This paper proposes a method to minimize the cogging torque and torque ripple of an interior permanent magnet synchronous motor by adopting asymmetric barrier design and inverting lamination method. ...The analysis method for cogging torque and torque ripple is suggested using finite-element method. An asymmetric barrier in a permanent magnet rotor is optimally designed without permanent magnet skew. This proposed design for low cogging torque and torque ripple has an advantage over skew design from a manufacturing point of view. The proposed model is compared with the skew model and nonskew model by calculating torque characteristics to determine the more effective method to reduce torque distortion.
During the next 15 years, 40 million jobs need to be created each year in order to keep pace with population growth and foster greater participation of small and medium-sized enterprises (SMEs) in a ...globally integrated economy. Our paper proposes a new theory that integrates the sustainable use of natural resources, better use of produced capital, and further investment in human capital. Our new theory, Humane Entrepreneurship (HumEnt), encompasses three key research domains: Entrepreneurship, Leadership, and Human Resource Management. The HumEnt theory presents a new perspective on how to create 40 million quality jobs each year and helps address global challenges.
Review of maglev train technologies LEE, Hyung-Woo; KIM, Ki-Chan; LEE, Ju
IEEE transactions on magnetics,
07/2006, Volume:
42, Issue:
7
Journal Article
This paper reviews and summarizes Maglev train technologies from an electrical engineering point of view and assimilates the results of works over the past three decades carried out all over the ...world. Many researches and developments concerning the Maglev train have been accomplished; however, they are not always easy to understand. The purpose of this paper is to make the Maglev train technologies clear at a glance. Included are general understandings, technologies, and worldwide practical projects. Further research needs are also addressed.
This paper shows a study on the demagnetization performance analysis of permanent magnet according to three kinds of rotor types of an interior permanent magnet synchronous motor (IPMSM). It is very ...important to consider demagnetization performance as well as motor performance such as rated torque, output current, and efficiency when designing IPMSM. Three kinds of rotor types according to permanent magnet arrangement; single layer type, v shape type, and double layer type are generally used for IPMSM. In the paper, the magnetic equivalent circuits according to each rotor type are proposed in order for initial design of thickness of permanent magnets considering demagnetization by lumped constant related to magnetic circuit. The volume of permanent magnets per pole and back EMF of each rotor type is assumed to equal for the comparison of demagnetization of IPMSMs with same performance each other. Next, distribution of demagnetization in the permanent magnet is analyzed by using finite element method (FEM) for the verification of the results by magnetic equivalent circuit.
Despite the ongoing spread of MERS, there is limited knowledge of the factors affecting its severity and outcomes. We analyzed clinical data and specimens from fourteen MERS patients treated in a ...hospital who collectively represent a wide spectrum of disease severity, ranging from mild febrile illness to fatal pneumonia, and classified the patients into four groups based on severity and mortality. Comparative and kinetic analyses revealed that high viral loads, weak antibody responses, and lymphopenia accompanying thrombocytopenia were associated with disease mortality, whereas persistent and gradual increases in lymphocyte responses might be required for effective immunity against MERS-CoV infection. Leukocytosis, primarily due to increased neutrophils and monocytes, was generally observed in more severe and fatal cases. The blood levels of cytokines such as IL-10, IL-15, TGF-β, and EGF were either positively or negatively correlated with disease mortality. Robust induction of various chemokines with differential kinetics was more prominent in patients that recovered from pneumonia than in patients with mild febrile illness or deceased patients. The correlation of the virological and immunological responses with disease severity and mortality, as well as their responses to current antiviral therapy, may have prognostic significance during the early phase of MERS.
Variable reluctance (VR) resolver is widely used in traction motor for battery-powered electric vehicles (EVs), as well as for hybrid EVs as rotor position sensor. VR resolver generates absolute ...position signal using resolver-to-digital converter (RDC) to deliver the exact position of permanent magnets in the rotor of a traction motor to the motor controller. This paper deals with analysis methodology on a VR resolver using cosimulation analysis with RDC tracking algorithm for position-angle detection considering uneven magnetic fields. The eccentricity of the VR resolver, short-circuit conditions of the excitation and output-signal coils, and shape of rotor saliency are considered as sources of uneven magnetic fields in the VR resolver. Two-dimensional FEM is used for the SIN and COS output-signal waveforms, and these waveforms are converted into absolute position angle using RDC algorithm. To verify the analysis results of the proposed resolver, experiments on different uneven magnetic field conditions were conducted and compared with the simulation results.
This article aims to accomplish the output voltage tracking task for buck converters without current feedback, diminishing the performance degradation from model-plant mismatches and load variations. ...The following contributions overcome these difficulties: a) the combination of Luenberger and disturbance observer (DOB) techniques for a parameter-independent voltage-derivative observer; b) the pole-zero cancellation control incorporating the DOB and active-damping injection techniques; and c) the exponential convergence guarantee to the target tracking system subject to the variable convergence rate mechanism. Convincing experimental evidence confirms the effectiveness of proposed tracking control using a prototype 3 kW buck converter control system.
In this paper, a novel field weakening control method for permanent magnet synchronous motor is proposed to improve maximum speed range and maximum power, which are important parameters for electric ...vehicle application. Unlike general field weakening control method in which current vector is used to decrease linkage magnetic flux, the proposed method can decrease linkage magnetic flux by creating a difference gap between a stator and a rotor in axial direction without moving the current vector. This method is effective in increasing the maximum speed and the output power of permanent magnet synchronous motor, including surface permanent magnet-type rotor and interior permanent magnet-type rotor. Three-dimensional finite element method is adopted for the analysis of the proposed method in order to calculate d-axis and q-axis inductances as well as linkage magnetic flux according to axial gap. Motor performances according to speed are also compared with one another.
The proposed surface stabilization technique based filter feedbacks the filtering error with its nonlinear variable gain algorithm in order to recover the source signal information rejecting the ...high-frequency component (e.g., low-pass filtering), thereby guaranteeing closed-loop stability. Thus, resultant implementation is possible without signal dynamics information. The result provides two contributions: first, the improvement of the transient filtering performance through the closed-form feedback gain magnification mechanism and second, the recovery of the exponential filtering performance due to the surface stabilization mechanism, including the exponential convergent disturbance estimator originated from the nonlinear disturbance observer. The experimental results verify the effectiveness of the proposed technique, which improves the 500-W three-phase motor control performance.
This paper presents a practical architecture for fully exploiting the scalability of modular multilevel converters (MMC) by clustering the submodules (SMs) and interleaving these clusters. The ...proposed architecture enables scalability and flexibility for various high-voltage applications by dividing the computing tasks of an arm controller among each cluster control iteration, interleaving the output voltages of each cluster to maintain the desired voltage quality without structural changes, and balancing the cluster energy to ensure stable control performance. One noteworthy aspect of the proposed architecture is its implementation of distributed cluster control using a single controller, which eliminates the need for inter-controller synchronization and utilizes hardware resources cost-effectively. The paper provides design guidelines for clustering the SMs through theoretical analysis and numerical examples. The validity and performance of the proposed interleaving scheme for the clusters of SMs are demonstrated through hardware-in-the-loop simulation (HILS).
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