scholarly journals PRINCIPLES OF IMPROVEMENT OF MULTILEVEL AUTONOMOUS VOLTAGE INVERTERS

Author(s):  
I.V. Volkov ◽  
◽  
V.V. Golubev ◽  
V.I. Zozulev ◽  
◽  
...  

The article considers the properties of the most commonly used two-and multilevel inverter topologies used in systems for converting electricity from several primary power sources into the required high-quality output voltage for low-voltage networks and high-voltage consumers. However, a common disadvantage of most known multilevel converters is the increasing complexity of power structures, an increase in the number of primary power sources, power elements, and the cost of devices as the number of their voltage levels increases. Two schemes of alternative three-level autonomous voltage inverters with a high-frequency autotransformer with a midpoint and an example of constructing their digital control system are proposed. The analysis of their work on PSpice models in the OrCAD design system is carried out. The possibility of obtaining six voltage sublevels with fewer power elements and increased output voltage quality is shown, compared to the corresponding cascade multilevel inverters. The advantages and applications of autotransformer bridge voltage inverters in terms of energy and functionality compared to well-known multilevel inverters are presented. Ref. 8, fig. 7.

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.


2017 ◽  
Vol 100 (2) ◽  
pp. 733-739
Author(s):  
Abir Rehaoulia ◽  
Habib Rehaoulia ◽  
Farhat Fnaiech

Author(s):  
Rasool Esmailzadeh ◽  
A. Ajami ◽  
M.R. Banaei

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.


Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4406
Author(s):  
Yaoqiang Wang ◽  
Yisen Yuan ◽  
Gen Li ◽  
Tianjin Chen ◽  
Kewen Wang ◽  
...  

Conventional multilevel inverters have problems in terms of their complicated expansion and large number of devices. This paper proposes a modular expanded multilevel inverter, which can effectively simplify the expansion and reduce the number of devices. The proposed inverter can ensure the voltage balancing of the voltage-dividing capacitors. The cascading of the T-type switched capacitor module and the step-by-step charging method of the switched capacitors enable the inverter to achieve high output voltage levels and voltage gain. In addition, the inversion can be achieved without the H-bridge, which greatly reduces the total standing voltage of the switches. The nine-level inverter of the proposed topology can be realized with only ten switches, obtaining a voltage gain that is two times larger. The above merits were validated through theoretical analysis and experiments. The proposed inverter has good application prospects in medium- and low-voltage photovoltaic power generation.


Author(s):  
Thiyagarajan V. ◽  
Somasundaram P.

<span>Multilevel inverters offers less distortion and less electro-magnetic interference compared with other conventional inverters and hence, it can be used in many industrial and commercial applications.  This paper analyze the performance of the modified single phase seven level symmetrical inverter using minimum number of switches. The proposed topology consists of six switches and two dc sources, and produces seven level output voltage waveform during symmetric operation. The cost and size of the propsoed inverter minimum as it uses minimum number of components, The performance of the proposed multilevel inverter is analysed for different switching angles and the corresponding simulation results are presented. The simulation of the proposed inverter is carried out using MATLAB/Simulink software.</span>


2021 ◽  
Vol 10 (4) ◽  
pp. 1856-1863
Author(s):  
Mini P. Varghese ◽  
A. Manjunatha ◽  
T. V. Snehaprabha

Voltage regulator modules (VRM) need to have low output voltage ripple and tight efficiency to power advanced microprocessors. This paper explains a phase shedding technique to enhance efficiency and its impact on output voltage ripple. In this study, analysis was done on a 4-phase buck converter which is having an input voltage of 45-65 V and delivers an output of 9 V, 12A with a switching frequency of 200Khz. The phase shedding control scheme is suitable for applications such as power sources for programmable logic controllers, which is a part of SCADA systems, which requires a low voltage and high current power supply. Working of a multiphase buck converter with phase shedding is modelled and verified using Matlab/Simulink software. The simulation results show the effect of the phase shedding technique on efficiency in varying load conditions and the effect of an increase of the voltage ripple at the output.


2021 ◽  
Vol 309 ◽  
pp. 01073
Author(s):  
Sreekanth Reddy Kondreddy ◽  
B. Veeranna Sreenivasappa

A two-stage converter connects the input grid voltage to a pack of batteries with the voltage varying between 48-400 V, depending on the size and the range of the vehicle, with battery-operated electric and Plug-in Hybrid Electric Vehicles (PHEVs). This article offers a unique built-in converter that can interface with both high voltage (HV) and low voltage (LV) batteries. For all car architectures a universal charger that can accommodate this wide range of battery pack voltages is suitable. The novel integrated buck and boost converter (IBBC) is the proposed converter supplied using AC-DC driver at the front end mode. The main objective of this paper is to show a universal battery charger for an EV with a high power factor (PFC) and a small total harmonic distortion (THD) in addition to the high power density. A PFC converter is formed without any auxiliary circuit to balance the output voltage dependence of the battery against fluctuations in the ac grid input voltage, which in turn reduces the cost of additional circuit. A closed loop controller scheme is used to adjust for variations in the broad range output voltage and load. The proposed topology’s detailed operation is simulated using the MATLAB/Simulink software and achieved a THD of 1.18%.


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