scholarly journals Common-Ground Photovoltaic Inverters for Leakage Current Mitigation: Comparative Review

2021 ◽  
Vol 11 (23) ◽  
pp. 11266
Author(s):  
Mahmoud A. Gaafar ◽  
Mohamed Orabi ◽  
Ahmed Ibrahim ◽  
Ralph Kennel ◽  
Mohamed Abdelrahem
Keyword(s):  
Leakage Current ◽  
Performance Indicators ◽  
High Frequency ◽  
Common Ground ◽  
Parasitic Capacitance ◽  
Pv Systems ◽  
Advantages And Disadvantages ◽  
Comparative Review ◽  
Grid Side ◽  
The Cost

In photovoltaic systems, parasitic capacitance is often formed between PV panels and the ground. Because of the switching nature of PV converters, a high-frequency voltage is usually generated over these parasitic capacitances; this, in turn, can result in a common-mode current known as leakage current. This current can badly reach a high value if a resonance circuit is excited through the PV’s parasitic capacitance and the converter’s inductive components. Transformers are usually used for leakage current mitigation. However, this decreases the efficiency and increases the cost, size, and weight of the PV systems. Number of strategies have been introduced to mitigate the leakage current in transformer-less converters. Among these strategies, using common-ground converters is considered the most effective solution as it offers a solid connection between the negative terminal of PV modules and the neutral of the grid side; thus, complete mitigation of the leakage current is achieved. Number of common-ground inverters have been recently presented. These inverters are different in their size, cost, boosting capability, the possibility of producing DC currents, and their capability to offer multilevel shaping of output voltage. This work introduces a comprehensive review and classification for various common-ground PV inverters. Therefore, a clear picture of the advantages and disadvantages of these inverters is clarified. This provides a useful indication for a trade-off between gaining some of the advantages and losing others in PV systems. In addition, the potentials for optimization based on different performance indicators are identified.

scholarly journals Analysis of transformer less inverter for PV applications

2018 ◽  
Vol 7 (2-1) ◽  
pp. 427
Author(s):  
Selvamathi R ◽  
Indragandhi V ◽  
Ashok kumar L
Keyword(s):  
Leakage Current ◽  
Research Paper ◽  
Parasitic Capacitance ◽  
Pv System ◽  
Safety Issues ◽  
Pv Systems ◽  
Pv Inverter ◽  
The Cost

To enhance the effectiveness and decrease the cost of a Photovoltaic (PV) system, the utilization of transformer less PV inverters is an option of expanding interest. In any case, this topology should be considered in detail, as it shows a few issues like effectiveness degradation and safety issues identified with the galvanic association between the system and the PV generator.In this research paper, a review of standalone and grid-connected PV inverter structures has been done. From one viewpoint, a few options in light of established structures have been introduced. At last parasitic capacitance in PV arrays and leakage current produced from PV systems are examined.

scholarly journals Transformerless Multilevel Voltage-Source Inverter Topology Comparative Study for PV Systems

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3261 ◽  
Author(s):  
Adyr A. Estévez-Bén ◽  
Alfredo Alvarez-Diazcomas ◽  
Juvenal Rodríguez-Reséndiz
Keyword(s):  
Leakage Current ◽  
Clean Energy ◽  
Industrial Applications ◽  
Renewable Energies ◽  
International Standards ◽  
Voltage Source ◽  
Switching Frequency ◽  
Multilevel Inverters ◽  
Pv Systems ◽  
Advantages And Disadvantages

At present, renewable energies represent 25% of the global power generation capacity. The increase in clean energy facilities is mainly due to the high levels of pollution generated by the burning of fossil fuels to satisfy the growing electricity demand. The global capacity of generating electricity from solar energy has experienced a significant increase, reaching 505 GW in 2018. Today, multilevel inverters are used in PV systems to convert direct current into alternating current. However, the use of multilevel inverters in renewable energies applications presents different challenges; for example, grid-connected systems use a transformer to avoid the presence of leakage currents. The grid-connected systems must meet at least two international standards analyzed in this work: VDE 0126-1-1 and VDE-AR-N 4105, which establish a maximum leakage current of 300 mA and harmonic distortion maximum of 5%. Previously, DC/AC converters have been studied in different industrial applications. The state-of-the-art presented in the work is due to the growing need for a greater use of clean energy and the use of inverters as an interface between these technologies and the grid. Also, the paper presents a comparative analysis of the main multilevel inverter voltage-source topologies used in transformerless PV systems. In each scheme, the advantages and disadvantages are presented, as well as the main challenges. In addition, current trends in grid-connected systems using these schemes are discussed. Finally, a comparative table based on input voltage, switching frequency, output levels, control strategy used, efficiency, and leakage current is shown.

scholarly journals Reduction EMI of BLDC Motor Drive Based on Software Analysis

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Navid Mousavi ◽  
Tohid Rahimi ◽  
Homayoun Meshgin Kelk
Keyword(s):  
Leakage Current ◽  
High Frequency ◽  
Common Ground ◽  
Motor Drive ◽  
Electronic Systems ◽  
Bldc Motor ◽  
Leakage Currents ◽  
Software Analysis ◽  
Frequency Components ◽  
Motor Drive System

In the BLDC motor-drive system, the leakage current from a motor to a ground network and existence of high-frequency components of the DC link current are the most important factors that cause conducting interference. The leakage currents of the motors, flow through common ground, will interfere with other equipment because of the high density of electrical and electronic systems in the spacecraft and aircrafts. Moreover, generally there are common DC buses in the mentioned systems, which aggravate the problem. Function of the electric motor causes appearance of the high-frequency components in the DC link current, which can interfere with other subsystems. In this paper, the analysis of electromagnetic noise and presentation of the proposed method based on the frequency spectrum of the DC link current and the leakage current from the motor to the ground network are done. The proposed method presents a new process based on the filtering method to overcome EMI. To cover the requirement analysis, the Maxwell software is used.

scholarly journals High Frequency InGaAs MOSFET with Nitride Sidewall Design for Low Power Application

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Jiongjiong Mo ◽  
Hua Chen ◽  
Zhiyu Wang ◽  
Faxin Yu
Keyword(s):  
Low Power ◽  
Leakage Current ◽  
High Frequency ◽  
Current Problem ◽  
Device Simulation ◽  
Parasitic Capacitance ◽  
Thermal Budget ◽  
Drain Side ◽  
Power Application ◽  
Ingaas Mosfet

InxGa1-xAsdevices have been widely researched for low power high frequency applications due to the outstanding electron mobility and small bandgap of the materials. Regrown source/drain technology is highly appreciated in InGaAs MOSFET, since it is able to reduce the thermal budget induced by ion implantation, as well as reduce the source/drain resistance. However, regrown source/drain technology has problems such as high parasitic capacitance and high electric field at gate edge towards the drain side, which will lead to large drain leakage current and compromise the frequency performance. To alleviate the drain leakage current problem for low power applications and to improve the high frequency performance, a novel Si3N4sidewall structure was introduced to the InGaAs MOSFET. Device simulation was carried out with different newly proposed sidewall designs. The results showed that both the drain leakage current and the source/drain parasitic capacitance were reduced by applying Si3N4sidewall together with InP extended layer in InGaAs MOSFET. The simulation results also suggested that the newly created “recessed” sidewall was able to bring about the most frequency favorable characteristic with no current sacrifice.

Main approaches to estimating the cost of shareholder equity of oil and gas producers

2020 ◽  
Vol 26 (3) ◽  
pp. 685-697
Author(s):  
O.V. Shimko
Keyword(s):  
Oil And Gas ◽  
Oil Prices ◽  
Minimum Cost ◽  
Free Cash Flow ◽  
Annual Reports ◽  
Comparative Approach ◽  
Economic Activities ◽  
Advantages And Disadvantages ◽  
Oil And Gas Producers ◽  
The Cost

Subject. The study analyzes generally accepted approaches to assessing the value of companies on the basis of financial statement data of ExxonMobil, Chevron, ConocoPhillips, Occidental Petroleum, Devon Energy, Anadarko Petroleum, EOG Resources, Apache, Marathon Oil, Imperial Oil, Suncor Energy, Husky Energy, Canadian Natural Resources, Royal Dutch Shell, Gazprom, Rosneft, LUKOIL, and others, for 1999—2018. Objectives. The aim is to determine the specifics of using the methods of cost, DFC, and comparative approaches to assessing the value of share capital of oil and gas companies. Methods. The study employs methods of statistical analysis and generalization of materials of scientific articles and official annual reports on the results of financial and economic activities of the largest public oil and gas corporations. Results. Based on the results of a comprehensive analysis, I identified advantages and disadvantages of standard approaches to assessing the value of oil and gas producers. Conclusions. The paper describes pros and cons of the said approaches. For instance, the cost approach is acceptable for assessing the minimum cost of small companies in the industry. The DFC-based approach complicates the reliability of medium-term forecasts for oil prices due to fluctuations in oil prices inherent in the industry, on which the net profit and free cash flow of companies depend to a large extent. The comparative approach enables to quickly determine the range of possible value of the corporation based on transactions data and current market situation.

Classification of the factors forming the cost of the web-site

2017 ◽  
Vol 31 (2) ◽  
pp. 82-89
Author(s):  
E. S. Epifanov
Keyword(s):  
Web Site ◽  
Internet Site ◽  
Advantages And Disadvantages ◽  
Major Factors ◽  
The Cost ◽  
The Web

This article presents a classification of major factors that shape the cost of Internet site. Also discusses the limitations in determining the objectives of the web site; advantages and disadvantages of different factors.

scholarly journals Light-Load Efficiency Improvement for Ultrahigh Step-Down Converter Based on Skip Mode

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 355
Author(s):  
Yeu-Torng Yau ◽  
Chao-Wei Wang ◽  
Kuo-Ing Hwu
Keyword(s):  
Integrated Circuit ◽  
Common Ground ◽  
Switching Frequency ◽  
Efficiency Improvement ◽  
Pulse Width Modulated ◽  
Light Load ◽  
Mode 2 ◽  
Skip Mode ◽  
Step Down ◽  
The Cost

In this paper, two light-load efficiency improvement methods are presented and applied to the ultrahigh step-down converter. The two methods are both based on skip mode control. Skip Mode 1 only needs one half-bridge driver integrated circuit (IC) to drive three switches, so it has the advantages of easy signal control and lower cost, whereas Skip Mode 2 requires one half-bridge driver integrated circuit IC, one common ground driver IC, and three independent timing pulse-width-modulated (PWM) signals to control three switches, so the cost is higher and the control signals are more complicated, but Skip Mode 2 can obtain slightly higher light-load efficiency than Skip Mode 1. Although the switching frequency used in these methods are reduced, the transferred energy is unchanged, but the output voltage ripple is influenced to some extent.

scholarly journals Analysis and Design of a Multi-Port DC-DC Converter for Interfacing PV Systems

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1943
Author(s):  
Bader N. Alajmi ◽  
Mostafa I. Marei ◽  
Ibrahim Abdelsalam ◽  
Mohamed F. AlHajri
Keyword(s):  
High Frequency ◽  
Computer Aided Design ◽  
Electromagnetic Transients ◽  
Pv System ◽  
Analysis And Design ◽  
Pv Systems ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Power Point ◽  
Aided Design

A high-frequency multi-port (HFMP) direct current (DC) to DC converter is presented. The proposed HFMP is utilized to interface a photovoltaic (PV) system. The presented HFMP is compact and can perform maximum power point tracking. It consists of a high-frequency transformer with many identical input windings and one output winding. Each input winding is connected to a PV module through an H-bridge inverter, and the maximum PV power is tracked using the perturb and observe (P&O) technique. The output winding is connected to a DC bus through a rectifier. The detailed analysis and operation of the proposed HFMP DC-DC converter are presented. Extensive numerical simulations are conducted, using power system computer aided design (PSCAD)/electromagnetic transients including DC (EMTDC) software, to evaluate the operation and dynamic behavior of the proposed PV interfacing scheme. In addition, an experimental setup is built to verify the performance of the HFMP DC-DC converter.

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