scholarly journals Theoretical Analysis of LC Filter to Three Level Diode Clamped Inverters in Low/Medium Voltage Applications

2020 ◽  
Vol 814 ◽  
pp. 012037
Author(s):  
Santoshkumar M. Hunachal ◽  
Bhagyraj Chodankar ◽  
Rahul Salgonkar ◽  
Durvesh Nakhwa
Keyword(s):  
Theoretical Analysis ◽  
Medium Voltage ◽  
Lc Filter

scholarly journals Design and implementation of multilevel non-isolated DC-DC converter for variable DC voltage source

2021 ◽  
Vol 12 (2) ◽  
pp. 994
Author(s):  
Ali Ahmed Adam Ismail ◽  
A. Elnady
Keyword(s):  
Power Converter ◽  
Buck Converter ◽  
Voltage Source ◽  
Stable Operation ◽  
Multilevel Converter ◽  
Medium Voltage ◽  
Voltage Stress ◽  
Filter Size ◽  
Converter Topology ◽  
Lc Filter

<span lang="EN-US">In this paper, a non-isolated multi-level DC-DC (MLDC-DC) smooth buck converter with the LC filter is designed and analyzed. The presented topology can be used in low or medium voltage levels in several applications that use DC storage elements. The use of the proposed multilevel converter topology reduces the voltage stress across the power converter switching elements and facilitates the voltage rating of the switches. The designed LC filter for the multilevel converter is characterized by a small inductor size, which reduces the traditional bulky inductor used in the output of the traditional DC-DC converter. The reduction in the filter size is proportional to the number of the connected voltage sources, it works effectively to reduce ripple in the load currents, and it increases the voltage gain. The intensive analysis of the converter system and the experimental results show a stable operation of the proposed converter with precise output voltage.</span>

scholarly journals Multilevel neutral point clamped/H-bridge inverters with sinusoidal pulse width modulation

2021 ◽  
Author(s):  
Arifur Rahman Shohel
Keyword(s):  
Computer Simulation ◽  
Theoretical Analysis ◽  
High Power ◽  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Neutral Point ◽  
Medium Voltage ◽  
Modulation Technique ◽  
Sinusoidal Pulse Width Modulation

This project focuses on the topology of multilevel neutral point clamped (NPC)/H-bridge inverters and their modified modulation technique for high-power (megawatts) medium voltage (typically 6000 v) applications. A sinusodial pulse width in-phase disposition modulation is proposed for five-level NPC/H-bridge inverters. The inverter achieves good harmonic performance and low dv/dt in its output voltage waveforms in comparison to the conventional three-level NPC inverter. A seven-level NPC/H-bridge topology and its sinusodial pulse width in-phase disposition modulation are also proposed and investigated, which has better performance than the five-level inverters. Theoretical analysis and computer simulation are carried out for the proposed inverter topologies and algorithms. The output voltage waveforms and harmonic performance are verified by experiments on a five-level NPC/H-bridge inverters.

scholarly journals New bidirectional step-up DC-DC converter derived from buck- boost DC-DC converter

2021 ◽  
Vol 12 (3) ◽  
pp. 1699
Author(s):  
Ridha D. N. Aditama ◽  
Naqita Ramadhani ◽  
Jihad Furqani ◽  
Arwindra Rizqiawan ◽  
Pekik Argo Dahono
Keyword(s):  
Theoretical Analysis ◽  
Laboratory Experiment ◽  
Cost Efficiency ◽  
Output Voltage ◽  
Voltage Drops ◽  
Lc Filter ◽  
Filter Capacitor ◽  
Switching Devices

<span lang="EN-US">This paper proposes a new bidirectional step-up DC-DC converter, namely modified buck-boost DC-DC converter. The proposed DC-DC converter was derived from the conventional buck-boost DC-DC converter. Output voltage expression of the proposed converter was derived by considering the voltage drops across inductors and switching devices. The results have shown that with the same parameter of input LC filter, proposed DC-DC converter has lower conduction losses. Moreover, the proposed DC-DC converter has lower rated voltage of filter capacitor than the conventional boost DC-DC converter which lead to cost efficiency. Finally, a scaled-down prototype of laboratory experiment was used to verify its theoretical analysis.</span>

scholarly journals Topology and Control Strategy of PV MVDC Grid-Connected Converter with LVRT Capability

2021 ◽  
Vol 11 (6) ◽  
pp. 2739
Author(s):  
Huan Wang ◽  
Yu Zhou ◽  
Xinke Huang ◽  
Yibo Wang ◽  
Honghua Xu
Keyword(s):  
Control Strategy ◽  
Control Method ◽  
Low Voltage ◽  
Current Control ◽  
Medium Voltage ◽  
Low Voltage Ride Through ◽  
Feedback Capacitor ◽  
Lc Filter ◽  
And Control ◽  
Medium Voltage Dc

This paper proposes an isolated buck-boost topology and control strategy for the photovoltaic (PV) medium-voltage DC (MVDC) converter with low-voltage ride through (LVRT) capability. The proposed isolated buck-boost topology operates on either boost or buck mode by only controlling the active semiconductors on the low-voltage side. Based on this topology, medium-voltage (MV) dc–dc module is able to be developed to reduce the number of modules and increase the power density in the converter, which corresponds to the first contribution. As another contribution, a LVRT method based on an LC filter for MVDC converter is proposed without additional circuit and a feedback capacitor current control method for the isolated buck-boost converter is proposed to solve the instability problem caused by the resonance spike of the LC filter. Five kV/50 kW SiC-based dc–dc modules and ±10 kV/200 kW PV MVDC converters were developed. Experiments of the converter for MVDC system in the normal and LVRT conditions are presented. The experimental results verify the effectiveness of the proposed topology and control strategy.

scholarly journals Multi-Port DC-DC and DC-AC Converters for Large-Scale Integration of Renewable Power Generation

2020 ◽  
Vol 12 (20) ◽  
pp. 8440
Author(s):  
Fahad Alsokhiry ◽  
Grain Philip Adam
Keyword(s):  
Theoretical Analysis ◽  
High Voltage ◽  
Direct Current ◽  
Power Flow ◽  
Experimental Results ◽  
Normal Operation ◽  
Medium Voltage ◽  
Renewable Power ◽  
Dc Fault ◽  
Wide Range

Numerous research studies on high capacity DC-DC converters have been put forward in recent years, targeting multi-terminal medium-voltage direct current (MVDC) and high-voltage direct current (HVDC) systems, in which renewable power plants can be integrated at both medium-voltage (MV) and high-voltage (HV) DC and AC terminals; hence, leading to complex hybrid AC-DC systems. Multi-port converters (MPCs) offer the means to promote and accelerate renewable energy and smart grids applications due to their increased control flexibilities. In this paper, a family of MPCs is proposed in order to act as a hybrid hub at critical nodes of complex multi-terminal MVDC and HVDC grids. The proposed MPCs provide several controllable DC voltages from constant or variable DC or AC voltage sources. The theoretical analysis and operation scenarios of the proposed MPC are discussed and validated with the aid of MATLAB-SIMULINK simulations, and further corroborated using experimental results from scale down prototype. Theoretical analysis and discussions, quantitative simulations, and experimental results show that the MPCs offer high degree of control flexibilities during normal operation, including the capacity to reroute active or DC power flow between any arbitrary AC and DC terminals, and through a particular sub-converter with sufficient precision. Critical discussions of the experimental results conclude that the DC fault responses of the MPCs vary with the topology of the converter adopted in the sub-converters. It has been established that a DC fault at high-voltage DC terminal exposes sub-converters 1 and 2 to extremely high currents; therefore, converters with DC fault current control capability are required to decouple the healthy sub-converters from the faulted one and their respective fault dynamics. On the other hand, a DC fault at the low-voltage DC terminal exposes the healthy upper sub-converter to excessive voltage stresses; therefore, sub-converters with bipolar cells, which possess the capacity for controlled operation with variable and reduced DC voltage over wide range are required. In both fault causes, continued operation without interruption to power flow during DC fault is not possible due to excessive over-current or over-voltage during fault period; however, it is possible to minimize the interruption. The above findings and contributions of this work have been further elaborated in the conclusions.

Microdiffraction Patterns of Small Metallic Particles II; Theoretical Analysis

1982 ◽  
Vol 40 ◽  
pp. 668-669
Author(s):  
A. Gómez ◽  
P. Schabes-Retchkiman ◽  
M. José-Yacamán ◽  
T. Ocaña
Keyword(s):  
Experimental Data ◽  
Electron Diffraction ◽  
Theoretical Analysis ◽  
Size Range ◽  
Dynamical Theory ◽  
Metallic Particles ◽  
Splitting Effect

The splitting effect that is observed in microdiffraction pat-terns of small metallic particles in the size range 50-500 Å can be understood using the dynamical theory of electron diffraction for the case of a crystal containing a finite wedge. For the experimental data we refer to part I of this work in these proceedings.

Prospects for convergent beam electron diffraction with a 200kV cold field-emission transmission electron microscope

1991 ◽  
Vol 49 ◽  
pp. 466-467
Author(s):  
J W Steeds ◽  
R Vincent
Keyword(s):  
Field Emission ◽  
High Performance ◽  
Small Diameter ◽  
Convergent Beam Electron Diffraction ◽  
Zone Axis ◽  
Medium Voltage ◽  
Transmission Electron ◽  
Good Crystallinity ◽  
Special Modification ◽  
Convergent Beam

We review the analytical powers which will become more widely available as medium voltage (200-300kV) TEMs with facilities for CBED on a nanometre scale come onto the market. Of course, high performance cold field emission STEMs have now been in operation for about twenty years, but it is only in relatively few laboratories that special modification has permitted the performance of CBED experiments. Most notable amongst these pioneering projects is the work in Arizona by Cowley and Spence and, more recently, that in Cambridge by Rodenburg and McMullan.There are a large number of potential advantages of a high intensity, small diameter, focussed probe. We discuss first the advantages for probes larger than the projected unit cell of the crystal under investigation. In this situation we are able to perform CBED on local regions of good crystallinity. Zone axis patterns often contain information which is very sensitive to thickness changes as small as 5nm. In conventional CBED, with a lOnm source, it is very likely that the information will be degraded by thickness averaging within the illuminated area.

Atomic structure imaging of the Si/SiO2 interface with high-resolution electron microscopy

1986 ◽  
Vol 44 ◽  
pp. 390-391
Author(s):  
J.L. Batstone ◽  
J.M. Gibson ◽  
Alice.E. White ◽  
K.T. Short
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Atomic Structure ◽  
High Resolution Electron Microscopy ◽  
Medium Voltage ◽  
Voltage Electron ◽  
Resolution Electron ◽  
Structural Image ◽  
Electron Microscopes ◽  
Point To Point

High resolution electron microscopy (HREM) is a powerful tool for the determination of interface atomic structure. With the previous generation of HREM's of point-to-point resolution (rpp) >2.5Å, imaging of semiconductors in only <110> directions was possible. Useful imaging of other important zone axes became available with the advent of high voltage, high resolution microscopes with rpp <1.8Å, leading to a study of the NiSi2 interface. More recently, it was shown that images in <100>, <111> and <112> directions are easily obtainable from Si in the new medium voltage electron microscopes. We report here the examination of the important Si/Si02 interface with the use of a JEOL 4000EX HREM with rpp <1.8Å, in a <100> orientation. This represents a true structural image of this interface.

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