the operation and design of symmetrical and asymmetrical multilevel inverter structures with reduced number of switching devices. In this study, the term of conventional inverter is defined as a single cascaded inverter. Specifically, the inverter operates in three complete loops and only produces 2-level and 3-level of output voltages. Usually, cascaded structure suffers from the high total harmonic distortion. Thus, by considering multilevel structure of inverter, low total harmonic distortion reduction and voltage stress reduction on switching devices can be archived. Sinusoidal pulse width modulation and modified square pulse width modulation are used as modulation techniques in switching schemes of the designed multilevel inverters. The findings indicate that, the designed multilevel structure cause low total harmonics distortion at the output voltage. Furthermore, the asymmetrical structure is producing the same output voltage levels with reduced number of switching devices compared to the symmetrical structure is experimentally confirmed. The findings show that the total harmonic distortion for 7-level (symmetrical) and 9-level (asymmetrical) are 16.45% and 15.22%, respectively.

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