scholarly journals Design of new structure of multilevel inverter based on modified absolute sinusoidal PWM technique

Author(s):  
Asef A. Saleh ◽  
Rakan Khalil Antar ◽  
Harith Ahmed Al-Badrani

The advantage of multilevel inverters is to produce high output voltage values with distortion as minimum as possible. To reduce total harmonic distortion (THD) and get an output voltage with different step levels using less power electronics switching devices, 15-level inverter is designed in this paper. Single-phase 11-switches with zero-level (ZL) and none-zero-level (NZL) inverter based on modified absolute sinusoidal pulse width modulation (MASPWM) technique is designed, modelled and built by MATLAB/Simulink. Simulation results explained that, multilevel inverter with NZL gives distortion percent less than that with ZL voltage. The THD of the inverter output voltage and current of ZL are 4% and 1%, while with NZL is 3.6% and 0.84%, respectively. These results explain the effectiveness of the suggested power circuit and MASPWM controller to get the required voltage with low THD.

Multilevel inverters are widely used for high power and high voltage applications. The performance of multilevel inverters are superior to conventional two level inverters in terms of reduced total harmonic distortion, higher dc link voltages, lower electromagnetic interference and increased quality in the output voltage waveform. This paper presents a single phase hybrid eleven level multilevel inverter topology with reduced switch count to compensate the above mentioned disadvantages. This paper also presents various high switching frequency based multi carrier pulse width modulation strategies such as Phase Disposition PWM Strategy (PDPWM), Phase Opposition and Disposition PWM Strategy (PODPWM), Alternate Phase opposition Disposition PWM (APODPWM), Carrier Overlapping PWM (COPWM), Variable frequency carrier PWM (VFPWM), Third Harmonic Injection PWM (TFIPWM) applied to the proposed eleven level multilevel inverter and is analyzed for RL load. FFT analysis is carried out and total harmonic distortion, fundamental output voltage are calculated. Simulation is carried out in MATLAB/SMULINK.


Author(s):  
S. Usha ◽  
C. Subramani ◽  
A. Geetha

This paper deals with the design of cascaded 11 level H- bridge inverter. It includes a comparison between the 11 level H-bridge and T-bridge multilevel inverter. The cascaded inverter of higher level is a very effective and practical solution for reduction of total harmonic distortion (THD).These cascaded multilevel inverter can be used for higher voltage applications with more stability. As the level is increased the output waveform becomes more sinusoidal in nature. The inverter is designed using multicarrier sinusoidal pulse width modulation technique for generating triggering pulses for the semiconductor switches used in the device. Through this paper it will be proved that a cascaded multilevel H-bridge topology has higher efficiency than a T-bridge inverter, as whichever source input voltage is provided since input is equal to the output voltage. In T-bridge inverter, the output obtained is half of the applied input, so efficiency is just half as compared to H-bridge. The output waveform is distorted and has higher THD.  The simulation is performed using MATLAB /Simulink 2013 software.


2018 ◽  
Vol 7 (3.1) ◽  
pp. 42
Author(s):  
B Kandavel ◽  
G Uvaraj ◽  
M Manikandan

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.  


Author(s):  
Nunsavath Susheela

<p>The multilevel inverters have highly desirable characteristics in high power high voltage applications. The multilevel inverter was started first with diode clamped multilevel inverter. Later, various configurations have been came into existence for many applications. However the multilevel inverters have some demerits such as requiring higher number of components, PWM control method is complex and capacitor voltage balancing problem. The hybrid multilevel inverter presented in this paper has superior characteristics over conventional multilevel inverters. The hybrid multilevel inverter employs fewer components and less carrier signals when compared to conventional multilevel inverters. It consists of level generation and polarity generation stages which involves high frequency and low frequency switches. The complexity and overall cost for higher output voltage levels are greatly reduced. Implementation of single phase 7-level, 9-level and 11-level diode clamped multilevel inverter and hybrid multilevel inverter has been performed using sinusoidal pulse width modulation (SPWM) strategies i.e., phase disposition (PD), alternate phase opposition disposition (APOD). Also these techniques are compared in terms of total harmonic distortion (THD) for various modulation indices and observed to be greatly improved in case of hybrid inverter when compared to diode clamped inverter. The comparative study of performance for single phase diode clamped multilevel inverter and hybrid inverter is analyzed with different loads.  Simulation is performed using MATLAB/ SIMULINK. </p>


2019 ◽  
Vol 16 (2) ◽  
pp. 422-427
Author(s):  
S. Karthikeyan ◽  
K. Lakshmi ◽  
S. Sivaranjani ◽  
J. Karthika ◽  
T. Nandhakumar

Multilevel inverters are mainly used in high power and medium voltage applications to reduce the required voltage rating of the power semiconductor switching devices. Nowadays multilevel inverters are also preferred for various applications regardless of the power ratings because they can essentially realize lower harmonics with lower switching frequency and lower electromagnetic interference (EMI). However, it has some disadvantages such as increased number of components, complex Pulse Width Modulation control method, and voltage balancing problem. In this paper a new topology of cascaded multilevel inverter using reduced number of switches is introduced resulting in higher output voltage levels. There era five series connected H-bridges and the DC voltage is given in the ratio n0: n: n3:2n2:10n. The output voltage having 123 levels is obtained (61 positive voltage levels, 61 negative voltage levels and zero voltage levels). Reduced Total Harmonic Distortion (THD) makes them useful for electric vehicle, FACTS and has given option for various power applications. The proposed topology results in reduction of cost and has simplicity of control system. Therefore, the overall cost and complexity are greatly reduced particularly for higher output voltage levels.


2016 ◽  
Vol 78 (5-8) ◽  
Author(s):  
N.S.M. Nazar ◽  
S. Thanakodi ◽  
N.A. Othman ◽  
H.D.M. Hidzir ◽  
M.S. Mat

It has been accepted that conventional inverters have limitation dealing with high voltage and high power applications. Lately, multilevel inverters are popular for high power applications due to its improved harmonic profile and increased power ratings. There are various literatures regarding topology and control techniques of multilevel inverters. This paper presents the performance of two Flying Capacitor Multilevel Inverter (FCMI) topologies particularly a 3-level and 5-level multilevel inverters. Besides that, concept of the topologies and its modulation techniques were described. Sinusoidal pulse width modulation (SPWM) techniques were utilized in this paper as the topologies control strategy. Two control parameters, namely the amplitude modulation index, ma and the frequency modulation index, mfwere varied in order to control the output voltage of the inverters. The model and simulation study were carried out using Matlab/Simulink software. Analyses on the performance of the two topologies were based on the fundamental voltage, output voltage waveform, output harmonic spectrum and total harmonic distortion (THD). It’s found that the five level FCMI have shown better performance in terms of THD compared to the three level FCMI in all conditions of varied ma and mf. Based on the study also, five level FCMI shows a better voltage output waveform; close to a sinusoidal waveform compared to the three level FCMI.


2021 ◽  
Vol 309 ◽  
pp. 01120
Author(s):  
Sameera Shaik ◽  
Suresh Kumar Tummala ◽  
D Srinivasa Rao

Nowadays, the multilevel inverter has gained huge attention and has become more popularized in high voltage and high-power applications with low harmonics. As the number of output voltage increases, the harmonic content of the output voltage waveform decreases. In this paper, a comparison of cascaded H-bridge and cross-switched multilevel inverters for 7, 9, 15, 21 levels will be carried out. The different control techniques that will be used for carrying out comparisons are space vector pulse width modulation (SPVPWM), sinusoidal pulse width modulation (SPWM), and third harmonic injection pulse width modulation (THI-PWM) respectively. Here, the seven-level inverter is discussed mainly and can be extended to any number of levels.


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

<p class="Els-Abstract-text">A comparative analysis of three phase eleven level diode clamped multilevel inverter (DCMLI) and hybrid inverter is performed in this paper in which the later requires fewer carrier signals, less number of devices and gate drive circuits. The performance is evaluated using phase disposition (PD), alternate phase opposition disposition (APOD) and carrier overlapping (CO) sinusoidal pulse width modulation (SPWM) methods. The hybrid multilevel inverter has superior features over diode clamped multilevel inverters and is more efficient since the positive levels of the inverter that are generated  by high frequency switches (level generation part), are reversed by low frequency switches (polarity generation part) when the voltage polarity is required to be changed for negative polarity. Therefore, the overall cost and complexity of the hybrid inverter are greatly reduced particularly for higher inverter output voltage levels. Simulation is performed for three phase eleven level diode clamped multilevel inverter and hybrid multilevel inverter using MATLAB/Simulink for induction motor load and the total harmonic distortion is evaluated at different load torques.</p>


Author(s):  
P Yogini Dr. Sujatha Balaraman,

The prominence of Modular Multilevel Inverters (MMI) is rising owing their merits of simple mechanical construction and good voltage sharing for semiconductor devices. Mostly Multilevel Inverters use more than one source; however, the effective use of all the sources at all levels is rare. Conventional Multilevel Inverters will diminish the energy efficiency of the conversion system. When compared to conventional multilevel inverter, Modular Multilevel Inverter with a high numbers of voltage levels seem to be the most suitable because of the use of an isolated dc source. This paper explores a three-phase eleven level modular multilevel inverter with phase disposition pulse width modulation technique (PD-PWM) that can extract power from all the sources at all the levels. Besides, this paper develops a synchronous d-q reference frame controller to control the current of 11kV. When compared with Reduced Switch Count based Multilevel Inverter Series/Parallel switching topologies, the Modular Multilevel Inverter provides better Total Harmonic Distortion (THD) of output voltage and utilization factor.


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

The multilevel inverters are very popular in high power high voltage applications. However the multilevel inverters has some demerits such as requiring higher number of components, PWM control method is complex and capacitor voltage balancing problem. The hybrid multilevel inverter presented in this paper has superior characteristics over conventional multilevel inverters. The hybrid multilevel inverter employs fewer components and less carrier signals when compared to conventional multilevel inverters. It consists of level generation and polarity generation stages which involves high frequency and low frequency switches. The complexity and overall cost for higher output voltage levels are greatly reduced. Implementation of single phase 7-level, 9-level and 11-level hybrid multilevel inverter has been performed using sinusoidal pulse width modulation (SPWM) strategies i.e., phase disposition (PD), alternate phase opposition disposition (APOD) and carrier overlapping (CO). Also the three techniques are compared in terms of total harmonic distortion (THD) for various modulation indices and observed to be greatly improved when compared to conventional topologies. The performance of single phase eleven level hybrid inverter is analyzed for different loads.  Simulation is performed using MATLAB/ Simulink.


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