Implementation of Matrix Converter in Wind Energy Conversion System with Modified Control Techniques

Abstract

In this article, different matrix converter (MC) control strategies are comprehensively explained. Further, an ultra-modified space vector modulation (UMSVM) of the MC is proposed. The total harmonic distortion for both output voltage and current is reduced, when the proposed UMSVM technique is applied. Moreover, a modified indirect space vector modulation with feed forward controller (MISVMFC) of the MC is also proposed in order to obtain a fixed output voltage and frequency for different wind speeds. The advantages of the MC are introduced in this article. These advantages include the wide range of the output frequency of MC, which may be greater than the input frequency and the control of both the output voltage magnitude and input displacement factor (IDF). Extensive theoretical and simulation results about conventional and proposed control techniques for the MC are presented. Experimental test bench is constructed and several experimental results are obtained. The experimental results validate the simulation ones.     

Innovative surfactant of Gemini-type for dissolution mitigation of steel in pickling HCl medium

A new surfactant of Gemini-type,N,N'-((phthylbis(oxy))bis(ethane-2,1-diyl))bis(N,N-dimethyldodecan-1-aminium bromide) is prepped confirmed.The dissolution suppression impact of the new compound on steel is performed in 1 mol·L~(-1) HCl environment by means of chemical and electrochemical methods.The prepared surfactant is an agreeable dissolution inhibitor for steel.The mitigation efficacy rises with the quantity of the compound.The surfactant belongs to inhibitors of mixed-type.The adsorption of the synthesized compound followed the Langmuir's model.The negative magnitudes of both ΔG_(ads)~θ and ΔH~(adsθ)indicate that the adsorption process proceeds from its own accord and exothermic.The mechanism of adsorption is elucidated by scanning microscopy.It is established that the transfer resistance(R_(ct)) value rose,where the value of the phase element(CPE) reduced with the amount of synthesized inhibitor.According to the experimental data arrived by surface tension measurements,the prepared compound is a powerful active agent at the air/water boundary.     

320 Gb/s all-optical XOR gate using semiconductor optical amplifier-Mach–Zehnder interferometer and delayed interferometer

Photonic Network Communications - All-optical exclusive OR (XOR) gate with semiconductor optical amplifier (SOA)-Mach–Zehnder interferometer (MZI) and delayed interferometer (DI) is...     

An Accurate Technique for Discrimination between Transient and Permanent Faults in Transmission Networks

This paper presents an assessment study for adaptive single-pole automatic reclosure (ASPAR) schemes to select correctly the best scheme at responsible indices. Suggested solutions for the drawbacks that were noticed with the previous methods are investigated. In addition, this paper presents a proposed technique for ASPAR on transmission lines using wavelet packet transform (WPT). The ASPAR aims to discriminate between the faults' natures and to detect the instant of arc extinguished. The proposed technique uses an adaptive threshold level, and therefore, no adjustment is needed for various transmission systems. The proposed technique is examined at different fault scenarios that involve different fault locations, inception angles, and representation to secondary arc characteristics with various arc models. In addition, the behavior of ASPAR is well studied under power swing situation. The effects of shunt reactor compensators on the proposed technique are checked. The proposed scheme is tested for different network configurations, single and double circuits, to realize the robustness and the capability of the proposed scheme. The ATP/EMTP package is developed to emulate different fault signals to validate the proposed scheme. The proposed adaptive threshold scheme discriminates correctly between permanent and transient faults, thereby enhancing power system stability for compensated and uncompensated networks.     

Modern Friedel-Crafts Chemistry. Part 38. Facile Synthesis of Acenaphthenes via Direct and Rearranged Intramolecular Friedel-Crafts Cyclialkylations of Intermediate Carbinols

A novel one-pot synthesis of six di-, tri-, and tetra-substituted acenaphthenes 18a-f via direct and/or rearranged Friedel-Crafts cyclialkylations of seven novel carbinols 1a-g is described. The methodology involves treatment of alkanols 1a-g in the presence of both Brønsted (PPA, H₂SO₄) and Lewis (AlCl₃/CH₃NO₂) acid catalysts. The method offers several advantages such as high yields, high selectivities, and easily accessible starting materials. A plausible mechanism for this type of Friedel-Crafts cyclialkylation is proposed.     

The oxygen/sulphur dioxide electrode in molten carbonates

A study has been made of the O₂/SO₂ electrode in molten equimolar Li₂CO₃Na₂CO₃ at 600°C. The overall electrode reaction, reaction order with respect to P_SO2 and exchange currents have been determined from open-circuit potential, potentiostatic and voltammetric measurements.     

Adsorption of sulphur dioxide on coal

A study was made of the feasibility of using coal as an adsorbent material for the removal of sulphur dioxide from stack gases emitted to the atmosphere by different industries. From preliminary results, it would appear that coal is to be favoured by a raw materials/cost-effectiveness ratio of 2:1. The work shows semi-quantitatively that the adsorptive capacity of sulphur dioxide on coal varies slightly from one coal to another and that when coal is used and re-used through numerous (?40) cycles, its effectiveness as an adsorbent for sulphur dioxide is not greatly reduced. Moreover, this research supports the view that the heating value, ash, sulphur content, etc. of most types of coal changes only slightly after repeated usage as an adsorbent for sulphur dioxide. If, as these findings indicate, coal can initially be used as a sulphur dioxide adsorbent prior to its use as a fuel, economic potential for commercial applications should be enhanced. Empirical equations, developed to correlate the adsorption-desorption characteristics of different coals, can be used as a basis for prediction and comparison by future investigators to further explore this research.     

Superantigens and experimental SLE induced by idiotypic dysregulation

Electroacupuncture (EA) has been reported to induce changes in skin temperature; however, it is not clear whether high- and low-frequency EA produce similar effects. Therefore, the purpose of this study was to investigate the effects of EA on the skin temperature of the hand and finger in normal subjects. Twenty-one subjects received high-frequency EA (100 Hz) and low-frequency EA (4 Hz) at the Large Intestine 4 and Small Intestine 3 acupuncture points, as well as a no-treatment control condition. The results showed that the skin temperature following high- and low-frequency EA produced significant cooling effects at both sites as compared with the no-treatment control condition during the stimulation period (p < 0.05). These data show that EA produces significant changes in skin temperature that may be of benefit in pathologic conditions that are accompanied by an increase in local circulation.     

Role of antigen-presenting cells in activation of human T cells by the streptococcal M protein superantigen: requirement for secreted and membrane-associated costimulatory factors

The requirements for T-cell activation by the streptococcal superantigen (SAg), pepsin-extracted M protein from type 5 streptococci (pep M5), were studied by monitoring Ca2+ influx and cell proliferation. Cells from a pep M5-specific T-cell line showed no change in intracellular Ca2+ levels in response to pep M5 when added alone or with freshly isolated autologous antigen-presenting cells (APC). However, after being incubated with pep M5 overnight, the APC secreted soluble factors that together with pep M5 induced a marked increase in intracellular Ca2+ levels in pep M5-specific T cells or freshly isolated, purified T cells. Removal of the SAg from the overnight APC-derived supernatants resulted in loss of the Ca(2+)-mobilizing activity, which was restored within seconds of addition of SAg, suggesting that both the SAg and the soluble factors synergize to induce the Ca2+ influx. Induction of cell proliferation required additional signals inasmuch as the activated APC-derived supernatant failed to synergize with pep M5 to induce the proliferation of purified T cells and required the presence of phorbol myristate acetate for this activity. Metabolically inactive, fixed APC were impaired in their ability to present pep M5 to T cells. Presentation of pep M5 by fixed APC was, however, restored when the APC-derived soluble costimulatory factors were added to the culture. Our data suggest that pep M5-induced activation of T cells is dependent on APC-derived soluble factors and an APC membrane-associated costimulatory molecule(s). These interactions may be important in regulating the in vivo responses to M proteins, could contribute to the severity or progression of infections with Streptococcus pyogenes, and may influence the susceptibility of individuals to its associated nonsuppurative autoimmune sequelae.     

NAND gate with quantum dot-semiconductor optical amplifiers-based Mach-Zehnder interferometer

The NAND operation at 250 Gbit/s based on quantum dot-semiconductor optical amplifiers (QD-SOAs) is modeled. By solving the rate equations of SOAs in the form of a Mach-Zehnder interferometer (MZI), the performance of NAND gate is numerically investigated. The model takes the effects of amplified spontaneous emission (ASE) and the input pulse energy on the system’s quality factor into account. Results show that NAND gate in QD-SOA-MZI based structure is feasible at 250 Gbit/s with a proper quality factor. The decrease in quality factor is predicted for high spontaneous emission factor (N _SP). For an ideal amplifier (N _SP = 2), the Q-factor is 17.8 for 30 dB gain.