scholarly journals Multi-Level Modeling Methodology for Optimal Design of Electric Machines Based on Multi-Disciplinary Design Optimization

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4173
Author(s):  
Zehua Dai ◽  
Li Wang ◽  
Lexuan Meng ◽  
Shanshui Yang ◽  
Ling Mao
Keyword(s):  
Power Systems ◽  
Design Optimization ◽  
Synchronous Generator ◽  
Electric Machines ◽  
Modeling Method ◽  
System Level ◽  
Superior Performance ◽  
Efficient Design ◽  
Modeling Methodology ◽  
Multi Level

The transportation sector is undergoing electrification to gain advantages such as lighter weight, improved reliability, and enhanced efficiency. As contributors to the safety of embedded critical functions in electrified systems, better sizing of electric machines in vehicles is required to reduce the cost, volume, and weight. Although the designs of machines are widely investigated, existing studies are mostly complicated and application-specific. To satisfy the multi-level design requirements of power systems, this study aims to develop an efficient modeling method of electric machines with a background of aircraft applications. A variable-speed variable-frequency (VSVF) electrically excited synchronous generator is selected as a case study to illustrate the modular multi-physics modeling process, in which weight and power loss are the major optimization goals. In addition, multi-disciplinary design optimization (MDO) methods are introduced to facilitate the optimal variable selection and simplified model establishment, which can be used for the system-level overall design. Several cases with industrial data are analyzed to demonstrate the effectiveness and superior performance of the modeling method. The results show that the proposed practices provide designers with accurate, fast, and systematic means to develop models for the efficient design of aircraft power systems.

Multi-level Barriers for Utilization of Youth Friendly Reproductive Health Services (YFRHS) among Youths

2020 ◽  
Vol 8 ◽  
pp. 95-108
Author(s):  
Shanti Prasad Khanal
Keyword(s):  
Reproductive Health ◽  
Health Services ◽  
Health System ◽  
System Level ◽  
Mixed Method Research ◽  
Reproductive Health Services ◽  
Group Discussions ◽  
Personal Level ◽  
Multi Level ◽  
Youth Friendly

 The present study aims to examine the multi-level barriers to utilize by the youth-friendly reproductive health services (YFRHS) among the school-going youths of the Surkhet valley of Nepal. This study is based on the sequential explanatory research design under mixed-method research. The quantitative data were collected using the self- administered questionnaire from the 249 youths, aged between the 15-24 years, those selected by using random sampling. The qualitative data were collected using the Focus Group Discussions (FGDs) from the 12 participants who were selected purposively. The study confirmed that school-going youths do not have appropriate utilization of YFHS due to multi-layered barriers. However, the utilization of the service was higher among females, those the older age group, studying in the upper classes, the upper castes, and married youths. The key findings and themes are recognized as multi-layered barriers including personal-level, health system-level, community-level, and policy-level on the entire socio-ecological field. Among them, the existing health system is the foremost barrier. Multi-level interventions are, therefore, required to increase the YFRHS utilization and improve concerns for school-going-youths.  

scholarly journals Improved Immune Algorithm Combined with Steepest Descent Method for Optimal Design of IPMSM for FCEV Traction Motor

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3904
Author(s):  
Ji-Chang Son ◽  
Myung-Ki Baek ◽  
Sang-Hun Park ◽  
Dong-Kuk Lim
Keyword(s):  
Optimal Design ◽  
Permanent Magnet Synchronous Motor ◽  
Torque Ripple ◽  
Descent Method ◽  
Immune Algorithm ◽  
Electric Machines ◽  
Steepest Descent Method ◽  
Superior Performance ◽  
Element Analysis ◽  
Traction Motor

In this paper, an improved immune algorithm (IIA) was proposed for the torque ripple reduction optimal design of an interior permanent magnet synchronous motor (IPMSM) for a fuel cell electric vehicle (FCEV) traction motor. When designing electric machines, both global and local solutions of optimal designs are required as design result should be compared in various aspects, including torque, torque ripple, and cogging torque. To lessen the computational burden of optimization using finite element analysis, the IIA proposes a method to efficiently adjust the generation of additional samples. The superior performance of the IIA was verified through the comparison of optimization results with conventional optimization methods in three mathematical test functions. The optimal design of an IPMSM using the IIA was conducted to verify the applicability in the design of practical electric machines.

scholarly journals Opening Up Transactive Systems: Introducing TESS and Specification in a Field Deployment

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3970
Author(s):  
Marie-Louise Arlt ◽  
David P. Chassin ◽  
L. Lynne Kiesling
Keyword(s):  
Power Systems ◽  
Distribution System ◽  
Supply And Demand ◽  
System Level ◽  
Market Mechanisms ◽  
Bidding Strategies ◽  
Incentive Problems ◽  
Tariff Structures ◽  
Field Deployment ◽  
Residential Demand

Transactive energy systems (TS) use automated device bidding to access (residential) demand flexibility and coordinate supply and demand on the distribution system level through market processes. In this work, we present TESS, a modularized platform for the implementation of TS, which enables the deployment of adjusted market mechanisms, economic bidding, and the potential entry of third parties. TESS thereby opens up current integrated closed-system TS, allows for the better adaptation of TS to power systems with high shares of renewable energies, and lays the foundations for a smart grid with a variety of stakeholders. Furthermore, despite positive experiences in various pilot projects, one hurdle in introducing TS is their integration with existing tariff structures and (legal) requirements. In this paper, we therefore describe TESS as we have modified it for a field implementation within the service territory of Holy Cross Energy in Colorado. Importantly, our specification addresses challenges of implementing TS in existing electric retail systems, for instance, the design of bidding strategies when a (non-transactive) tariff system is already in place. We conclude with a general discussion of the challenges associated with “brownfield” implementation of TS, such as incentive problems of baseline approaches or long-term efficiency.

Adaptive Complex Method for Efficient Design Optimization

2007 ◽  
Author(s):  
Marcus Pettersson ◽  
Johan O¨lvander
Keyword(s):  
Design Optimization ◽  
Optimization Problem ◽  
Global Optimum ◽  
Direct Search ◽  
Complex Method ◽  
Efficient Design ◽  
Direct Search Methods ◽  
Simulation Based ◽  
Set Of Points ◽  
Quasi Newton

Box’s Complex method for direct search has shown promise when applied to simulation based optimization. In direct search methods, like Box’s Complex method, the search starts with a set of points, where each point is a solution to the optimization problem. In the Complex method the number of points must be at least one plus the number of variables. However, in order to avoid premature termination and increase the likelihood of finding the global optimum more points are often used at the expense of the required number of evaluations. The idea in this paper is to gradually remove points during the optimization in order to achieve an adaptive Complex method for more efficient design optimization. The proposed method shows encouraging results when compared to the Complex method with fix number of points and a quasi-Newton method.

scholarly journals 3D Photon-To-Digital Converter for Radiation Instrumentation: Motivation and Future Works

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 598
Author(s):  
Jean-François Pratte ◽  
Frédéric Nolet ◽  
Samuel Parent ◽  
Frédéric Vachon ◽  
Nicolas Roy ◽  
...  
Keyword(s):  
Large Scale ◽  
Single Photon ◽  
Time Of Flight ◽  
Digital Signal ◽  
Liquid Argon ◽  
Cmos Technology ◽  
System Level ◽  
Superior Performance ◽  
Digital Converter ◽  
Positron Emission

Analog and digital SiPMs have revolutionized the field of radiation instrumentation by replacing both avalanche photodiodes and photomultiplier tubes in many applications. However, multiple applications require greater performance than the current SiPMs are capable of, for example timing resolution for time-of-flight positron emission tomography and time-of-flight computed tomography, and mitigation of the large output capacitance of SiPM array for large-scale time projection chambers for liquid argon and liquid xenon experiments. In this contribution, the case will be made that 3D photon-to-digital converters, also known as 3D digital SiPMs, have a potentially superior performance over analog and 2D digital SiPMs. A review of 3D photon-to-digital converters is presented along with various applications where they can make a difference, such as time-of-flight medical imaging systems and low-background experiments in noble liquids. Finally, a review of the key design choices that must be made to obtain an optimized 3D photon-to-digital converter for radiation instrumentation, more specifically the single-photon avalanche diode array, the CMOS technology, the quenching circuit, the time-to-digital converter, the digital signal processing and the system level integration, are discussed in detail.

scholarly journals A Methodology for Provision of Frequency Stability in Operation Planning of Low Inertia Power Systems

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 737
Author(s):  
Michał Kosmecki ◽  
Robert Rink ◽  
Anna Wakszyńska ◽  
Roberto Ciavarella ◽  
Marialaura Di Somma ◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Flow ◽  
Storage System ◽  
Rate Of Change ◽  
System Level ◽  
Operation Planning ◽  
Planning Period ◽  
Power Sources ◽  
Real Time Digital Simulator

Along with the increasing share of non-synchronous power sources, the inertia of power systems is being reduced, which can give rise to frequency containment problems should an outage of a generator or a power infeed happen. Low system inertia is eventually unavoidable, thus power system operators need to be prepared for this condition. This paper addresses the problem of low inertia in the power system from two different perspectives. At a system level, it proposes an operation planning methodology, which utilises a combination of power flow and dynamic simulation for calculation of existing inertia and, if need be, synthetic inertia (SI) to fulfil the security criterion of adequate rate of change of frequency (RoCoF). On a device level, it introduces a new concept for active power controller, which can be applied virtually to any power source with sufficient response time to create synthetic inertia. The methodology is demonstrated for a 24 h planning period, for which it proves to be effective. The performance of SI controller activated in a battery energy storage system (BESS) is positively validated using a real-time digital simulator (RTDS). Both proposals can effectively contribute to facilitating the operation of low inertia power systems.

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