scholarly journals Comparative analysis of various multilevel inverter symmetrical topologies with minimum number of components

2018 ◽  
Vol 7 (1.8) ◽  
pp. 77
Author(s):  
Ali Qasim Hussein Algburi ◽  
P V. Ramana Rao

Multilevel inverters (MLI) are frequently used in different fields like, oil and gas sectors, installations of power supply, high power and medium voltage applications and in FACTS (flexible AC transmission system) devices to improve power quality. Lot of topologies has been developed in the literature regarding multilevel inverters such as diode clamped type, flying capacitor type and cascaded H-bridge type multilevel inverters. However, several challenges are being faced while implementing these topologies like more number of switches, more losses and cost. The optimized construction of multilevel inverter is to get more number of levels with less number of switches and low total harmonic distortion. In this paper, three different existing multilevel inverter topologies have been considered and analyzed for five level output voltage. A comparison table is given for number of switches, extra diodes and voltage sources. The total work is carried by using Matlab/simulink software and results are presented.

2013 ◽  
Vol 768 ◽  
pp. 231-237
Author(s):  
R. Seyezhai ◽  
K. Radha Sree ◽  
K. Sivapathi ◽  
V. Vardhaman

Multilevel inverters have been gaining immense popularity in high power applications such as Electric vehicles, Flexible AC Transmission Systems etc. This paper focuses on an asymmetric cascaded multilevel inverter employing the variable frequency carrier phase shifted PWM technique. The major advantage of this strategy is that it aids in balancing the switch utilization. The proposed strategy was found to have lower THD and switching losses when compared to the conventional strategies. The simulation was performed using MATLAB/Simulink and the results were verified experimentally.


2019 ◽  
Vol 9 (1) ◽  
pp. 3836-3845
Author(s):  
Y. Gopal ◽  
K. P. Panda ◽  
D. Birla ◽  
M. Lalwani

The problem of elimination of harmonics and the need of a large number of switches in multilevel inverters (MLIs) have been a hot topic of research over the last decades. In this paper, a new variant swarm optimization (SO) based selective harmonic elimination (SHE) technique is described to minimize harmonics in MLIs, which is a complex optimization problem involving non-linear transcendental equation. Optimum switching angles are calculated by the proposed algorithms considering minimum total harmonic distortion (THD) and the best results are taken for controlling the operation of MLIs. The performance of the proposed algorithm is compared with the genetic algorithm (GA). Conventional MLIs have some disadvantages such as the requirement of a large number of circuit components, complex control, and voltage balancing problems. A novel seven-level reduced switch multilevel inverter (RS MLI) is proposed in this paper to recoup the need of a large number of switches. Matlab/Simulink software is used for the simulation of two symmetrical topologies, i.e., a seven-level cascaded H-bridge multilevel inverter (CHB MLI) and a seven-level (RS MLI). Simulation results are validated by developing a prototype of both MLIs. The enhancement of the output voltage waveform confirms the effectiveness of the proposed SO SHE approach.


Multilevel inverters produced lot of interest in academia and industry as they are becoming feasible technology for number of applications. These are considered as the progressing power converter topologies. To generate a quality output waveform with minimum number of switches, reduced switch multilevel inverter topologies has come in focus. This paper introduces a modified symmetrical MLI with reduced component count thereby ensuring the minimum switching losses, reduced total harmonic distortion, Size and installation cost. By proper combination of switches it produces a staircase output waveform with low harmonic distortion. In this paper novel symmetrical inverter topology with reduced component count based on level shift phase opposition and disposition PWM (PODPWM) is proposed. The results are validated using MATLAB/SIMULINK.


2014 ◽  
Vol 977 ◽  
pp. 334-337
Author(s):  
Xi Lei ◽  
Gui Zhi Xu ◽  
Ke Zheng Xing

As a flexible AC transmission system equipment, controlled shunt reactor is becoming increasingly important in the grid with the development of EHV / UHV transmission systems. Since currently rated voltage of controlled shunt reactor has developed to 1100kV, as its capacity control system, or valve-control system, stability and reliability test is very important. In this paper, the test circuit and method for the valve-control system in the laboratory or the test station for combined adjustment test is put forward. By adjustment of power supply and the device parameter, the valve-control system can put the voltage and current of the device to be the same as the on-set operation. Actual test of the world's first 1100kV controlled shunt reactor valve-control system shows that, the test method in this paper is correct and feasible, and the objective of assessment can be achieved.


2017 ◽  
Vol 7 (1.5) ◽  
pp. 209
Author(s):  
B.Vijaya Krishna ◽  
B. Venkata Prashanth ◽  
P. Sujatha

Multilevel Inverters (MLI) have very good features when compared to Inverters. But using more switches in the conventional configuration will reduce its application in a wider range. For that reason a modified 7-level MLI Topology is presented. This new topology consists of less number of switches that can be reduced to the maximum extent and a separate gate trigger circuit. This will reduce the switching losses, reduce the size of the multilevel inverter, and cost of installation. This new topology can be used in Electrical drives and renewable energy applications. Performance of the new MLI is tested via. Total harmonic distortion. This construction structure of this multilevel inverter topology can also be increased for 9-level, 11-level and so on and simulated by the use of MATLAB/SIMULINK. A separate Carrier Based PWM Technique is used for the pulse generation in this configuration.


2014 ◽  
Vol 3 (3) ◽  
pp. 73-95 ◽  
Author(s):  
Marwa Shahin ◽  
Ebtisam Saied ◽  
M.A. Moustafa Hassan ◽  
Fahmy Bendary

The main subject of these paper deals with enhancing the steady-state and dynamics performance of the power grids by using new idea namely Advanced Flexible AC Transmission Systems based on Evolutionary Computing Methods. Control of the electric power system can be achieved by using the new trends as Particle Swarm Optimization applied to this subject to enhance the characteristics of controller performance. This paper studies and analyzes Advanced Flexible AC Transmission System to mitigate only one of power quality problems is voltage swell. The Advanced Flexible AC Transmission System, which will be used in this paper, is the most promising one, which known as Advanced Thyristor Controlled Series Reactors, and Advanced Static VAR Compensator were utilized in this research to mitigate the voltage swell aiming to reach. This paper focuses on the operation of the AFACTS device under turning off heavy load that may causes transformer damaged, as no research covers this problem by this technique. Particle Swarm Optimization is used to determine the value of series inductor connected to the Advanced Flexible AC Transmission System. The proposed algorithm formatting, deriving, coding and programming the network equations required to link AFACTS during steady-state and dynamic behaviors to the power systems tested on the IEEE 30 bus system as well as IEEE 14 bus system, and 9 bus system.


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