scholarly journals Reduced Number of Power Switches in Multi level Inverter Using SPWM Technique to Mitigate For SAG and SWELL

Author(s):  
N.Eashwaramma et al., N.Eashwaramma et al., ◽  
Keyword(s):  

The study of single phase Switched Capacitors Multi Level Inverter (MLI) is used with Switched Capacitor Converter (SCC) units. The SCC is used to increase the input DC voltage by connecting capacitor in string and shunt. This increassed DC link voltage is converted in to multilevel i.e. 49 level AC output. This SCMLI topology is used to reduce the number of switches, diodes, isolated dc power supply and Total Harmonic Distortion (THD). The SCMLI provides 49 level output voltage using 14 power switches and 3 isolated power supply. The performance of the SCMLI topology is confirmed by using MATLAB simulation result


2019 ◽  
Vol 28 (11) ◽  
pp. 1950194 ◽  
Author(s):  
Saikat Majumdar ◽  
Bidyut Mahato ◽  
Kartick Chandra Jana

A single-phase cascaded generalized doubling circuit-based multi-level inverter configuration is presented that can generate maximum number of output voltage levels by distributing the total asymmetrical input DC link voltage among the cells using minimum number of power switches. A cell consists of [Formula: see text] numbers of sub-cells each having two DC voltage sources connected in series along with a half-bridge circuit and a polarity reversal unit. Moreover, an optimum structure of novel proposed MLI is presented and well described in the paper. A laboratory prototype of proposed 15-level MLI is developed and the experimental results are found at par with the simulation results. The experimental results are captured for different modulation indices to show the effectiveness of the proposed MLI that can be used for Photovoltaic (PV) applications.


Author(s):  
Bolla Madhusudana Reddy ◽  
Y. V. Siva Reddy ◽  
M. Vijaya Kumar

<p><span lang="EN-US">This paper proposes a new optimal high level multilevel inverter with minimum number of components. This multi level inverter (MLI) is designed with series combination of basic units which can generate positive levels at output. DC source values applied for each basic unit is different with another. An H bridge is connected across proposed MLI for generating negative levels along with positive levels at output and that inverter considered as proposed high level optimal multilevel inverter. Single unit is responsible producing 21 levels. Therefore six units are connected in cascaded form to increase number of levels as 127 at output. Decrease in the number of power switches, driver circuits, and dc voltage sources are the improvement of the proposed MLI. Sinusoidal multiple pulse width modulation (SPWM) technique is implemented to produce pulses for turning ON switches according requirement. Low total harmonic distortion at output voltage or current production is major advantage of proposed module. The validations of proposed MLI results are verified through MATLAB/SIMULINK.</span></p>


2021 ◽  
Author(s):  
Ratul Das ◽  
Hanh-Phuc Le

<p>Gate driver circuits to ensure proper turn-on and turn-off for power switches are essential parts of a power converter design. They become even more important for multilevel converters where multiple switches are operated at active voltage domains. Recent favorable use of Gallium-Nitride (GaN) devices for power switches makes gate driving even more challenging as the switch performance and reliability are more sensitive to variations of the gate driving signals and power compared with traditional power MOSFETs. This paper discusses gate driving methods using a multi-level multi-inductor hybrid (MIH) converter as the demonstration prototype to address two key challenges in designing gate drivers: 1) providing level-shifted PWM signals to active voltage domains and 2) powering schemes for gate driver circuits. To solve the first challenge, an optimal use of available half-bridge drivers is devised to eliminate the need for separate signal isolator chips. This method was implemented and verified in a MIH converter prototype for 48-V Point-of-Load (PoL) applications using three different powering schemes for gate drivers, including isolated power modules, regulated supplies from switch blocking voltages, and cascaded bootstrap power rails with regulations. The gate driver techniques and powering schemes are compared experimentally in terms of performance to illustrate their benefits and trade-offs.</p>


2021 ◽  
Author(s):  
Ratul Das ◽  
Hanh-Phuc Le

<p>Gate driver circuits to ensure proper turn-on and turn-off for power switches are essential parts of a power converter design. They become even more important for multilevel converters where multiple switches are operated at active voltage domains. Recent favorable use of Gallium-Nitride (GaN) devices for power switches makes gate driving even more challenging as the switch performance and reliability are more sensitive to variations of the gate driving signals and power compared with traditional power MOSFETs. This paper discusses gate driving methods using a multi-level multi-inductor hybrid (MIH) converter as the demonstration prototype to address two key challenges in designing gate drivers: 1) providing level-shifted PWM signals to active voltage domains and 2) powering schemes for gate driver circuits. To solve the first challenge, an optimal use of available half-bridge drivers is devised to eliminate the need for separate signal isolator chips. This method was implemented and verified in a MIH converter prototype for 48-V Point-of-Load (PoL) applications using three different powering schemes for gate drivers, including isolated power modules, regulated supplies from switch blocking voltages, and cascaded bootstrap power rails with regulations. The gate driver techniques and powering schemes are compared experimentally in terms of performance to illustrate their benefits and trade-offs.</p>


Author(s):  
Ferdinand Keller ◽  
Tatjana Stadnitski ◽  
Jakob Nützel ◽  
Renate Schepker
Keyword(s):  

Zusammenfassung. Fragestellung: Über Veränderungen in der emotionalen Befindlichkeit von Jugendlichen während einer Suchttherapie ist wenig bekannt. Methode: Die Jugendlichen füllten wöchentlich einen entsprechenden Fragebogen aus, analog ihre Bezugsbetreuer eine parallelisierte Kurzfassung. Von 42 Jugendlichen liegen insgesamt 853 Bogen und von den Bezugsbetreuern 708 Bogen vor. Die Fragebogen wurden zunächst faktorenanalytisch hinsichtlich ihrer Dimensionalität ausgewertet, anschließend wurden gruppenbezogene Verlaufsanalysen (Multi-Level-Modelle) und Abhängigkeitsanalysen auf Einzelfallebene (Zeitreihenanalysen) durchgeführt. Ergebnisse: Im Jugendlichenfragebogen ergaben sich vier Faktoren: negative Befindlichkeit, Wertschätzung von Therapie/Betreuung, Motivation und Suchtdynamik. Die Übereinstimmung zwischen den Jugendlichen- und der (einfaktoriellen) Betreuereinschätzung fiel insgesamt niedrig bis mäßig aus, brachte aber auf Einzelfallebene differenziertere Ergebnisse. Im Verlauf nahmen die Werte auf allen vier Jugendlichenskalen ab. Einzig der Verlauf der Wertschätzung in der Eingewöhnungsphase war prädiktiv für den späteren Abbruch der Maßnahme: Bei den Abbrechern nahm die Wertschätzung ab, während sie bei den Beendern initial stieg. Schlussfolgerungen: Der bedeutsamste Faktor in Bezug auf die Therapiebeendigung suchtkranker Jugendlicher scheint die Wertschätzung von Therapie/Betreuung zu sein, während die Motivation jugendtypische Schwankungen aufweist. Der Suchtdynamik kam eine deutlich weniger bedeutende Rolle zu als allgemein angenommen. Programme in der Langzeittherapie sollten die Wertschätzung von Therapie/Betreuung künftig mehr fokussieren als die Suchtdynamik.


2017 ◽  
Author(s):  
Todd D. Smith ◽  
Mari-Amanda Dyal ◽  
Yongjia Pu ◽  
Stephanie Dickinson ◽  
David M. DeJoy

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