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This study proposes a flexible, compact, efficient, and cost effective electric vehicle-to-electric vehicle charge sharing solution that will lead to faster and wider customer adoption of electric vehicles (EVs) as an alternative to current grid-to-vehicle charging methodologies. The energy will be transferred between EVs using a bidirectional dc–dc converter in a conductive way, which can take place at parking lots of workplaces, campuses, or residential premises and highways. The proposed design provides compact infrastructure, wide input and output voltage ranges with bidirectional buck–boost operation, and fast power transfer compared to Level 2 charging stations. A complete design comparison between Si and SiC based converters has been carried out based on the available power modules and magnetic cores. The comparison demonstrates the effect of switching frequency and switch selection on the size of passive components, the converter efficiency, and the power density of the converter. The developed study evaluated three different bidirectional dc–dc converter topologies and validated the developed prototype with experimental results.

Hybrid 3-phase stepper motors remain the preferred solution for many applications in robotics and aerospace industries as they can provide accurate position and speed control in open loop systems. On the other hand, they are rarely used in oil and gas industry. In this paper, potential use of this motor technology to oil and gas industry specifically downhole applications is investigated. For this purpose, design and analyses of a 3-phase hybrid stepper motor are carried out with the detailed investigation on the impact of airgap on the motor performance. The difficulty of the design comes from extremely large L/D ratio of the stepper motor due to the application requirements. Fundamental design-based equations are used for the initial design of the motor and detailed 3D finite element analysis (FEA) models are carried out to check the motor performance. Finally, modelling and design of two 3-phase hybrid stepper motors with different airgaps are presented to illustrate the effect of the airgap length on motor performance.

This paper introduces a new control approach to improve the output torque quality of a surface-mounted permanent-magnet synchronous motor with asymmetric windings. The impact of the asymmetry is reflected in the newly developed mathematical model of the motor based on dq0 voltages, flux linkages, and torque. Using this model, a control strategy based on vector control technique is proposed. This algorithm aims to eliminate the zero-sequence current, thereby improving the motor performance. The capability of the proposed algorithm has been demonstrated via simulation and experimental results.

Different disc-type axial flux permanent magnet (AFPM) generators are designed and compared in this article for a Caterpillar D7E track-type tractor (TTT) electric drive model. The design of several feasible generators with multiple stators and rotors are completed for the given electrical and mechanical specifications and compared with a conventional permanent magnet (PM) generator in terms of power density, torque density, loss distribution, efficiency, heat dissipation, volume, inertia, and weight. Electromagnetic, mechanical, and thermal analyses are also accomplished to finalize the designs. The results reveal the benefits of axial gap PM generators over radial gap generators for a hybrid electric traction application.

This paper analyzes critical control issues associated with the deep field weakening operation of interior permanent magnet (IPM) synchronous machines. The singlecurrent-regulator control algorithm is reviewed, which controls the d-axis current actively and gives a fixed q-axis voltage command. To achieve better operational efficiency and performance, improvements are made to choose an optimal q -axis voltage for variable-speed and variable-load conditions. The control algorithm is implemented on a 50-kW IPM machine. Test results, including 7:1 constant power speed ratio operation, are presented to verify the theoretical analysis.

Interior permanent magnet (IPM) synchronous machines can experience large harmonic eddy-current losses in the stator teeth under flux-weakening operation, significantly depressing the efficiency of these machines at high operating speeds. This paper presents a new analytical/finite-element hybrid design approach to reduce the harmonic eddy-current losses in IPM machine stator teeth during flux-weakening operation. The proposed technique achieves this objective by three steps: 1) developing an analytical index for the harmonic eddy-current losses in IPM machine stator teeth; 2) designing the spatial distribution of the rotor MMF to minimize the analytical index; and 3) synthesizing the rotor geometry to implement the desired rotor MMF function while maintaining the basic machine characteristics unchanged. It will be shown that two-layer rotors, if properly optimized, are significantly more effective than one-layer rotors for the purpose of reducing the harmonic eddy-current losses in IPM machine stator teeth during flux-weakening operation at high speeds.

This paper develops analytical principles for torque ripple reduction in interior permanent magnet (IPM) synchronous machines. The significance of slot harmonics and the benefits of stators with odd number of slots per pole pair are highlighted. Based on these valuable analytical insights, this paper proposes coordination of the selection of stators with odd number of slots per pole pair and IPM rotors with multiple layers of flux barriers in order to reduce torque ripple. The effectiveness of using stators with odd number of slots per pole pair in reducing torque ripple is validated by applying a finite-element-based Monte Carlo optimization method to four IPM machine topologies, which are combinations of two stator topologies (even or odd number of slots per pole pair) and two IPM rotor topologies (one- or two-layer). It is demonstrated that the torque ripple can be reduced to less than 5% by selecting a stator with an odd number of slots per pole pair and the IPM rotor with optimized barrier configurations, without using stator/rotor skewing or rotor pole shaping.

A new closed loop current model flux observer is designed to estimate the rotor flux, position and velocity of an induction machine. The current observer includes carefully designed sliding mode functions which are derivative of the fluxes along the /spl alpha/ and /spl beta/ axes. Therefore, when the estimated current converges to the measured one, the flux estimation is a mere integration of the sliding mode function. The rotor speed can then be derived from the sliding mode functions and the estimated flux. In the current and flux observers all of the terms that contain the rotor time constant and the rotor speed have been replaced by the sliding mode functions, thus making the proposed current and flux estimations completely insensitive to the rotor time constant variation and any error in the estimated speed. Simulations and experiments are performed under a variety of conditions to validate the effectiveness of the proposed algorithm.

In this letter, a new sliding-mode-sensorless control algorithm is proposed for the field-oriented induction machine drive. In the proposed algorithm, the terms containing flux, speed, and rotor time constant, which are common in both current and flux equations, in the current model of the induction machine are estimated by a sliding function. The flux and speed estimation accuracy is guaranteed when the error between the actual current and observed current converges to zero. Hence, the fourth-order system is reduced to two second-order systems, and the speed estimation becomes very simple and robust to the parameter uncertainties. The new approach is verified by simulation and experimental results.

Crimean-Congo hemorrhagic fever is a potentially fatal viral disease in humans caused by CCHF virus. We aimed to demonstrate change in serum levels of matrix metallopeinase/tissue matrix metalloproteinase inhibitor (MMP/TIMP) associated with CCHF.Blood specimens were collected in acute and convalescence periods from the patients presented to Cumhuriyet University Hospital, Department of Emergency and Infection Diseases with presumed as CCHF between May 2010 and September 2010. Forty-one age and gender matched healthy individuals had not any viral, bacterial, acute or chronic disease were enrolled as the controls. Blood specimens were centrifuged at 4000 rpm for 5 min with in "Hettich universal 32" centrifuge. Serum samples obtained were kept at -80°C. All the specimens were brought to room temperature during the study and MMP-1, 2, 7, 9, 10 and TIMP-1 tests were studied at one time using "RayBiotech" brand kit in "Grifols" brand "Triturus" model ELISA device. Acute, convalescence and control groups were compared in terms of the serum levels of MMP-1, 2, 7, 9, 10 and TIMP-1.There was a statistically significant increase in serum levels of MMP-1, 7, 9, 10 and TIMP-1 in the convalescence period (p0.05) compared to the controls, while the increase in levels of MMP-2 was not statistically significant (p0.05). In acute period of CCHF, mean TIMP-1 levels of severe patients was significantly lower than that of the non-severe patients (207913 ± 31051 versus 231300 ± 13267, respectively, p = 0.023).High serum levels of MMP and TIMP in CCHF disease were found to decrease as progressed to convalescence from the acute period. It is thought MMP and TIMP plays a significant role in pathogenesis of CCHF.

In this paper, different axial gap permanent magnet generators are designed and compared for one of the Caterpillar truck applications. Various axial gap designs with multiple stators and rotors are carried out and compared with a conventional PM generator in terms of torque density, efficiency, loss, heat dissipation, volume, inertia and weight. The results reveal the advantages of axial gap generators over radial gap generators and that internal rotor double stator disc generator fits the hybrid electric traction application with the given specifications.

Length and level of exposure to electromagnetic fields (EMFs) is increasing in association with the widespread use of electrical and electronic devices and technological progress. The undesirable effects of extremely low frequency magnetic fields (ELF-MFs) on health have attracted considerable interest.Sixty-four four-month-old male Wistar rats divided into eight groups of eight rats each were used. Seven groups were exposed to varying dosages of manganese (Mn) and a 50 Hz magnetic field (MF) of approximately 1 mT, while the last group was set aside as the cage control group and not subjected to any procedure. This study was intended to investigate the interactions between the application of MF and Mn and the elements Ca, Zn, Mg, and P thought to be involved in caries, in rat teeth.Levels of Ca, Mg, Zn, and P in the experimental group rats were different to those in the control group.The results demonstrate that ELF-MF and Mn can have significant effects on levels of elements in rat teeth. Further experimental and epidemiological studies of ELF-MF and Mn are needed in order to evaluate their dental effects.

SynopsisThe watermark disease is caused by the bacterium Erwinia salicis. It affects six species of tree willow and of these the white willow (Salix alba) and certain of its varieties are particularly susceptible. Unusually for a bacterial disease, the pathogen only colonises the xylem tissues, which become discoloured as a result. Watermark causes severe losses in S. alba var. caerulea, the cricket bat willow, and in several Dutch clones of S. alba which have been widely planted in that country. Although numerous studies have been made of its epidemiology since the disease was first reported in 1924, the infection process remains clusive. Recent research, much of it unpublished, points to the widespread occurrence of symptomless infection, and the possible role of this in the transmission of disease through the propagating material.

Interior permanent magnet (IPM) synchronous machines are vulnerable to uncontrolled generator (UCG) faults at high speed that can damage the inverter. One approach to reducing this risk is to impose limits on the maximum machine back-emf voltage at top speed. This paper presents the results of a comparative design study that clarifies the nature and extent of the penalties imposed on the IPM machine metrics and performance characteristics as a result of imposing progressively tighter values of back-emf voltage limits. As an alternative to limiting back-emf and penalizing machine designs, this paper also investigates the effectiveness of the system-side protection approach to the same UCG fault problem.

This paper proposes a pneumatic pressure sensor along with a microprocessor-based signal processing and indicating instrument. A thin strip in the form of a cantilever is attached to a diaphragm facing a pneumatic medium on other side. The strip traverses through a pivoted hinge whenever pressure on the diaphragm is changing. The microprocessor excites the strip for producing mechanical oscillations, through an electromagnet and reads the oscillations of the strip from an optocoupler. The fundamental frequency of vibration is then estimated by software. As the frequency of oscillation depends on the length of the strip extending beyond the hinge, the microprocessor determines the instantaneous length of the strip and the pressure acting on the diaphragm, from the frequency measured. The proposed instrument has more sensitivity compared to the conventional pressure meters. Also, this has more durability compared to the previous vibrating wire transducer

This paper describes a new closed loop approach to estimate induction machine speed and rotor time constant from measured terminal voltages and currents for speed/torque sensorless control. For this purpose, a new state estimator, which eliminates flux information of the machine, is defined and a Lyapunov function is derived to determine speed and rotor resistance. The proposed algorithm is analyzed and verified experimentally.

In this study, a new sliding mode current observer is proposed for the flux and speed estimation of an induction machine. The flux estimation accuracy is guaranteed through the current observer, i.e. the error between the actual current and observed current converges to zero which guarantees the accuracy of the flux estimation. The rotor speed is then estimated by using the estimated flux and sliding functions. During this process Euler approximation is used for derivation. The resulting algorithm guarantees that the correct speed and rotor time constant estimation is possible even before the system trajectories reach the sliding manifold, which enables the correct estimation before the observed currents converges the measured values. The new approach is verified by simulation and experimental results, which show the robustness and performance of the proposed observer structure.

This paper presents flux and speed estimation with on-line rotor time constant estimation for an indirect field oriented induction motor drive system using sliding mode technique. A closed loop flux observer based on the current estimation error is constructed. A unique feature of the proposed observer is that, the proposed current observer includes a sliding mode function, which is derivative of the flux. Therefore, when the estimated current converges to the measured one, the sliding mode function is integrated to calculate the flux. The speed and rotor time constant can then be calculated from the sliding mode function and the estimated flux. Simulation and experimental results for the flux and speed estimation of the machine are presented to validate the proposed algorithm.

This paper presents a current model rotor flux observer based model reference adaptive control system (MRAS) scheme. The proposed MRAS scheme provides an attractive mean for achieving the rotor resistance adaptation for an indirect field oriented (IFO) induction motor drive system. The desired value of the rotor flux along the q-axis should ideally be zero. This condition acts as a reference model for the proposed MRAS scheme. The current model flux observer is an adjustable model. The machine parameters in the adjustable model are rotor inductance and resistance. Inductance does not change with temperature. Therefore, the only parameter which changes with temperature in the adjustable model is the rotor resistance. This resistance is adjusted such that the flux along the q-axis is driven to zero. The proposed method effectively adjusts the rotor resistance online and keeps the machine field oriented. The effectiveness of the proposed scheme is tested through simulation and is experimentally verified. Experimental results show that this scheme keeps the machine field oriented, provides faster and better speed/torque response and also improves the torque per amp output of the machine.

An adaptive parallel distributed compensator (APDC) using Takagi-Sugeno fuzzy systems for indirect field oriented (IFO) induction machines is proposed. An on-line method is used to adjust the parameters of a Takagi-Sugeno identifier model to match the behavior of IFO induction machine drive system. Then, using the certainty equivalence principle, the parameters of the Takagi-Sugeno identifier model are employed in a standard control design method for the standard parallel distributed compensator to provide a global asymptotically stable equilibrium for the closed loop IFO drive system. In this way, identifier does not need to have any initial knowledge about the IFO drive system and as the identifier becomes more accurate, the controller parameters of the parallel distributed compensator will be adjusted, and if the identifier succeeds in its task, the controller will too. The proposed controller is simulated for a 5 hp induction machine drive system. The comparison of the standard PI and APDC is presented by simulation as well. These results prove that the proposed controller is robust to load changes and system disturbances and can also follow different command trajectories very well without any re-tuning of the controller.

A Fuzzy Logic Controller (FLC), with a Dynamically Focussed Learning (DFL) algorithm is proposed, developed and implemented to improve the performance of an induction motor drive system. In standard direct fuzzy controller, utilization of the rule-base is mostly poor, especially when error input gets smaller and the control action is produced by only a few rules in the center of the rule-base. With such a small number of rules, the fuzzy controller performs inadequately because the resulting control surface can capture very approximate control actions. This poor utilization of the rule-base may degrade the controller performance. A possible solution to this problem may be to redesign the rule-base such that the rule base has move rules at the center. However, this solution limits the ability of the controller to a limited input range and specific inputs. Instead, a DFL fuzzy controller is proposed, which ensures that the fuzzy controller can utilize the entire rule base by auto-tuning algorithm. Computer simulation and experimental results on a 5 hp induction machine are presented to substantiate the proposed scheme.

In this paper a new sliding mode flux and speed observer is proposed for induction machine drive systems. The error between the actual and observed currents converges to zero which guarantees the accuracy of the flux observer. The rotor speed and the rotor time constant are estimated based on the estimated stator currents and rotor flux. The estimated rotor time constant is used in slip calculation and observer structures and the estimated speed is used as feedback to the speed regulation. Computer simulation results of the speed control verify the validity of the proposed speed estimation algorithm.

This paper has attempted to improve the speed control performance of an indirect field oriented (IFO) induction motor drive system by using a continuous sliding mode controller. The proposed continuous sliding mode controller is robust to load changes and system disturbances which are unique features of discontinuous sliding mode control. Also it is free from chattering which is the main problem of discontinuous sliding mode control. The proposed controller can also overcome the performance degradation and avoid tedious tuning process associated with the PI controller. The results of PI and sliding mode controller (SMC) are compared through extensive simulation and experimental work. These results prove that the proposed controller is robust to load changes and system disturbances and can also follow different command trajectories very well without re-tuning of the controller.

We have previously shown that the dithiocarbamate fungicide, Mancozeb, strongly induces lacZ reporter expression from an endogenous heat-shock promoter (hsp16) in the PC72 transgenic strain of the nematode Caenorhabditis elegans. Such evidence of organismal stress, in a nontarget species at subapplication concentrations, was much less apparent for the related fungicide, Maneb, which only weakly induced reporter expression. We now show that reporter induction by Mancozeb is marginal (60%) after a few hours' exposure, but increases substantially (to almost 10-fold) after overnight exposure. In conjunction with our previous results using intermediate exposure periods, this suggests that the factor limiting reporter responses is likely to be a slow rate of uptake and/or metabolism of the fungicide. We confirm that a potentially toxic metabolite of dithiocarbamate fungicides, namely ethylenethiourea (ETU), has minimal toxicity toward C. elegans, even after prolonged exposure at high concentrations. We demonstrate that exposure to Mancozeb (but not ETU) significantly inhibits larval growth in C. elegans, although this parameter is not markedly more sensitive than reporter induction as a toxicological endpoint. Finally, we have used two-dimensional electrophoresis to show that high concentrations of both Maneb and Mancozeb drastically simplify the protein spot profile compared with controls. However, only in the latter case is there evidence of novel proteins being induced. Both fungicides appear toxic to C. elegans, but only Mancozeb induces a strong heat-shock response.

In this paper, a new sliding mode flux and speed observer is proposed. The flux observer accuracy is guaranteed through the current observer. The error between the actual current and observed current converges to zero which guarantees the accuracy of the flux observer. The rotor speed is estimated by the observer based on the measured and estimated stator currents and estimated rotor flux. In addition, the command voltages are used rather then the measured ones. Therefore, in the proposed algorithm, only current sensors are needed. The new approach is verified by simulation and experimental results. The experimental results show the robustness and performance of the proposed observer structure.