A Comparative Analysis of Field Oriented Control and Direct Torque Control of Induction Motor Drive

Electric Motor Drive System is employed in the various industrial applications such as pumping, air blowing, cooling and compression refrigeration. The motor drive speed control can be achieved by variety of techniques, but an emerging one is Variable Frequency Drive System (VFDS). The motor driven equipment on a typical industrial site accounts for approximately two thirds of the electricity consumption. Now-a-days induction motor is the main work-horse of the industries. So controlling of performance of induction motor is most precisely required in many high performance applications. Scalar control method gives good steady state response but poor dynamic response. While vector control method gives good steady state as well as dynamic response. But it is complicated in structure so to overcome this difficulty, direct torque control introduced. This paper discusses the comparative analysis of Field Oriented Control (FOC) and Direct Torque Control (DTC) methods of Polyphase Induction Motor (PIM) according to their working principle, structure complexity, performance, merits and demerits

Design and Simulation of Control strategies for Voltage Source PWM Rectifier

Power Electronics is defined as branch of science, engineering and technology which deals with Power Electronics Modulators (PEM) in which efficient conversion, conditioning, processing, controlling and modulating the flow of large electric power using Solid State Power Semiconductor Device (SSPSD) in order to supply high quality power to the load which causes minimum pollution of physical characteristics of electric power with regulating stability and response characteristics of the closed loop system and its application. Diode rectified circuit and thyristor rectifiers circuit are widely used in the conventional rectifier circuit, but the problems arising during operating should not be ignored, such as, harmonic problems and low power factor. These problems may do harm to the grid, which in turn cause a series consequences, therefore, the application of such rectifier will be limited. With the continuous development of PWM technology people pay attention to the PWM rectifier gradually. The paper first analyzes the mathematical model of three-phase voltage-source PWM rectifier and then introduces double closed-loop control of voltage and current system, in which the active and reactive power can be controlled independently. PWM rectifier control system is built based on the DSP2812 after modeling and simulating in MATLAB / SIMULINK environment. The result shows that the system has the characteristic of good anti-interference performance and fast dynamic response

Analysis and Assessment of Motor Drive Speed Control through Variable Frequency Drive

Electric Motor Drive System is employed in the various industrial applications such as pumping, air blowing, cooling and compression refrigeration. The motor drive speed control can be achieved by variety of techniques, but an emerging one is Variable Frequency Drive System. The motor driven equipment on a typical industrial site accounts for approximately two thirds of the electricity consumption. Therefore, any type of measure taken to improve the efficiency of a motor system consequently can offer major energy savings. There are multiple benefits of variable frequency drive system utilizing along with speed control. For the technical and economic reliability of such integrated approach of motor with variable frequency drive, analysis and assessment is the key tool. This paper first outlines the benefits of Variable Frequency Drives (VFD) compared to classical drivers or control methods (i.e. steam/gas turbines, hydraulic coupling and Direct-On-Line operation with, for example, valve/damper control). The paper then focuses on analysis and assessment of typical variable frequency drive applications in the sugar industry and also describes a real case study, namely a VFD soft-starter application at Narmada Sugar Factory, Bharuch

Design of Resistance Spot Welding System using Integral Switching Cycle Control Technique

The process of combining metal of similar composition by heating at suitable temperature with or without pressure and application of filler material is known as Welding. Resistance Spot Welding (RSW) is defined as a process which requires simultaneous application of high electrical current and appropriate pressure over short periods in order to keep the molten material inside the weld zone. Values of these parameters are varied in function of the characteristics of the materials to be welded. The application of the electrical current carrying two copper electrodes brought in contact with the welded parts while the required pressure is applied by means of pneumatic or hydraulic systems. This paper presents a novel design of resistance welding system using Integral Switching Cycle Control Technique used for performing a welding process. The paper is discussed about two aspects. First, a brief introduction about welding, methods of welding control and electronic control used in resistance welding. Secondly, the critical factors in design of a welding process are dealt along with the principle of the welding process. Following this, the introduction to the design of control scheme employed with the basic block diagram of welding system and its functioning is presented

A Comparative Evaluation of Wave Shaping Methods for AC-DC Power Electronics Converter

Power Electronics is defined as branch of science, engineering and technology which deals with Power Electronics Modulators (PEM) in which efficient conversion, conditioning, processing, controlling and modulating the flow of large electric power using Solid State Power Semiconductor Device (SSPSD) in order to supply high quality power to the load which causes minimum pollution of physical characteristics of electric power with regulating stability and response characteristics of the closed loop system and its application. The comparative study of Passive and Active Wave Shaping (AWS) filter based on Current-Source Fed Switch Mode Rectifier (CSFSMR) converter supplied from single-phase AC supply is carried out in this paper in which two circuit are designed and implemented in MATLAB Simulink. Usually a boost converter is working as Active Harmonic Filter to reduce the harmonics at the main supply by controlling the duty cycle of the filter while Passive wave shaping filter reduce the harmonics at the supply in a simple way. Depending on rating, schematic and control complexities, control performance and cost, there are many possible power factor correction approaches. The suited and cost effective one can be chosen according to the desired performance for specific application

Partnership and Capacity Building of Local Governance

Partnership is about sharing of power, responsibility and achievements. According to the World Bank Public Private Partnership (PPP) promoting group, ―partnership refer to informal and shortterm engagements of non-governmental organizations, the private sector and/or government agencies that join forces for a shared objective; to more formal, but still short-term private sector engagements for the provision of specific services, for example, annual outsourcing arrangements for janitorial services for a school or operations of the school cafeteria; to more complex contractual arrangements, such as build, operate, transfer regimes, where the private sector takes on considerable risk and remains engaged long term; or to full privatizations‖ (World Bank Group 2014, 29).© Springer Nature Switzerland AG 2020. This is a post-peer-review, pre-copyedit version of an article published in Partnerships for the Goals. Encyclopedia of the UN Sustainable Development Goals. The final authenticated version is available online at: http://dx.doi.org/10.1007/978-3-319-71067-9_21-1.fi=vertaisarvioitu|en=peerReviewed

Genetic, environmental and stochastic factors in monozygotic twin discordance with a focus on epigenetic differences

PMCID: PMC3566971This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Proteomic Analysis of the Cyst Stage of Entamoeba histolytica

We used tandem mass spectrometry to identify E. histolytica cyst proteins in 5 cyst positive stool samples. We report the identification of 417 non-redundant E. histolytica proteins including 195 proteins that were not identified in existing trophozoite derived proteome or EST datasets, consistent with cyst specificity. Because the cysts were derived directly from patient samples with incomplete purification, a limited number of proteins were identified (N = 417) that probably represent only a partial proteome. Nevertheless, the study succeeded in identifying proteins that are likely to be abundant in the cyst stage of the parasite. Several of these proteins may play roles in E. histolytica stage conversion or cyst function. Proteins identified in this study may be useful markers for diagnostic detection of E. histolytica cysts. Overall, the data generated in this study promises to aid the understanding of the cyst stage of the parasite which is vital for disease transmission and pathogenesis in E. histolytica

Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy

Background A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets. Methods Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis. Results A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001). Conclusion We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty

Increased therapeutic potential of an experimental anti-mitotic inhibitor SB715992 by genistein in PC-3 human prostate cancer cell line

BACKGROUND: Kinesin spindle proteins (KSP) are motor proteins that play an essential role in mitotic spindle formation. HsEg5, a KSP, is responsible for the formation of the bipolar spindle, which is critical for proper cell division during mitosis. The function of HsEg5 provides a novel target for the manipulation of the cell cycle and the induction of apoptosis. SB715992, an experimental KSP inhibitor, has been shown to perturb bipolar spindle formation, thus making it an excellent candidate for anti-cancer agent. Our major objective was a) to investigate the cell growth inhibitory effects of SB715992 on PC-3 human prostate cancer cell line, b) to investigate whether the growth inhibitory effects of SB715992 could be enhanced when combined with genistein, a naturally occurring isoflavone and, c) to determine gene expression profile to establish molecular mechanism of action of SB715992. METHODS: PC-3 cells were treated with varying concentration of SB715992, 30 μM of genistein, and SB715992 plus 30 μM of genistein. After treatments, PC-3 cells were assayed for cell proliferation, induction of apoptosis, and alteration in gene and protein expression using cell inhibition assay, apoptosis assay, microarray analysis, real-time RT-PCR, and Western Blot analysis. RESULTS: SB715992 inhibited cell proliferation and induced apoptosis in PC-3 cells. SB715992 was found to regulate the expression of genes related to the control of cell proliferation, cell cycle, cell signaling pathways, and apoptosis. In addition, our results showed that combination treatment with SB715992 and genistein caused significantly greater cell growth inhibition and induction of apoptosis compared to the effects of either agent alone. CONCLUSION: Our results clearly show that SB715992 is a potent anti-tumor agent whose therapeutic effects could be enhanced by genistein. Hence, we believe that SB715992 could be a novel agent for the treatment of prostate cancer with greater success when combined with a non-toxic natural agent like genistein