scholarly journals Contribution of Multilevel Inverters in Improving Electrical Energy Quality: Study and Analysis

2021 ◽  
Vol 23 (3) ◽  
pp. 255-263
Author(s):  
Saliha Rezini ◽  
Zin-Eddine Azzouz
Keyword(s):  
Output Voltage ◽  
Electrical Energy ◽  
Industrial Applications ◽  
Point Of View ◽  
Multilevel Inverters ◽  
Static Converters ◽  
Harmonic Pollution ◽  
Multi Level ◽  
Quality Study ◽  
Better Than

The work proposed in this paper concerns the study of harmonic pollution generated by static converters, particularly inverters, which largely contributes to the degradation of the supplied electrical energy quality. So, we studied in first the EMC of the conventional two-level inverter to highlight the harmful pollution of this kind of converter. We then looked at multi-level inverters to characterize their degree of pollution according to their number of levels in order to propose practical solutions for industrial applications. Thus, we considered three structures of multi-level inverters namely: a diode clamped inverter, a flying capacitor clamped inverter and a cascaded h-bridge inverter. At the end of this study, we retain that these three structures make it possible to obtain a waveform of the output voltage close to the sinusoidal form. The results of simulation obtained and compared to the STD international standard templates, also allowed us to conclude that among the three structures studied the cascaded h-bridge inverter is the most interesting from the electrical energy quality point of view. In addition, this converter has the advantage of owning a reduced number of switches which results in a weight and a cost, better than those of the other two studied inverters.

An Improved ANFIS with Aid of ALO Technique for THD Minimization of Multilevel Inverters

2018 ◽  
Vol 27 (12) ◽  
pp. 1850193 ◽  
Author(s):  
Roy Francis ◽  
D. Meganathan
Keyword(s):  
Output Voltage ◽  
Fitness Function ◽  
Harmonic Distortion ◽  
Objective Functions ◽  
Voltage Waveform ◽  
Swarm Optimization ◽  
Multilevel Inverters ◽  
Optimal Outcomes ◽  
Proposed Model ◽  
Multi Level

In this study, an artificial intelligent (AI) technique is proposed for minimizing the total harmonic distortion (THD) of the multi-level inverter (MLI). An AI technique is a mixture of an ALO and ANFIS, which controls the parameters of the inverter. The innovation of the proposed technique is improving the performance of the MLI, which is reducing the THD based on the output voltage waveform. Normally, the output voltage of the inverter is based on the switching angle of MLI. Then the proposed technique is utilized to optimize the switching angle and THD of the inverter. Here, the ALO is used to analyze the switching angle of the MLI with the aid of the fitness function. ANFIS is familiar with optimizing the switching angle from the ALO algorithm output. By the implementation of the proposed technique, decrease the value of THD in the MLI for gathering the performance of the system. Asymmetrical MLI is used in the proposed model and it wishes to separate DC supply to activate. For skilled activation, the optimal outcomes and the objective functions are well-definite and recognize their restriction similarly. The proposed technique was realized in MATLAB/Simulink platform and compared with the prevailing techniques such as particle swarm optimization (PSO)-ANFIS, genetic algorithm (GA)-Artificial Neural Networks (ANN) and ANN-ALO.

Neoteric Hybrid Multilevel Cascade Inverter Based on Low Switch Numbers Along with Low Voltage Stress: Design, Analysis, Verification

2017 ◽  
Vol 8 (1) ◽  
pp. 92
Author(s):  
Rasool Esmailzadeh ◽  
A. Ajami ◽  
M.R. Banaei
Keyword(s):  
Power Systems ◽  
Output Voltage ◽  
High Performance ◽  
High Efficiency ◽  
Low Voltage ◽  
Maximum Output ◽  
Dc Voltage ◽  
Multilevel Inverters ◽  
Voltage Stress ◽  
Multi Level

Abstract: With the purpose of rein in the high voltage of flexible power systems, renovation and amendment of multi-level structures aimed at acquisition of high quality voltage is certainly required. In this regard, robust topology must be occupied that encompass the maximum output voltage levels along with minimum of switch number, of course, with taking into account of Peak Inverse Voltage (PIV). In this paper, a neoteric high-performance multilevel cascaded inverter is suggested up to the problem of repetitive output levels to be unraveled and also number of output voltage levels to be maximized. It has been constructed by series-connected multilevel inverters blocks and three-level inverter. The simulation results along with experimental results extracted by manufactured prototype have transparently approved high efficiency of proposed inverter as well as its feasibility. Apart from above, new mathematical approach has been presented to calculate and define the DC voltage sources magnitudes in asymmetric converter.

scholarly journals A Simplified Control Strategy for an Enhanced Performance of Six Level Dual Inverter Fed Induction Motor Drive

2019 ◽  
Vol 8 (6) ◽  
pp. 1563-1567
Keyword(s):  
Induction Motor ◽  
Output Voltage ◽  
Simulation Analysis ◽  
Harmonic Distortion ◽  
Industrial Applications ◽  
Motor Drives ◽  
Motor Drive ◽  
Induction Motor Drive ◽  
Induction Motor Drives ◽  
Multilevel Inverters

Induction motor drives are employed in many of the industrial applications. The drives output depends on the inverter. Multilevel inverters are generally used in the induction motor drives but the dual inverter fed induction motor drive found more advantageous than the multilevel inverters. The performance of the Induction motor drive with open end winding for various levels of output voltage is presented in this paper. The inverter configuration implemented produces three-level, fourlevel, five-level and six-level in the output voltage waveform. The voltage and current harmonic distortion decreases as the number of levels are increased. The performance of the motor drive with the proposed inverter topology was found effective for sixth level. The simulation analysis of Induction motor drive with dual inverter is carried out in MATLAB-Simulink environment

scholarly journals Analysis of loss distribution of Conventional Boost, Z-source and Y-source Converters for wide power and voltage range

2017 ◽  
Vol 2 (1) ◽  
pp. 1 ◽  
Author(s):  
Brwene Salah Gadalla ◽  
Erik Schaltz ◽  
Yam Siwakoti ◽  
Frede Blaabjerg
Keyword(s):  
Output Voltage ◽  
Input Voltage ◽  
Industrial Applications ◽  
Point Of View ◽  
Small Range ◽  
Voltage Gain ◽  
Boost Converters ◽  
Voltage Range ◽  
High Voltage Gain ◽  
Simulation Results

Boost converters are needed in many applications which require the output voltage to be higher than the input voltage. Recently, boost type converters have been applied for industrial applications, and hence it has become an interesting topic of research. Many researchers proposed different impedance source converters with their unique advantages as having a high voltage gain in a small range of duty cycle ratio. However, the thermal behaviour of the semiconductor devices and passive elements in the impedance source converter is an important issue from a reliability point of view and it has not been investigated yet. Therefore, this paper presents a comparison between the conventional boost, the Z-source, and the Y-source converters based on a thermal evaluation of the semiconductors. In addition, the three topologies are also compared with respect to their efficiency. In this study the results show that the boost converter has higher efficiency than the Zsource and Y-source converter for these specific voltage gain of 2 and 4. The operational principle, mathematical derivations, simulation results and final comparisons are presented in this paper.

scholarly journals Enhancement of Power Quality for 15 Level Inverter using Phase Disposition-PWM Technique

2020 ◽  
Vol 6 (12) ◽  
pp. 1-6
Author(s):  
Richa Gupta
Keyword(s):  
Power Quality ◽  
Output Voltage ◽  
Harmonic Distortion ◽  
Industrial Applications ◽  
Multilevel Inverter ◽  
Half Wave ◽  
Wave Symmetry ◽  
Even Order ◽  
Multi Level

With consideration of use of solar, wind and other renewable energy source for industrial applications like electric vehicle drive, train traction and FACTS integration, which demand voltage levels in the range of kilo volts with high power quality, to achieve this high voltage level and high quality of power, a cascaded H-bridge multilevel inverter based topology capable of operating with low harmonic distortion is proposed in the paper. In order to attain low total harmonic distortion (THD), use of phase disposition-PWM technique is proposed in the paper. Giving due attention to both switch count and low THD, the output voltage levels of the multi-level inverter are set at 15 levels. Due to half wave symmetry the even order harmonics for proposed system become zero and the lower order harmonics reduces which is shown in tabular from. Due to reduced switch count and low THD the overall system become more efficient and effective. The effectiveness of the proposed control strategy has been verified using MATLAB simulations. Simulation is done for both symmetrical as well as asymmetrical multilevel inverter topology. It is observed that quality of the output voltage waveforms of the multi-level inverter (MLI) is as per the IEEE std 519 specifications. For symmetrical reduced switch fifteen level inverter the THD is 4.42% and for asymmetrical topology THD is 4.59% for the output voltage waveform.

Enzyme Promiscuous Activity: How to Define it and its Evolutionary Aspects

2020 ◽  
Vol 27 (5) ◽  
pp. 400-410
Author(s):  
Valentina De Luca ◽  
Luigi Mandrich
Keyword(s):  
Gene Evolution ◽  
Sequence Divergence ◽  
High Specificity ◽  
Industrial Applications ◽  
Point Of View ◽  
Enzyme Promiscuity ◽  
Primary Activity ◽  
Starting Point ◽  
Main Activity

: Enzymes are among the most studied biological molecules because better understanding enzymes structure and activity will shed more light on their biological processes and regulation; from a biotechnological point of view there are many examples of enzymes used with the aim to obtain new products and/or to make industrial processes less invasive towards the environment. Enzymes are known for their high specificity in the recognition of a substrate but considering the particular features of an increasing number of enzymes this is not completely true, in fact, many enzymes are active on different substrates: this ability is called enzyme promiscuity. Usually, promiscuous activities have significantly lower kinetic parameters than to that of primary activity, but they have a crucial role in gene evolution. It is accepted that gene duplication followed by sequence divergence is considered a key evolutionary mechanism to generate new enzyme functions. In this way, promiscuous activities are the starting point to increase a secondary activity in the main activity and then get a new enzyme. The primary activity can be lost or reduced to a promiscuous activity. In this review we describe the differences between substrate and enzyme promiscuity, and its rule in gene evolution. From a practical point of view the knowledge of promiscuity can facilitate the in vitro progress of proteins engineering, both for biomedical and industrial applications. In particular, we report cases regarding esterases, phosphotriesterases and cytochrome P450.

scholarly journals Suboptimal Disturbance Observer Design Using All Stabilizing Q Filter for Precise Tracking Control

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1434 ◽  
Author(s):  
Wonhee Kim ◽  
Sangmin Suh
Keyword(s):  
Design Method ◽  
Industrial Applications ◽  
Point Of View ◽  
Observer Design ◽  
Linear Matrix ◽  
External Disturbances ◽  
Closed Loop Systems ◽  
Control Target ◽  
The Stability ◽  
Unified Index

For several decades, disturbance observers (DOs) have been widely utilized to enhance tracking performance by reducing external disturbances in different industrial applications. However, although a DO is a verified control structure, a conventional DO does not guarantee stability. This paper proposes a stability-guaranteed design method, while maintaining the DO structure. The proposed design method uses a linear matrix inequality (LMI)-based H∞ control because the LMI-based control guarantees the stability of closed loop systems. However, applying the DO design to the LMI framework is not trivial because there are two control targets, whereas the standard LMI stabilizes a single control target. In this study, the problem is first resolved by building a single fictitious model because the two models are serial and can be considered as a single model from the Q-filter point of view. Using the proposed design framework, all-stabilizing Q filters are calculated. In addition, for the stability and robustness of the DO, two metrics are proposed to quantify the stability and robustness and combined into a single unified index to satisfy both metrics. Based on an application example, it is verified that the proposed method is effective, with a performance improvement of 10.8%.

ENHANCEMENT OF SCREEN FILM MAMMOGRAM UP TO A LEVEL OF DIGITAL MAMMOGRAM: EXPERIMENTAL ANALYSIS

2013 ◽  
Vol 13 (02) ◽  
pp. 1340004
Author(s):  
APARNA NARENDRA BHALE ◽  
MANISH RATNAKAR JOSHI
Keyword(s):  
Experimental Analysis ◽  
Breast Imaging ◽  
Point Of View ◽  
Quality Analysis ◽  
Digital Mammogram ◽  
Total Recovery ◽  
Clinical Observations ◽  
Opinion Score ◽  
Better Than

Breast cancer is one of the major causes of death among women. If a cancer can be detected early, the options of treatment and the chances of total recovery will increase. From a woman's point of view, the procedure practiced (compression of breasts to record an image) to obtain a digital mammogram (DM) is exactly the same that is used to obtain a screen film mammogram (SFM). The quality of DM is undoubtedly better than SFM. However, obtaining DM is costlier and very few institutions can afford DM machines. According to the National Cancer Institute 92% of breast imaging centers in India do not have digital mammography machines and they depend on the conventional SFM. Hence in this context, one should answer "Can SFM be enhanced up to a level of DM?" In this paper, we discuss our experimental analysis in this regard. We applied elementary image enhancement techniques to obtain enhanced SFM. We performed the quality analysis of DM and enhanced SFM using standard metrics like PSNR and RMSE on more than 350 mammograms. We also used mean opinion score (MOS) analysis to evaluate enhanced SFMs. The results showed that the clarity of processed SFM is as good as DM. Furthermore, we analyzed the extent of radiation exposed during SFM and DM. We presented our literally findings and clinical observations.

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