Comparative Study of Three level and Five level Inverter

International Journal on Electrical Engineering and Informatics, 2017

This paper discusses the difference between the three fundamental types of multilevel inverter (MLI) topologies, which are the neutral-point-clamped, the flying capacitors and the cascaded H-bridges. The sinusoidal pulse width modulation technique was used to simulate the output voltages and currents of the MLI inverters. The total harmonic distortion (THD) was estimated for each topology and each voltage level. Moreover, the simulation results indicate that the cascaded structure exhibited a lower THD value even when increasing the number of the output voltage. Furthermore, a new key parameter was defined as cost efficiency factor and used to compare the three topologies. Evaluation results of this factor indicate that the cascaded structure was the most advantages as it reduces stress effect on the inverter switches by eliminating the power diodes and capacitors.

2015 International Conference on Electrical, Electronics, Signals, Communication and Optimization (EESCO), 2015

In a real field, there are so many limitations in extracting power from renewable energy resources. To fulfil the power demand and scarcity of power, we have to improve the power extracting methods. Multilevel inverter is widely used to extract power from solar cells. It synthesizes the desired ac output from several dc sources.This paper presents a comparative analysis of different cascade H-Bridge multilevel inverter topology in which a low switching frequency is used for taking up the advantages of the low frequency, such as low thermal stress and high conversion efficiency. The inverter is operated on fundamental frequency switching strategy. The present topologies provide high quality output power due to its more output levels, low thermal stress and high conversion efficiency. This characteristic allowsachieving high-quality output voltages and output currents and also immense availability because of their intrinsic switches redundancy.This paper represents the comparative analysis in terms of THD and FFT of different level topologies. The different Multi level Inverter Topologies are simulated in PSIM.

This paper proposed novel multilevel inverter with low number of switches. Multilevel inverters are applicable for high power purpose in industries which become very popular. When compared to two level inverters these multilevel inverters produces good quality of output wave from. In such a way that, at first new proposed topology which as sub multilevel inverter is designed after that cascaded connection of sub multi level inverters called as novel cascaded multilevel inverter is proposed. This proposed novel cascaded multilevel inverter uses less number of switching devices. Separate attention optimal structure has been achieved by considering in different aspects such as number of switching devices, number of dc voltage sources and standing voltages on switching devices. This proposed novel cascaded multilevel inverter analyzed in symmetric and asymmetric forms of topologies which were compared with other multilevel inverter topologies suppose normal H bridge multilevel inverter by considering number components such as number of switches & IGBTs etc. The validity of proposed multilevel inverter verified with computer simulation. asymmetric; high quality wave form.

In the last few years, the necessity of increasing the power quality enhancement in industry has sustained the continuous development of multilevel- inverters due to high efficiency with low switching frequency control method. The inverter is a semiconductor device which is used to convert the fixed DC voltage into symmetrical AC voltage without changing the magnitude. To improve the power quality (AC) from the inverter output by performing the power conversion in small voltage steps resulted in lower harmonics. The output voltage on the AC side can take several discrete levels of equal magnitude. The harmonic content of this output voltage waveform is greatly reduced, if compared with a two level voltage wave form (inverter). This method is called as multilevel inverter. Multi-level power inverters employ power semiconductor switches in the inverter to select one or more of multi dc voltage source to create staircase voltage waveform at the inverter output. In the multilevel inverter the output voltage is in the form of stepped waveform, so that the harmonics will be reduced and thereby increase the voltage gain and power quality of the output AC from the MLI.

Simulation of cascaded H-Bridge multilevel inverter for different levels is presented in this paper. Higher power levels can be obtained from utilizing lower voltage levels which was the theory proposed over thirty years ago. Conversion of DC to AC having desired output voltage and frequency can be obtained from two types of inverters which are single level and multilevel inverter (MLI). Amongst all MLI topologies Cascaded H-Bridge type is take into consideration for this paper. Advantages of MLI include minimum harmonic distortion, reduced EMI and it can be operated on different voltage levels [1]. Here IGBT's are taken as switches which are to be controlled by providing proper switching angles that is generated by any optimization techniques. Here genetic algorithm is taken as the optimization method and switching angles are derived. Simulation of 5-level, 7-level, 11-level cascaded multilevel inverter is presented here and the output waveforms were observed using MATLAB.

In this paper, a modular cascaded H-bridge multilevel inverter for single-phase and three-phase renewable applications has been described. HCMMLI (Hybrid Cascaded Modular Multilevel Inverter) is one of the useful power electronic interface strategy for PV system The primary operation of single phase module and the cascaded hybrid inverter has been explained in this paper. The operation of symmetrical mode has been analyzed. The Nearest Level Control method of multilevel inverter topology is discussed. With this topology, less number of switches could be used which reduces switching losses and harmonic distortion. The size and cost of the system is reduced with the reduced power switches. In this paper, the main focus is on utilization of above discussed topology for several H Bridge configuration with equal and unequal magnitude of DC source. This configuration are considered to be symmetrical and asymmetrical. Here, in order to find an optimum arrangement with high quality output voltage, the comparison of symmetrical, binary asymmetrical and trinary asymmetrical topologies are analyzed.

Energies

A three-phase multilevel inverter topology for use in various applications is proposed. The present topology introduces a combination of a cascaded H-bridge multilevel inverter with a cascaded three-phase voltage source inverter (three-phase triple voltage source inverter (TVSI)). This combination will increase the number of voltage levels generated when using fewer components compared with the conventional multilevel inverter topologies for the same voltage levels generated. The other advantage gained from the proposed configuration is the assurance of a continuous power supply to the grid in case of failure in one part of the proposed configuration. In addition, the voltage stresses on switches are reduced by half compared if each part in the proposed topology is working independently. The comparison of the proposed topology with some conventional multilevel inverter topologies is presented. The proposed topology is built in the SIMULINK environment and is simulated under various loads in addition to being connected to the grid. Phase-shifted pulse width modulation technique is used to generate the required switching pulses to drive the switches of the proposed topology. The inverter is experimentally implemented in the lab, and the switching pulses are generated with the help of MicroLabBox produced by dSPACE (digital signal processing and control engineering) company. The simulation and experimental results and their comparisons are presented to verify the proposed topology's effectiveness and reliability.

There are many limitations in extracting power from renewable energy resources. To minimize the power demand and scarcity we have to improve the power extracting methods. Multilevel inverter is used to extract power from solar cells. It synthesizes the desired ac output waveform from several dc sources. This paper focuses on improving the efficiency of the multilevel inverter and quality of output voltage waveform. Seven level reduced switches topology has been implemented with only seven switches. Fundamental Switching scheme and Selective Harmonics Elimination were implemented to reduce the Total Harmonics Distortion (THD) value. Selective Harmonics Elimination Stepped Waveform (SHESW) method is implemented to eliminate the lower order harmonics. Fundamental switching scheme is used to control the power electronics switches in the inverter. The proposed topology is suitable for any number of levels. The harmonic reduction is achieved by selecting appropriate switching angles. It shows hope to reduce initial cost and complexity hence it is apt for industrial applications. In this paper third and fifth level harmonics have been eliminated. Simulation work is done using the MATLAB software and experimental results have been presented to validate the theory.

It is not possible to connect power semiconductor switch directly at medium and high voltage level. This introduced a new unit of inverters as a result of applying higher voltage levels, which can be called as multilevel inverters. Multilevel inverters are synthesizing close to sinusoidal voltage from some levels of DC voltages. Multilevel inverters synthesize the stair – case voltage waveform with some lower harmonic content. The output voltages from inverters have reduced harmonic distortions and good quality of waveforms. Because when used this inverter THD content in voltage waveform is very significant it affects the performance of load. This article deals with study and analysis of a single phase multilevel inverter with various levels. By using Matlab different multilevel inverter models are simulated and get an output voltage waveform and THD.

The conventional two level inverter has many limitations for high voltage and high power application. Multilevel inverter becomes very popular for high voltage and high power application. The multilevel began with the three level converters. The elementary concept of a multilevel converter to achieve higher power to use a series of power semiconductor switches with several lower voltage dc source to perform the power conversion by synthesizing a staircase voltage waveform. However, the output voltage is smoother with a three level converter, in which the output voltage has three possible values. This results in smaller harmonics, but on the other hand it has more components and is more complex to control. In this paper, study of different three level inverter topologies and SPWM technique is explain and SPWM technique has been applied to formulate the switching pattern for three level and five level H-Bridge inverter that minimize the harmonic distortion at the inverter output. This paper deals with comparison of simulation results of three level and five level H-Bridge inverter and implementation of single leg of three level H-Bridge inverter.