scholarly journals Comparison of multiple modulation techniques for various topologies of multilevel converters for single phase AC motor drive

Author(s):  
Laith M. Akram Alsaqal ◽  
Ahmed M. T. Ibraheem Alnaib ◽  
Omar Talal Mahmood

There are various types of Multilevel Converters (MCs) in addition to various types of modulation techniques for these types of MCs; the challenges in selecting the best one of them with regard to the amount of the required of components, and its harmonics content. So, a comparison study among these types has been done in this paper. For comparison study, the simulation of seven level of two popular topologies of MCs: Neutral Point Clamped (NPC) converter, and Cascaded-MCs were carried out with Matlab/Simulink software program. These converters are used to drive a single phase capacitor start motor drive. Multicarrier modulation control techniques are used for controlling the MCs; these techniques involve two main type: Level Shifted Carrier (LSC), and Phase Shifted Carrier (PSC). The comparison is made with respect to the performance factors as, the amplitude of  the Total Harmonic Distortion (THD), and the DC-bus utilization performance which measured by Root Mean Square of the output voltage Vrms at variable modulation indices and variable carrier frequency. Based on simulation results it's found, that the cascaded-MC with PSC modulation method gives best results, in addition to the Alternative Phase Opposition Disposition APOD-LSC modulation technique (with even number of modulation frequency) generate the output voltage with a lower harmonic content compared with the other techniques.

2018 ◽  
Vol 7 (3) ◽  
pp. 1059
Author(s):  
Mustafa Fawzi Mohammed ◽  
Ali Husain Ahmad ◽  
AbdulRahim Thiab Humod

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.  


2018 ◽  
Vol 19 (2) ◽  
pp. 43-53
Author(s):  
Majdee Tohtayong ◽  
Sheroz Khan ◽  
MASHKURI BIN YAACOB ◽  
Siti Hajar Yusoff ◽  
NUR SHAHIDA BINTI MIDI ◽  
...  

ABSTRACT: This paper presents simulation results of the influence of wide range modulation index values ( ) in carrier-based PWM strategy for application in generating the stepped waveform. The waveform is tested for application in single-phase half-bridge modular multilevel converters (MMCs) topology. The results presented in this paper include a variation of the fundamental component (50 Hz) in the voltage output.  It also studies total harmonic distortion of the output voltage (THDv) and the output current (THDi) when the modulation index is changed over the linear-modulation region, 0 < < 1. It also explores the effect of a modulation index greater than 1. Moreover, different output voltage shapes, as a consequence of varied  on MMCs, are also illustrated for showing the effect of varying the value of on sub-module of MMCs. ABSTRAK: Kajian ini berkenaan tentang pengaruh simulasi terhadap pelbagai nilai indeks ( ) berasaskan strategi PWM bagi menghasilkan bentuk gelombang bertingkat. Bentuk gelombang ini diuji untuk aplikasi topologi MMCs. Keputusan menunjukkan variasi pada komponen asas (50Hz) pada voltan akhir. Keputusan menunjukkan jumlah penyelarasan harmonik voltan akhir (THDv) dan arus (THDv) apabila indeks modulasi telah ditukar pada had modulasi linear, 0 < < 1. Ia juga membincangkan tentang kesan indeks modulasi lebih daripada 1. Selain itu, bentuk voltan akhir yang berbeza mengikut perubahan nilai   pada MMCs juga dilampirkan bagi menunjukkan kesan perbezaan nilai    pada sub-modul MMCs.


2018 ◽  
Vol 24 (12) ◽  
pp. 45-59
Author(s):  
Omar Talal Mahmood Altaee ◽  
Ahmed M. T. Ibraheem Alnaib

The applications of Multilevel Converter (MLC) are increased because of the huge demand for clean power; especially these types of converters are compatible with the renewable energy sources. In addition, these new types of converters have the capability of high voltage and high power operation. A Nine-level converter in three modes of implementation; Diode Clamped-MLC (DC-MLC), Capacitor Clamped-MLC (CC-MLC), and the Modular Structured-MLC (MS-MLC) are analyzed and simulated in this paper. Various types of Multicarrier Modulation Techniques (MMTs) (Level shifted (LS), and Phase shifted (PS)) are used for operating the proposed Nine level - MLCs. Matlab/Simulink environment is used for the simulation, extracting, and analysis the results. Finally, a comparison is made between the results for all topologies that are implemented regarding to the criteria of the output voltage waveforms harmonic distortion factor, No. of the necessitated power components, and the complexity of each circuit. Based on simulation results, the MS-MLC is finer as compared to the other types of MLCs. It also observed that the MLCs (with three types) using Phase Opposition Disposition (POD) technique is performed better in terms of getting greater fundamental output voltage and lower THD% as compared to the other techniques.  


2018 ◽  
Vol 19 (2) ◽  
pp. 182-191 ◽  
Author(s):  
Md Sazzad Hossien Chowdhury ◽  
Md. Alal Hosen ◽  
MOHAMMAD YEAKUB ALI ◽  
AHMAD FARIS ISMAIL

ABSTRACT: This paper presents simulation results of the influence of wide range modulation index values ( ) in carrier-based PWM strategy for application in generating the stepped waveform. The waveform is tested for application in single-phase half-bridge modular multilevel converters (MMCs) topology. The results presented in this paper include a variation of the fundamental component (50 Hz) in the voltage output.  It also studies total harmonic distortion of the output voltage (THDv) and the output current (THDi) when the modulation index is changed over the linear-modulation region, 0 < < 1. It also explores the effect of a modulation index greater than 1. Moreover, different output voltage shapes, as a consequence of varied on MMCs, are also illustrated for showing the effect of varying the value of on sub-module of MMCs. ABSTRAK: Penulisan ini berkenan simulasi pengaruh pelbagai nilai indeks modulasi     ( ) dalam strategi PWM berasaskan aplikasi dalam menghasilkan bentuk gelombang yang bertingkat. Bentuk gelombang ini diuji untuk aplikasi dalam topologi MMCs. Penilaian dan hasil dari artikle ini termasuk variasi komponen asas (50 Hz) dalam voltan keluar. Ia juga meneliti jumlah penyelarasan harmonik voltan keluar (THDv) dan arus keluaran (THDi) apabila indeks modulasi ditukar dalam rantau modulasi linear, 0 < <1. Ia juga meneroka kesan indeks modulasi lebih daripada 1. Selain itu, bentuk voltan keluar yang berbeza sebagai akibat dari pelbagai  pada MMCs juga digambarkan untuk menunjukkan kesan berbeza-beza nilai  pada sub-modul MMCs.


Electronics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 154
Author(s):  
Wei Yao ◽  
Jiamin Cui ◽  
Wenxi Yao

This paper presents a novel digital control scheme for the regulation of single-phase voltage source pulse width modulation (PWM) inverters used in AC power sources. The proposed scheme adopts two deadbeat controllers to regulate the inner current loop and the outer voltage loop of the PWM inverter. For the overhead of digital processing, the change of duty of PWM lags one carrier period behind the sampling signal, which is modeled as a first-order lag unit in a discrete domain. Based on this precise modeling, the deadbeat controllers make the inverter get a fast dynamic response, so that the inverter’s output voltage is obtained with a very low total harmonic distortion (THD), even when the load is fluctuating. The parameter sensitivity of the deadbeat control was analyzed, which shows that the proposed deadbeat control system can operate stably when the LC filter’s parameters vary within the range allowed. The experimental results of a 2kW inverter prototype show that the THD of the output voltage is less than 3% under resistive and rectifier loads, which verifies the feasibility of the proposed scheme. An additional advantage of the proposed scheme is that the parameter design of the controller can be fully programmed without the experience of a designer.


2015 ◽  
Vol 793 ◽  
pp. 167-171
Author(s):  
Mohd Aizuddin Yusof ◽  
Yee Chyan Tan ◽  
M. Othman ◽  
S.S. Lee ◽  
M.A. Roslan ◽  
...  

Multilevel inverters are one of the preferred inverter choices for solar photovoltaic (PV) applications. While these inverters are capable of producing AC staircase output voltage waveform, the total harmonic distortion (THD) of the output voltage waveform can become worse if the switching angle of each voltage level is not carefully chosen. In this paper, four switching angle arrangement techniques are presented and the switching angles generated by these techniques are applied to a new single-phase boost multilevel (SPBM) inverter. The performance of 3-, 5-, 7-, 9-and 11-level SPBM inverter having four different sets of switching angles derived using the aforementioned techniques have been evaluated and compared using PSIM software. Simulation results show that one of the techniques is able to produce an output voltage waveform with the lowest THD, whilst the other generates an output voltage waveform with the highest fundamental voltage component.


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):  
Hassan Salman Hamad

<span>Researchers<strong> </strong>have found interest in the multilevel inverters (MLI) owing to the low total harmonic distortion (THD) associated with their output voltage, as well as their low electromagnetic interference (EMI). The MLI represents an effective and feasible solution for enhancing power demand and minimizing AC waveforms’ harmonics as they generate a preferred level of output voltage as inputs from varying levels of DC voltages. In this paper, the performance of a seven-level cascaded H-bridge MLI with an asymmetrical number of power switches was evaluated. The simulation performance is shown to validate the operating principle of the single-phase cascaded H-bridge inverter. To control the MLI, a pulse width modulation approach was utilized. The operating principle of the MLI was verified via simulation using PSIM software.</span>


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