scholarly journals THD Reduction in Multi-Level Inverters based on Multicarrier Pulse Width Modulation Technique

t Due to the advent of technology, electronic equipments are much more sensitive to harmonic and its analysis play an important role whereby reducing the distortion due to harmonics needs attention. To meet the requirements of the industries, harmonic free-high rating power sources are in high demand. Total Harmonic Distortion (THD) is an indicator of AC voltage source quality. In case of inverters, one such way to reduce THD would be the use of Pulse Width Modulation (PWM). The existing methods mainly use the low frequency pulse width modulation techniques for the switching. Control methods employing high frequency switching techniques held in controlling THD with proper application of filters. This paper analyses THD in multilevel inverters using multicarrier PWM technique with five pulse width modulation technique through MATLAB simulations. Finally, a comparison is done to find the less harmonic generated PWM method using fewerfilters.

2016 ◽  
Vol 9 (10) ◽  
pp. 2139-2146 ◽  
Author(s):  
Hung‐Liang Cheng ◽  
Yong‐Nong Chang ◽  
Chun‐An Cheng ◽  
Chien‐Hsuan Chang ◽  
Yu‐Hung Lin

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 263
Author(s):  
Manyuan Ye ◽  
Wei Ren ◽  
Qiwen Wei ◽  
Guizhi Song ◽  
Zhilin Miao

Asymmetric Cascaded H-bridge (ACHB) level inverters can output more voltage waveforms with fewer cascaded units while ensuring the quality of output voltage waveforms, so they have attracted more and more attention. Taking the topology of Type-III asymmetric CHB multilevel inverters as the research object, a Modified Hybrid Frequency Pulse Width Modulation (MHF-PWM) strategy is proposed in this paper. This modulation strategy overcomes the local overshoot of low-voltage unit in the presence of traditional Hybrid Frequency Pulse Width Modulation (HF-PWM), thus completely eliminating the low frequency harmonics in the output voltage waveform of Type-III ACHB nine-level inverters, and the Total Harmonic Distortion (THD) of output line voltage of the modulation strategy is lower than that of PS-PWM strategy in the whole modulation degree, which effectively improves the quality waveform of the output line voltage. At the same time, the strategy can also improve the problems of current backflow and energy feedback caused by the high-voltage unit pouring current to the low-voltage unit, thereby reducing the imbalance of the output power of the high-voltage and low-voltage units. Finally, the Matlab/Simulink simulation model and experimental platform are established to verify the validity and practicality of the modulation strategy.


2020 ◽  
Vol 8 (5) ◽  
pp. 5180-5185

Paper Setup must be in A4 size with Margin: Top In the present paper multi carrier sinusoidal modulation technique which is an efficient method of producing control signals is used for a symmetrical inverter with several levels in cascade H Bridge is discussed. The Cascaded H-Bridge performance output levels depend on the DC voltage sources used at the input side. With the help of two DC voltage sources, five level output can be obtained whereas three sources gives levels of seven in output voltage. In this paper, multi-carrier SPWM switching is obtained for switching of multilevel inverter based switches. Two signals are used in this switching method, among which one of the signals is reference which is a low frequency sinusoidal signal and the one is a carrier signal. In case of sinusoidal PWM method of modulation technique, the reference signal is a sinusoidal one and triangular signal can be used as a carrier signal. These types of inverters have the ability to generate inverted output voltage with an efficient harmonic spectrum and reliable output results. This document provides switching signal for H-bridge inverter structure which can improve harmonic performance. The 5-level multilevel inverter is simulated for traditional carrier-based pulse-width modulation (PWM) phase change carrier techniques. The total harmonic performance of the output voltages is analyzed for the two PWM control methods. The performance of the symmetrical PWM CHB is simulated using MATLAB-SIMULINK model. Model results show that THD can be minimized to a limit with level shifted modulation method of the sinusoidal pulse width. The results from the simulations show that the quality of the waveform of the output voltage improves with less loss and with a lower THD.


Author(s):  
Sony Prakarsa Putra ◽  
Zulwisli Zulwisli

This study aims to create a PWM inverter that can drive the Brushless Unidirectional Flow Machine (MASTS). PWM inverters are intended to correct deficiencies in six-step inverters. Inverter is a circuit that is used to convert a DC voltage source into an AC voltage with a certain frequency. The use of inverters is found in electric vehicles. The system often used to control an inverter is a Pulse Width Modulation (PWM) based control, where pulse width is used to regulate speed. The inverter is tested using 3 pairs of mosfets as a switch to control the three-phase output of the inverter. In the inverter, PWM is used to adjust the width of the frequency pulse that will be given to the mosfet. This research used 3 variations of duty cycle 30%, 60%, 90% to determine the effect of MASTS speed on PWM by using a PWM inverter. The results of this study the speed of MASTS can be influenced by changes in duty cycle, with increasing value of the duty cycle, the faster the speed of MASTS, and vice versa. Keywords:Mosfet, Sensor Hall, MASTS, PWM, Inverter.


Author(s):  
N. Susheela ◽  
P. Satish Kumar

<p>The popularity of multilevel inverters have increasing over the years in various applications without use of a transformer and has many benefits. This work presents the performance and comparative analysis of single phase diode clamped multilevel inverter and a hybrid inverter with reduced number of components. As there are some drawbacks of diode clamped multilevel inverter such as requiring higher number of components, PWM control method is complex and capacitor voltage balancing problem, an implementation of hybrid inverter that requires fewer components and less carrier signals when compared to conventional multilevel inverters is discussed. The performance of single phase diode clamped multilevel inverter and hybrid multilevel inverter for seven, nine and eleven levels is performed using phase disposition, alternate phase opposition disposition sinusoidal pulse width modulation techniques. Both the multilevel inverter are implemented for the above mentioned multicarrier based Pulse Width Modulation methods for R and R-L loads.  The total harmonic distortion is evaluated at various modulation indices. The analysis of the multilevel inverters is done by simulation in matlab / simulink environment.</p>


Author(s):  
Adireddy Ramesh, ◽  
O. Chandra Sekhar ◽  
M. Siva Kumar

<p>Penetration of multilevel inverters (MLI) in to high power and medium voltage application has been increasing because of its advantages. The conventional two levels inverter has high harmonic distortion which gives poor power quality. Lot of topologies has been developed to overcome the drawbacks of a two level inverter. These topologies include more number of switching devices which increases the design complexity and cost. The optimum design of inverter requires less number of switches with better quality in waveform. In this paper, a symmetrical five level and seven levels inverter configuration with simplified pulse width modulation technique is proposed. This proposed inverter requires less switches, less protection circuits along with low cost and size. The analysis of the inverter circuits is done by using Matlab/Simulink software. The synthesized staircase wave form is shown and total harmonic distortion (THD) is also measured.</p>


2021 ◽  
Author(s):  
Bolisetti Kavya Santhoshi ◽  
Kuppusamy Mohanasundaram ◽  
Vishnu Kumar Kaliappan ◽  
Ravishankar Sathyamurthy

Abstract The work proposed in this paper focuses on providing an effective solution to shortage of power in rural areas with an effective technique implemented in an economically feasible way. The traditional Inverters used for either residential or commercial purposes consume electrical energy from the grid to fulfill the charging and discharging of the battery, which may lead to overloading. The shortcomings of the traditional inverters such as Non-Renewable nature of power sources, increased cost of manufacturing, and multi-stage conversion complexity, are considered by the researchers for improvement. As a result, an attempt has been made to provide a cost effective renewable energy system with single stage topology for AC power applications. Single stage power conversion with allowed shoot through state is used here to avoid additional components and reduce the switching losses. Unlike the traditional inverters, the Quasi Impedance Source Inverter that is brought forward can be utilized as a Standalone system or a capable backup at the time of power outages. Sinusoidal pulse width modulation (SPWM) is applied to attain reduced harmonics which are measured by observing the harmonic pattern in Total Harmonic Distortion (THD) curve. The lab results obtained through MATLAB simulation confirm the noteworthy diminution of THD level in the proposed system compared to the reported one. Usage of Photovoltaic (PV) Panel to tap energy with reduced stochastic fluctuations due to high filtering capacity of the proposed circuit, eliminating the need of additional filters, is the uniqueness of this technique.


Author(s):  
N. Murali ◽  
V. Balaji

<span>This paper presents the performance enhancement of capacitor run induction motor by pulse width modulated AC chopper.The phase angle control faces severe shortfall in the performance improvement for larger triggering angles. In this paper the comparison of phase angle control and sinusoidal pulse width modulation technique is encountered for effective speed control of single phase capacitor run induction motor. The necessary parameters are taken into considerations are higher efficiency, lesser total harmonic distortion and high input power factor. The results are compared by using the simulations using matlab Simulink environment. The validation of result in hardware is implemented using Field programmable gate array for sinusoidal pulse width modulation technique.</span>


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