High Specific Power Electrical Machines: A System Perspective

There has been a growing need for high specific power electrical machines for a wide range of applications. These include hybrid/electric traction applications, aerospace applications and Oil and Gas applications. A lot of work has been done to accomplish significantly higher specific power electrical machines especially for aerospace applications. Several machine topologies as well as thermal management schemes have been proposed. Even though there has been a few publications that provided an overview of high-speed and high specific power electrical machines [1-3], the goal of this paper is to provide a more comprehensive review of high specific power electrical machines with special focus on machines that have been built and tested and are considered the leading candidates defining the state-of-the art. Another key objective of this paper is to highlight the key “system-level” tradeoffs involved in pushing electrical machines to higher specific power. Focusing solely on the machine specific power can lead to a sub-optimal solution at the system-level

Analysis of AC link topologies in non-isolated DC/DC triple active bridge converter for current stress minimization

This paper presents analysis of the non-isolated DC/DC triple active bridge (TAB) converter under various purely inductor-based AC link topologies. The objective of the analysis is to find the topology that incorporates the least value of the AC link inductors which leads to reduced converter footprint in addition to minimum internal current stresses. Modelling of the TAB under each of the different topologies is presented in per unit expressions of power transfer and reactive power assuming fundamental harmonic analysis. The power expressions are used to calculate the inductor values necessary to achieve same rated power transfer of Dual Active Bridge (DAB) converter for the sake of standardizing comparison. On this basis, the topology requiring the least value of interface inductors, hence lowest footprint, is identified. Furthermore, based on phase shift control, particle swarm optimization (PSO) is used to calculate optimal phase shift ratios in each of the proposed topologies to minimize reactive power loss (hence current stress). The topology with minimum stresses is therefore identified and the results are substantiated using a Matlab-Simulink model to verify the theoretical analysis

Generic closed loop controller for power regulation in dual active bridge DC-DC converter with current stress minimization

This paper presents a comprehensive and generalized analysis of the bidirectional dual active bridge (DAB) DC/DC converter using triple phase shift (TPS) control to enable closed loop power regulation while minimizing current stress. The key new achievements are: a generic analysis in terms of possible conversion ratios/converter voltage gains (i.e. Buck/Boost/Unity), per unit based equations regardless of DAB ratings, and a new simple closed loop controller implementable in real time to meet desired power transfer regulation at minimum current stress. Per unit based analytical expressions are derived for converter AC RMS current as well as power transferred. An offline particle swarm optimization (PSO) method is used to obtain an extensive set of TPS ratios for minimizing the RMS current in the entire bidirectional power range of - 1 to 1 per unit. The extensive set of results achieved from PSO presents a generic data pool which is carefully analyzed to derive simple useful relations. Such relations enabled a generic closed loop controller design that can be implemented in real time avoiding the extensive computational capacity that iterative optimization techniques require. A detailed Simulink DAB switching model is used to validate precision of the proposed closed loop controller under various operating conditions. An experimental prototype also substantiates the results achieved

Image findings of cranial nerve pathology on [18F]-2- deoxy-D-glucose (FDG) positron emission tomography with computerized tomography (PET/CT): a pictorial essay.

This article aims to increase awareness about the utility of (18)F -FDG-PET/CT in the evaluation of cranial nerve (CN) pathology. We discuss the clinical implication of detecting perineural tumor spread, emphasize the primary and secondary (18)F -FDG-PET/CT findings of CN pathology, and illustrate the individual (18)F -FDG-PET/CT CN anatomy and pathology of 11 of the 12 CNs

Clinical and financial evaluation of patients within a diagnosis related group

The purpose of this study is to evaluate financial and clinical data of patients within a selected DRG. The data obtained from such analysis will be used to design a system whereby clinical pharmacists may improve the hospital\u27s reimbursement potential. Based upon Upton\u27s proposed plan, this study is designed to evaluate all DRGs in a community hospital in an attempt to focus on those DRGs which represent the greatest financial pressure to the pharmacy department and, therefore, to the institution. Clinical and financial data of patients within the expensive DRG, will be collected from their medical and financial records for subsequent statistical analysis with special consideration to pharmacy charges. The ultimate objective of this study, though, is to provide a list of measures or parameters that may affect the patient\u27s hospital charges. Using these parameters, the clinical pharmacists will be able to intensify their monitoring of patients with high pharmacy charges in an attempt to reduce their impact on patients\u27 charges. This study was designed to review and analyze DRGs at St. Joseph\u27s Hospital, in Stockton, Californias. The main objective was to determine the relationship between clinical and financial data for patients within a DRG. The second objective was to identify patient-specific information that may reflect high pharmacy charges and the need for clinical pharmacy intervention. The third objective was to propose criteria that may predict which patients need to be monitored in an attempt to control pharmacy charges within a selected DRG category

Hirschman optimal transform least mean square adaptive filters.

Abstract not available