490 research outputs found
A study of energy efficiency opportunities in Putrajaya Maritime Centre towards green building
Nowadays, people are more concerned about energy efficiency, energy
consumption and conservations in buildings. With this in view, a project to
investigate the potential of energy saving in selected building in Putrajaya Maritime
Centre was carried out. The scope of the study includes identifying energy
consumption in a selected building, to study energy saving opportunities, and to
analyse cost investment in term of economic. As a public building and a recreation
centre, these building should take the initiative to protect the environment towards
green building. According to the research and analysis, several solutions are
proposed to help reduce energy consumption and energy cost in the Maritime Centre.
First, by improving physical properties of building components. Second, by changing
the air condition temperature control setting. This paper also discuss about the
improvement of lighting system efficient. From the data analysis, it has been found
that huge amount of energy can be saved for a better green environment
The use of cement leftovers from the hollow of spun piles as an additive in self-compacting concrete
Spun piles have been used widely by developing countries, including Malaysia, to construct the foundation of most construction projects. A spun pile is a reinforced precast and prestressed concrete that is compacted in a mould through spinning compaction. The spinning compaction produces cement leftovers in the hollow part of spun piles that can be added to concrete mixtures as an additive. The cement leftovers of spun piles were used as an additive in cement in range of 0%, 10%, 20% and 30% (equal percentages). The resulting compressive strength after curing periods of 7 days and 28 days were presented to investigate the properties of self-compacting concrete containing cement leftovers from the spun piles. Other properties investigated include the physical properties of fresh concrete and water absorption. The results indicated that higher compressive strength and lower water absorption were achieved by the concrete samples containing cement leftovers compared to controlled concrete
Employability skills for hospitality students in Malaysia
Malaysia needs high skilled workforce to support growth of the industry. With dynamically changing job market and progressive technological change, employees are expected to keep abreast of global economics. In the process of achieving the status of developed nation by the year 2020, Malaysia needs to restructure its workforce to ensure that middle level workers are highly skilled. Current job environment demands multi-task and skills. Thus, university graduates must be prepared to meet the demand especially in the hospitality industry. The purpose of this study is to identify the level of employability skills in the hospitality field. This research applied quantitative methodology. The respondents consist of final year students in bakery and culinary programme. Stratified sampling was used to select students in hospitality programs from 22 vocational colleges in Malaysia. Questionnaires were distributed to 841 students in five regions which are Central, South, North, East and East Malaysia (Sarawak) in Malaysia. Descriptive analysis was used to analyse the quantitative data. The results showed that the level of hospitality employability skills among vocational students in Malaysia were at high level of competence (93.2%). The research has brought meaningful implications for hospitality vocational students, employers and policy makers
On the Modeling, Analysis and Development of PMSM: For Traction and Charging Application
Permanent magnet synchronous machines (PMSMs) are widely implemented commercially available traction motors owing to their high torque production capability and wide operating speed range. However, to achieve significant electric vehicle (EV) global market infiltration in the coming years, the technological gaps in the technical targets of the traction motor must be addressed towards further improvement of driving range per charge of the vehicle and reduced motor weight and cost. Thus, this thesis focuses on the design and development of a novel high speed traction PMSM with improved torque density, maximized efficiency, reduced torque ripple and increased driving range suitable for both traction and integrated charging applications. First, the required performance targets are determined using a drive cycle based vehicle dynamic model, existing literature and roadmaps for future EVs. An unconventional fractionalâslot distributed winding configuration with a coil pitch of 2 is selected for analysis due to their short endâwinding length, reduced winding losses and improved torque density. For the chosen baseline topology, a nonâdominated sorting genetic algorithm based selection of optimal odd slot numbers is performed for higher torque production and reduced torque ripple. Further, for the selected odd slotâpole combination, a novel starâdelta winding configuration is modeled and analyzed using winding function theory for higher torque density, reduced spatial harmonics, reduced torque ripple and machine losses. Thereafter, to analyze the motor performance with control and making critical decisions on interâdependent design parameter variations for machine optimization, a parametric design approach using a novel coupled magnetic equivalent circuit model and thermal model incorporating current harmonics for fractionalâslot wound PMSMs was developed and verified. The developed magnetic circuit model incorporates all machine nonâlinearities including effects of temperature and induced inverter harmonics as well as the space harmonics in the winding inductances of a fractionalâslot winding configuration. Using the proposed model with a pareto ant colony optimization algorithm, an optimal rotor design is obtained to reduce the magnet utilization and obtain maximized torque density and extended operating range. Further, the developed machine structure is also analyzed and verified for integrated charging operation where the machineâs winding inductances are used as line inductors for charging the battery thereby eliminating the requirement of an onâboard charger in the powertrain and hence resulting in reduced weight, cost and extended driving range. Finally, a scaledâdown prototype of the proposed PMSM is developed and validated with experimental results in terms of machine inductances, torque ripple, torqueâpowerâspeed curves and efficiency maps over the operating speed range. Subsequently, understanding the capabilities and challenges of the developed scaledâdown prototype, a fullâscale design with commercial traction level ratings, will be developed and analyzed using finite element analysis. Further recommendations for design improvement, future work and analysis will also be summarized towards the end of the dissertation
Efficiency Optimization and Control of Permanent Magnet Synchronous Brushless Motors in Three-Phase Pulse Width Modulated Voltage Source Inverter Drives
In high performance drives where it is desirable to exploit the usefulness of reluctance torque and machine saliency, permanent magnet synchronous brushless motors are machines of choice. However, speed control of these machines especially in the flux weakening region becomes more complex due to the non-linear coupling among the winding currents as well as the nonlinearity present in the torque. While numerous research efforts in the past have considered control and efficiency improvements of induction motors, and synchronous motors with field windings, research efforts in developing an efficiency optimization and control strategy applicable to all salient-type permanent magnet synchronous brushless motors are still in their infancy.;A traditional control technique that has commonly been employed in efficiency improvement efforts is the stator\u27s zero d-axis current (i ds=0) technique. In this method, the rotor flux is aligned with the direct-axis so that the stator\u27s direct-axis current is zero and the torque becomes a linear function of the stator\u27s quadrature-axis current. Although this method achieves decoupling of winding currents and simplicity of control, it does not fully exploit the use of the machine\u27s saliency and reluctance torque, and is also not well-suited for wide-range load operations. The maximum torque per ampere (MTPA) technique is another less complex technique that has been considered which fully exploits the use of machine saliency with motor torque selected along the geometric curve of minimum-amplitude current space vectors for minimum loss operation. The drawback of the MTPA technique is that it does not provide high efficiency performance for synchronous reluctance motors running at low fractional loads.;In this work, the problem of efficiency optimization in the salient-type permanent magnet synchronous brushless motors is investigated. A machine model which includes the effect of core losses is proposed for developing a loss minimization algorithm that dynamically determines the optimal reference currents and voltages required for minimizing the total electrical losses (copper losses and core losses) within the feasible operating regions imposed by the motor and inverter capacities. The loss minimization strategy is implemented within a speed control loop for a synchronous reluctance motor drive and the effectiveness of the proposed scheme is validated by comparing performances with that of the traditional maximum torque per ampere and stator\u27s zero d-axis current vector control methods. It is shown that the proposed scheme offers the advantages of simplicity and superior performance throughout the entire operating range, and also improves motor efficiency to 96% at full load and full-speed operating condition
Towards an improved energy efficiency of the interior permanent magnet synchronous motor drives
This paper investigates the possibility of energy efficiency increase in the
drives with high speed permanent magnet synchronous motors. The losses are
decreased by the proposed procedure, i.e. proper allocation of the available
stator current capacity to the direct and quadrature current components. The
approach provides increased energy efficiency by varying the ratio between
copper and iron losses. [Projekat Ministarstva nauke Republike Srbije, br. III042004
Pembangunan portal pendidikan teknik dan vokasional: satu kajian awal di kalangan Pelajar Sarjana PTV Jabatan Pendidikan Teknik dan Vokasional Fakulti Teknologi Kejuruteraan
Tujuan kajian ini adalah untuk mengkaji sejauh manakah keperJuan pelajar
terhadap portal Pendidikan Teknik dan Vokasional (PTV). Sebuah portal PTV
dibangunkan dalam kajian berasaskan produk ini. Sampel bagi kajian ini terdiri
daripada pelajar sarjana pendidikan teknik dan vokasional, semester 3. Dapatan kajian
ini dianalisis dengan menggunakan perisian SPSS versi 10. Pada peringkat awal projek
ini, keperluan pelajar terhadap portal PTV dikenal pasti. Selepas itu, ciri-ciri yang perlu
dibangunkan dalam portal PTV dikenal pasti dengan menggunakan kaedah borang soal
selidik. Satu portal PTV dibangunkan berdasarkan dapatan kajian tersebut. Pada
peringkat akhir projek ini, penilaian dilakukan ke atas portal PTV yang telah
dibangunkan. Tujuan penilaian ini adalah untuk mengenal pasti sejauh manakah portal
PTV ini memenuhi keperluan pelajar. Daripada dapatan kajian didapati portal PTV
amat diperlukan oleh pelajar. Selain daripada itu, daripada dapatan kajian, portal PTV
yang telah dibangunkan ini beryaya memenuhi keperluan pelajar. Cadangan untuk
memperbaiki portal PTV yang telah dibangunkan ini diberi oleh responden. Kajian
lanjutan patut dilakukan ke atas portal PTV yang telah dibangunkan bagi memperbaiki
serta memumikan konsep reka bentuk dan pengurusan maklumat
Development of an EV powertrain on system level by utilizing simulation-based design platforms
The challenges within electric powertrain design are managing multiple physics, time scales and spatial scales. There are existing methods available in different industries for modeling individual functional blocks of the electric powertrain. In this thesis a system level model of an electric vehicle (EV) powertrain is developed by examining different modeling and simulation methods. The final applications of an electrified powertrain can be for instance tractors, dumpers, harvesters and passenger cars. The target of the study is to provide modeling methods for evaluating energy efficiency and the performance of an electric powertrain. We focus on modeling a system including the battery, electric machine and a load.
This Masterâs thesis is done for EDR & Medeso oyâs Digital Electrification Laboratory (DEL) co-innovation project, which is a part of the e3Power project funded by Business Finland, that investigates the electrification of vehicles. The modeling and simulation are done in a digital platform using Ansys simulation software. Turku University of Applied Sciences eRallycross car project is used as a public reference for the modeling and simulation of the electric powertrain.
The thesis aims to divide the electric powertrain into functional blocks, analyze functional block models and to define generic functional block parameters for the implementation of a system representation. Developed models utilize actual physical measurements performed on the eRallycross car components. Electrical, thermal and mechanical performance of the electric powertrain is analyzed.
The study shows that it is possible to model and simulate a complex system that includes multiple physics and fidelities. The fidelity of each component model is adjustable and highly dependent of the input values available. Parameter ranges can be defined for individual component models. A main challenge of the study was the lack of component information from the manufacturers side.
The study represents the first trial of a development platform for modeling an electric powertrain on system level. During the DEL project the system model shall be further improved, so that the system model can enable reliability and efficiency improvements of existing electric powertrains, and structural or operational changes for future electric powertrain designs.SÀhköisten voimansiirtoketjujen mallien haasteita ovat eri fysiikoiden, aika- ja tila-alueiden hallitseminen. Eri aloilla on vallitsevia menetelmiÀ yksittÀisten sÀhköisten voimansiirtoketjujen komponenttien mallinnukseen. TÀssÀ tutkimuksessa kehitetÀÀn jÀrjestelmÀtason malli sÀhköisen ajoneuvon voimansiirtoketjusta tutkimalla eri mallinnus- ja simulointimenetelmiÀ. SÀhköistetyn voimansiirtoketjun sovellusalue voi olla esimerkiksi traktorit, dumpperit, puimurit ja henkilöautot. Työn tavoite on tarjota mallinnusmenetelmiÀ sÀhköisen voimansiirtoketjun energiatehokkuuden ja suorituskyvyn arviointiin. Keskitymme mallintamaan jÀrjestelmÀÀ, joka koostuu akustosta, sÀhkömoottorista ja kuormasta.
TĂ€mĂ€ diplomityö tehdÀÀn EDR & Medeso oy:n Digital Electrification Laboratory (DEL) projektille, joka on osa Business Finlandin rahoittamaa ePower projektia, jossa tutkitaan ajoneuvojen sĂ€hköistymistĂ€. Mallinnus ja simulointi suoritetaan digitaalisella alustalla kĂ€yttĂ€en Ansys â simulointiohjelmistoa. Turun ammattikorkeakoulun eRallycross projektia kĂ€ytetÀÀn julkisena viitteenĂ€ sĂ€hköisen voimansiirtoketjun mallinnuksissa ja simuloinneissa.
Tutkimus pyrkii jakamaan sÀhköisen voimansiirtoketjun komponenteiksi, analysoimaan komponenttien malleja ja mÀÀrittelemÀÀn geneerisiÀ komponenttien parametreja jÀrjestelmÀn esityksen toteuttamiseen. Kehitetyt mallit hyödyntÀvÀt fyysisiÀ mittaustuloksia, jotka suoritetaan eRallycross auton komponenteille. SÀhköisen voimansiirtoketjun sÀhköistÀ, termistÀ ja mekaanista suorituskykyÀ analysoidaan.
Tutkimus osoittaa, ettÀ on mahdollista mallintaa ja simuloida monimutkainen jÀrjestelmÀ, joka sisÀltÀÀ useampaa fysiikkaa sekÀ tarkkuustasoa. Jokaisen komponenttimallin tarkkuustaso on sÀÀdettÀvissÀ ja riippuvainen saatavilla olevista sisÀÀnmenoarvoista. Parametrien vaihteluvÀlit voidaan mÀÀritellÀ yksittÀisille komponenttimalleille. Tutkimuksen erÀs haaste oli komponenttitietojen puute valmistajien puolelta.
Tutkimus edustaa alustavaa suunnittelualustaa jÀrjestelmÀtason sÀhköisen voimansiirtoketjun suunnitteluun. DEL projektin aikana jÀrjestelmÀmallia parannetaan niin, ettÀ jÀrjestelmÀmalli mahdollistaa parannuksia olemassa olevien sÀhköisten voimansiirtoketjujen luotettavuudessa ja tehokkuudessa, sekÀ rakenteellisia ja toiminnallisia muutoksia tulevilla sÀhköisillÀ voimansiirtoketjumalleilla.Hantering av multifysik, olika tids- och rumsskalor tillhör utmaningarna av planeringen av elektriska drivlinor. Inom olika industrier finns det metoder för modelleringen av komponenter som tillhör elektriska drivlinor. I denna forskning utvecklas en system modell av en elektrisk fordons drivlina genom att utforska olika metoder kring modellering och simulering. TillÀmpningsomrÄden för elektriska drivlinor kan vara till exempel traktorer, dumprar, skördare och personbilar. MÄlet med detta diplomarbete Àr att presentera modelleringsmetoder för validering av energieffektivitet och prestation av en elektrisk drivlina. Vi fokuserar pÄ modellering av ett system som bestÄr av ett batteri, en elektrisk motor och en belastning.
Detta diplomarbete görs för EDR & Medeso ab:s Digital Electrification Laboratory (DEL) projekt, som tillhör Business Finlands finansierade e3Power projekt dĂ€r elektrifiering av fordon utforskas. Modellering och simulering utförs pĂ„ en virtuell platform av Ansys. Ă
bo yrkeshögskolans eRallycross projekt anvÀnds som en offentlig referens för modelleringen och simuleringen av den elektriska drivlinan.
Arbetet strÀvar till att dela upp den elektriska drivlinan i komponenter, analysera komponenterna och identifiera generella parametrar för komponenterna för skapandet av en representation av systemet. Utvecklade modellerna utnyttjar fysiska mÀtningar som gjorts pÄ eRallycross bilen. Elektriska, vÀrme och mekaniska effekter av den elektriska drivlinan analyseras.
Arbetet visar att det Àr möjligt att modellera och simulera ett komplext system, som inkluderar flera fysikomrÄden och noggranhetsnivÄer. NoggranhetsnivÄn för varje komponentmodell kan justeras och den Àr beroende av tillgÀngliga inputvÀrden. RÀckvidden för parametrarna kan defineras för individuella komponentmodeller. En av arbetets utmaningar var bristen pÄ komponent information frÄn tillverkarens sida.
Forskningen representerar ett basis av en utvecklingsplattform för modellering av en elektrisk drivlina pÄ systemnivÄ. Under DEL projektet förbÀttras system modellen pÄ sÄ vis, att system modellen möjlighetgör förbÀttring av pÄlitlighet och effektivitet av elektriska drivlinor, och strukturella och funktionella förÀndringar för framtida modeller av elektriska drivlinor
NOVEL MODELING, TESTING AND CONTROL APPROACHES TOWARDS ENERGY EFFICIENCY IMPROVEMENT IN PERMANENT MAGNET SYNCHRONOUS MOTOR AND DRIVE SYSTEMS
This thesis investigates energy efficiency improvement in permanent magnet synchronous motor (PMSM) and drive system to achieve highâperformance drive for practical industrial and primarily, traction applications. In achieving improved energy efficiency from a system level, this thesis proposes: (1) Accurate modeling and testing of loss components in PMSM considering inverter harmonics; (2) Easyâtoâimplement, accurate parameter determination techniques to understand variations in motor parameters due to saturation, crossâsaturation and temperature; and (3) Control methodologies to improve system level efficiency considering improved loss models and parameter variations. An improved loss model to incorporate the influence of motorâdrive interaction on the motor losses is developed by taking time and space harmonics into account. An improved winding function theory incorporating armature reaction fields due to fundamental and harmonic stator magnetic fields is proposed to calculate the additional harmonic losses in the PMSM. Once all contributing losses in the motor are modelled accurately, an investigation into control variables that affect the losses in the motor and inverter is performed. Three major control variables such as DC link voltage, switching frequency and current angle are chosen and the individual losses in the motor and inverter as well as the system losses are studied under varying control variables and wide operating conditions. Since the proposed loss as well as efficiency modeling involves machine operation dependent parameters, the effects of parameter variation on PMSM due to saturation and temperature variation are investigated. A recursive least square (RLS) based multiâparameter estimation is proposed to identify all the varying parameters of the PMSM to improve the accuracy and validity of the proposed model. The impact of losses on these parameters as well as the correct output torque considering the losses are studied. Based on the proposed loss models, parameter variations and the investigation into control variables, an offâline loss minimization procedure is developed to take into account the effects of parameter variations. The searchâbased procedure generates optimal current angles at varying operating conditions by considering maximization of system efficiency as the objective. In order to further simplify the consideration of parameter variations in realâtime conditions, an onâline loss minimization procedure using DC power measurement and loss models solved onâline using terminal measurements in a PMSM drive is proposed. A gradient descent searchâbased algorithm is used to calculate the optimal current angle corresponding to maximum system efficiency from the input DC power measurement and output power based on the loss models. During the thesis investigations, the proposed models and control techniques are extensively evaluated on a laboratory PMSM drive system under different speeds, load conditions, and temperatures
Multiobjective optimization of IPM synchronous motor using response surface methodology and filtered Monte Carlo approach
Permanent Magnet Synchronous Motors offer high efficiency and power density besides low assembly effort and hence have been established in a wide market over the past years. Especially buried magnets enable a superior field weakening ability but require an exceptional design effort. Costly Finite Elements computations are inevitable for consideration of the occurring non-linearity and non-trivial magnet shapes. The Response Surface Methodology can reduce the number of FE runs significantly by introducing an acceptably exact second order regression model based on a few carefully chosen design samples. Instead of commonly used, but time-consuming Evolutionary Strategy methods, the Monte Carlo approach is applied for optimization. Using simple filter algorithms, distinctive Pareto frontiers can be determined quickly and related to their causative motor designs
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