Direct torque control of permanent magnet synchronous motors with non-sinusoidal back-EMF

This work presents the direct torque control (DTC) techniques, implemented in four- and six-switch inverter, for brushless dc (BLDC) motors with non-sinusoidal back- EMF using two and three-phase conduction modes. First of all, the classical direct torque control of permanent magnet synchronous motor (PMSM) with sinusoidal back-EMF is discussed in detail. Secondly, the proposed two-phase conduction mode for DTC of BLDC motors is introduced in the constant torque region. In this control scheme, only two phases conduct at any instant of time using a six-switch inverter. By properly selecting the inverter voltage space vectors of the two-phase conduction mode from a simple look-up table the desired quasi-square wave current is obtained. Therefore, it is possible to achieve DTC of a BLDC motor drive with faster torque response while the stator flux linkage amplitude is deliberately kept almost constant by ignoring the flux control in the constant torque region. Third, the avarege current controlled boost power factor correction (PFC) method is applied to the previously discussed proposed DTC of BLDC motor drive in the constant torque region. The test results verify that the proposed PFC for DTC of BLDC motor drive improves the power factor from 0.77 to about 0.9997 irrespective of the load. Fourth, the DTC technique for BLDC motor using four-switch inverter in the constant torque region is studied. For effective torque control in two phase conduction mode, a novel switching pattern incorporating the voltage vector look-up table is designed and implemented for four-switch inverter to produce the desired torque characteristics. As a result, it is possible to achieve two-phase conduction DTC of a BLDC motor drive using four-switch inverter with faster torque response due to the fact that the voltage space vectors are directly controlled.. Finally, the position sensorless direct torque and indirect flux control (DTIFC) of BLDC motor with non-sinusoidal back-EMF has been extensively investigated using three-phase conduction scheme with six-switch inverter. In this work, a novel and simple approach to achieve a low-frequency torque ripple-free direct torque control with maximum efficiency based on dq reference frame similar to permanent magnet synchronous motor (PMSM) drives is presented

Modelling, simulation and analysis of low-cost direct torque control of PMSM using hall-effect sensors

This thesis focuses on the development of a novel Direct Torque Control (DTC) scheme for permanent magnet (PM) synchronous motors (surface and interior types) in the constant torque region with the help of cost-effective hall-effect sensors. This method requires no DC-link sensing, which is a mandatory matter in the conventional DTC drives, therefore it reduces the cost of a conventional DTC of a permanent magnet (PM) synchronous motor and also removes common problems including; resistance change effect, low speed and integration drift. Conventional DTC drives require at least one DC-link voltage sensor (or two on the motor terminals) and two current sensors because of the necessary estimation of position, speed, torque, and stator flux in the stationary reference frame. Unlike the conventional DTC drive, the proposed method uses the rotor reference frame because the rotor position is provided by the three hall-effect sensors and does not require expensive voltage sensors. Moreover, the proposed algorithm takes the acceleration and deceleration of the motor and torque disturbances into account to improve the speed and torque responses. The basic theory of operation for the proposed topology is presented. A mathematical model for the proposed DTC of the PMSM topology is developed. A simulation program written in MATLAB/SIMULINKî is used to verify the basic operation (performance) of the proposed topology. The mathematical model is capable of simulating the steady-state, as well as dynamic response even under heavy load conditions (e.g. transient load torque at ramp up). It is believed that the proposed system offers a reliable and low-cost solution for the emerging market of DTC for PMSM drives. Finally the proposed drive, considering the constant torque region operation, is applied to the agitation part of a laundry washing machine (operating in constant torque region) for speed performance comparison with the current low-cost agitation cycle speed control technique used by washing machine companies around the world

Revisiting the role of renewable and non-renewable energy consumption on Turkey’s ecological footprint: Evidence from Quantile ARDL approach

The current study re-investigates the impact of renewable and non-renewable energy consumption on Turkey’s ecological footprint. This study applies Quantile Autoregressive Lagged (QARDL) approach for the period of 1965Q1-2017Q4. We further apply Granger-causality in Quantiles to check the causal relationship among the variables. The results of QARDL show that error correction parameter is statistically significant with the expected negative sign for all quantiles which confirm an existence of significant reversion to the long-term equilibrium connection between the related variables and ecological footprint in Turkey. In particular, the outcomes suggested that renewable energy decrease ecological footprint in long-run on each quantile. However, the results of economic growth and non-renewable energy impact positively to ecological footprint in long-short run period at all quantiles. Finally, we tested the Environmental Kuznets Curve (EKC) hypothesis and the results of QARDL confirmed the EKC in Turkey. Furthermore, the findings of causal investigation from Granger-causality in quantiles evident the presence of a bi-directional causal relationship between renewable energy consumption, energy consumption and economic growth with ecological footprint in the Turkish economy

PARAMETRICAL METHOD OF LOW-FREQUENCY HARMONICS SUPPRESSION IN RECTIFIER’S OUTPUT VOLTAGE UNDER SUPPLY VOLTAGE UNBALANCES (MATHEMATICAL MODEL, STUDY AND INDUSTRIAL APPLICATION)

This paper deals with using an original and pure electronic method for low-frequency harmonic suppression with wide industrial realization and application, in place of the usually heavy inductive, low-frequency harmonic filters. One of the main applications was made for small land power supply units of onboard complexesin ground-based air navigation when preflight ground check-service is made. The transport management at thousands of small provincial airports in the former country is still unfortunate. The same situation is in Northern and central Central Asia, Northern Caucasian and Trans-Caucasian Mountains, oriented to small civil and agricultural services airports, etc. Everywhere the phaseand line voltage amplitude unbalance can reach between 10-15% at the settlement’s power tiny transformer or generator and there are thousands and thousands of such local «airports» [1, 6]. This paperhas been editing by a native speaker, Ms. Rachel Alcorn — our sincere thanks

The clinical, cytogenetics and molecular characterization of inverted duplication/deletion of chromosome 8p in a boy with mental and motor retardation: Genotype-phenotype correlation in a case report

Background: Rearrangements that occur mainly through the non-allelic homologous recombination (NAHR) during maternal meiosis in short arms of chromosome 8 is relatively associated with various clinical spectrum.Aim: The objective of this study was to report cytogenetics and molecular characterization of a mental and motor retarded boy with short arm of chromosome 8 rearrangements [invdupdel(8p)] in this current case report. Subjects and methods: We report an 11-year-old boy with scoliosis, intellectual disability, mental-motor retardation and characteristic facial features. Agenesis of corpus callosum was detected with brain Magnetic Resonance Imaging (MRI) analysis. Derivative chromosome 8 structure was identified after conventional cytogenetics – karyotype analysis, Multiplex Ligation-Dependent Probe Amplification (MLPA) and Microarray-based Comparative Genomic Hybridization (aCGH) techniques. Genotype-phenotype correlation in the current proband case will be discussed.Results: Case was diagnosed as 46, XY, der (8), del (8) (p23.1) invdup (8) (p11.1-p23.1) by using advanced comparable techniques. Subtelomeric MLPA analysis showed deletion of FBXO25 gene which is located at 8p23.3 locus and FISH with subtelomeric probes for 8p shows also only deleted region. The microarray- CGH profilling showed 7,9 mb deletion for 8p23.1 and 31 mb duplication for 8p11.1 locuses.Conclusion: Results from the current case emphasized that the cases with clinical manifestations of such disorders extremely need to be examined by combined comparable genetics techniques such as; karyotyping, FISH, MLPA and chromosomal microarray for the accurate phenotype – genotype correlation.Keywords: Chromosomal rearrangement, Corpus callosum, Invdupdel(8p)Array-CGH, MLP

Preparation of Silicon-Antimony based Anode Materials for Lithium-Ion Batteries

I n this study, SixSb immiscible composite blend as anode materials have been synthesized using micron-sized silicone and antimony particles in different compositions through chemical reduction-mechanical alloying method CR-MA . The obtained microstructures have been investigated by X-ray diffraction XRD and Scanning Electron Microscopy SEM with Energy Dispersive X-Ray analysis EDX . Spectroscopic characterizations of the composite materials showed that a traditional intermetallic compound could not be achieved. However a novel immiscible composite blend system have been developed. One of the newly prepared composite materials, Si0.65Sb, exhibits an initial capacity of 790 mAh g-1 and a good cyclic stability compared to the pure silicone. The battery performance results of the micron-sized Si0.65Sb blend system have been compared with the commercially used graphite and the nano-sized Si/Sb alloy systems. The cycling stability of the micron-sized Si0.65Sb blend system showed an improvement compared to nano-sized Si/Sb alloy systems. Moreover its specific capacity is slightly higher than the commercial graphite anode material. These results portray the importance of micron sized Si/Sb system in large-scale applications due to its low cost

Seroprevalence of Brucellosis among Children in the Middle Anatolia Region of Turkey

Brucellosis is an important public-health problem in Turkey. Children may constitute 20 to 30% of all brucellosis cases in the world, especially in the endemic regions. Data on the seroprevalence of brucellosis in childhood are very limited. In this study, we aimed to evaluate the seroprevalence of brucellosis among a child population. One thousand one hundred and ten subjects were included in the study. Blood samples were collected and tested with Rose Bengal (RB) and standard tube agglutination test (SAT). RB test results were positive for 6 patients, and SAT was negative for all patients. Our findings suggest that seroprevalence of brucellosis is decreasing in Middle Anatolia due to a new cattle vaccination and eradication programme which was initiated in 2009

WRN Mutation Update: Mutation Spectrum, Patient Registries, and Translational Prospects: HUMAN MUTATION

Werner syndrome (WS) is a rare autosomal recessive disorder characterized by a constellation of adult onset phenotypes consistent with an acceleration of intrinsic biological aging. It is caused by pathogenic variants in the WRN gene, which encodes a multifunctional nuclear protein with exonuclease and helicase activities. WRN protein is thought to be involved in optimization of various aspects of DNA metabolism, including DNA repair, recombination, replication, and transcription. In this update, we summarize a total of 83 different WRN mutations, including eight previously unpublished mutations identified by the International Registry of Werner Syndrome (Seattle, WA) and the Japanese Werner Consortium (Chiba, Japan), as well as 75 mutations already reported in the literature. The Seattle International Registry recruits patients from all over the world to investigate genetic causes of a wide variety of progeroid syndromes in order to contribute to the knowledge of basic mechanisms of human aging. Given the unusually high prevalence of WS patients and heterozygous carriers in Japan, the major goal of the Japanese Consortium is to develop effective therapies and to establish management guidelines for WS patients in Japan and elsewhere. This review will also discuss potential translational approaches to this disorder, including those currently under investigation

A MSFD complementary approach for the assessment of pressures, knowledge and data gaps in Southern European Seas : the PERSEUS experience

PERSEUS project aims to identify the most relevant pressures exerted on the ecosystems of the Southern European Seas (SES), highlighting knowledge and data gaps that endanger the achievement of SES Good Environmental Status (GES) as mandated by the Marine Strategy Framework Directive (MSFD). A complementary approach has been adopted, by a meta-analysis of existing literature on pressure/impact/knowledge gaps summarized in tables related to the MSFD descriptors, discriminating open waters from coastal areas. A comparative assessment of the Initial Assessments (IAs) for five SES countries has been also independently performed. The comparison between meta-analysis results and IAs shows similarities for coastal areas only. Major knowledge gaps have been detected for the biodiversity, marine food web, marine litter and underwater noise descriptors. The meta-analysis also allowed the identification of additional research themes targeting research topics that are requested to the achievement of GES. 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license.peer-reviewe