Economical potential of controlling charging of electric vehicles by using price signal

The number of electric vehicles grows continuously and the implementation of charging electric vehicles is an important issue for the future. Increasing amount of electric vehicles can cause problems to distribution grid by increasing peak load. Currently charging of electric vehicles is uncontrolled, but as the amount of electric vehicles grows, smart charg-ing (controlled charging) will be one possible solution to handle this situation. In this thesis smart charging of electric vehicles is examined from electricity retailers` point of view. The purpose is to find out plausible saving potentials of smart charging, when it´s controlled by price signal. Saving potential is calculated by comparing costs of price signal controlled charging and uncontrolled charging.

[Air de Laodice]

Soitinnus: lauluääni (sopraano), piano.

Individual learner, peer group and teacher roles in fostering autonomous language-learning behaviour

Julkaisumaa: Bulgaria

Cost Reduction of Permanent Magnet Synchronous Machines

Electrical machine drives are the most electrical energy-consuming systems worldwide. The largest proportion of drives is found in industrial applications. There are, however many other applications that are also based on the use of electrical machines, because they have a relatively high efficiency, a low noise level, and do not produce local pollution. Electrical machines can be classified into several categories. One of the most commonly used electrical machine types (especially in the industry) is induction motors, also known as asynchronous machines. They have a mature production process and a robust rotor construction. However, in the world pursuing higher energy efficiency with reasonable investments not every application receives the advantage of using this type of motor drives. The main drawback of induction motors is the fact that they need slipcaused and thus loss-generating current in the rotor, and additional stator current for magnetic field production along with the torque-producing current. This can reduce the electric motor drive efficiency, especially in low-speed, low-power applications. Often, when high torque density is required together with low losses, it is desirable to apply permanent magnet technology, because in this case there is no need to use current to produce the basic excitation of the machine. This promotes the effectiveness of copper use in the stator, and further, there is no rotor current in these machines. Again, if permanent magnets with a high remanent flux density are used, the air gap flux density can be higher than in conventional induction motors. These advantages have raised the popularity of PMSMs in some challenging applications, such as hybrid electric vehicles (HEV), wind turbines, and home appliances. Usually, a correctly designed PMSM has a higher efficiency and consequently lower losses than its induction machine counterparts. Therefore, the use of these electrical machines reduces the energy consumption of the whole system to some extent, which can provide good motivation to apply permanent magnet technology to electrical machines. However, the cost of high performance rare earth permanent magnets in these machines may not be affordable in many industrial applications, because the tight competition between the manufacturers dictates the rules of low-cost and highly robust solutions, where asynchronous machines seem to be more feasible at the moment. Two main electromagnetic components of an electrical machine are the stator and the rotor. In the case of a conventional radial flux PMSM, the stator contains magnetic circuit lamination and stator winding, and the rotor consists of rotor steel (laminated or solid) and permanent magnets. The lamination itself does not significantly influence the total cost of the machine, even though it can considerably increase the construction complexity, as it requires a special assembly arrangement. However, thin metal sheet processing methods are very effective and economically feasible. Therefore, the cost of the machine is mainly affected by the stator winding and the permanent magnets. The work proposed in this doctoral dissertation comprises a description and analysis of two approaches of PMSM cost reduction: one on the rotor side and the other on the stator side. The first approach on the rotor side includes the use of low-cost and abundant ferrite magnets together with a tooth-coil winding topology and an outer rotor construction. The second approach on the stator side exploits the use of a modular stator structure instead of a monolithic one. PMSMs with the proposed structures were thoroughly analysed by finite element method based tools (FEM). It was found out that by implementing the described principles, some favourable characteristics of the machine (mainly concerning the machine size) will inevitable be compromised. However, the main target of the proposed approaches is not to compete with conventional rare earth PMSMs, but to reduce the price at which they can be implemented in industrial applications, keeping their dimensions at the same level or lower than those of a typical electrical machine used in the industry at the moment. The measurement results of the prototypes show that the main performance characteristics of these machines are at an acceptable level. It is shown that with certain specific actions it is possible to achieve a desirable efficiency level of the machine with the proposed cost reduction methods.

Characterization of amine-based CO2 adsorbent for Direct Air Capture

Direct air capture technologies extract CO2 from air at a concentration of as low as 400ppm. The captured CO2 can be used for the production of synthetic methane or liquid fuels. In the literature survey of this thesis, results related to direct air capture by using solid sorbents are presented and critically discussed. In the experimental part, a proprietary amine functionalized resin is characterized for direct air capture. Structural comparison is also made to a commercial resin of similar type. Based on the literature survey, the most important parameters in direct air capture process are low adsorption and desorption temperatures, good cyclic stability in dry and humid conditions, high CO2 outlet purity and a high working capacity. Primary amine functionalized solid sorbents are found to often have good qualities for direct air capture, but overall process performance is rarely studied exhaustively. Based on FTIR spectra, both resin adsorbents are found to be consisted of polystyrene functionalized with primary amine, and capture CO2 by forming carbamate. The commercial resin is more porous, has a slightly higher particle size and contains fewer impurities. Important physical parameters are gained of the proprietary resin, such as internal porosity and median particle size. The resin’s amine group is found to endure thermal treatment reasonably well. CO2 adsorption capacity gained by thermal gravimetry from 400ppm CO2 is highest at 25oC, and is found to be reasonable compared to values presented in literature. Thus, the resin is stated to exhibit promising qualities for direct air capture.

Piirilevyn suunnittelu suurelle virralle DC/DC-muuntimeen

Ajoneuvoissa, kuten busseissa, käytetään yleensä 24 VDC järjestelmiä ja tämä ei muutu myöskään sähköajoneuvojen kohdalla. Sähköajoneuvoissakin tarvitaan siis 24 VDC matalajänniteakustoja valoille, pyyhkijöille ja muille matalan jännitteen järjestelmille. Lisäksi sähköajoneuvoissa on esimerkiksi ilmastointi ja paineilmankompressori, jotka tarvitsevat taajuusmuuttajan pyörittämään niitä. Tässä työssä suunnitellaan suuren virran piilevy DC/DC-muuntimeen, joka on osa ajoneuvokäyttöön suunnitellun invertterin ja DC/DC-muuntimen yhdistelmälaitetta. Työn pääpaino on piirilevyn suunnittelussa, mutta työssä kerrotaan lyhyesti koko laitteen kytkentä ja käyttötarkoitus. Työssä kerrotaan myös tehopiirilevylle tulevien komponenttien valinta, mitoitus ja jäähdytys. Käydään läpi suuren virran piirilevysuunnittelun mitoitusperiaatteet ja mitä seikkoja siinä erityisesti tulee ottaa huomioon. Lisäksi käsitellään piirilevyn liityntöjä ja virtakiskojen lämpenemää virranahtautumisen takia. Suunniteltua piirilevyä mitataan ja sen toimintaa kokeillaan prototyyppilaitteessa. Protoyyppilaitteella havaitaan virtakiskojen lämpenevän liikaa ja huomataan ongelma kytkenssä. Kytkentää korjattiin ja toimintaa analysoitiin uudestaan, jonka jälkeen havaittiin piirilevyn lämpenemän tippuneen 20 °C. Lopputuloksena piirilevyn lämpenemä, korjatulla kytkennällä, on suunnitellun mukainen. Lopussa esitetään piirilevyn korvaamista moduuliratkaisulla laitteen parantamiseksi sarjatuotantoon.

Air-Sea Battle -konsepti John Wardenin Enemy as a System -teorian näkökulmasta

Tutkielman tavoitteena oli analysoida Air-Sea Battle -konseptia ja sen lähtökohtana ollutta viholliskuvaa John Wardenin Enemy as a System -teorian näkökulmasta julkisten asiakirjojen, raporttien ja artikkeleiden avulla. Tutkimusmenetelmänä on käytetty teoriaohjaavaa sisällönanalyysia. Tutkimusongelmaksi muodostui: ”Miten Air-Sea Battle -konsepti näyttäytyy Wardenin Enemy as a System -teorian näkökulmasta?” Tutkimuskysymyksien avulla pyrittiin lisäksi löytämään konseptin kehittämiseen johtaneita tekijöitä suurstrategisella tasolla, arvioimaan konseptin mukaista aseellisen voiman käyttöä sekä analysoimaan konseptia suhteessa Wardenin näkemyksiin sotilasstrategiasta. Wardenin Enemy as a System -teoria on esitelty tutkielman alkupuolella hyödyntäen alkuperäistekstejä, aiheesta kirjoitettuja tutkimuksia ja artikkeleita sekä sotataidollista kirjallisuutta. Air-Sea Battle -konseptia käsittelevän luvun aineisto on luokiteltu Wardenin neljän strategisen kysymyksen teemojen, eli tavoitteen, vaikuttamisen kohteiden, keinojen ja irtautumisen, mukaisesti. Tärkeimmät lähteet varsinaisen Air-Sea Battle -asiakirjan lisäksi olivat Yhdysvaltojen turvallisuus- ja sotilasstrategiaa määrittelevät dokumentit, tutkimuslaitosten julkaisemat raportit sekä aikakauslehtiartikkelit. Aineiston perusteella Yhdysvallat näkee tiettyjen valtioiden, kuten Kiinan, kehittyvät niin kutsutut anti-access/area denial -suorituskyvyt uhkana alueelliselle tasapainolle ja heidän kyvylleen ylläpitää sotilaallista läsnäoloa strategisesti merkittävillä alueilla. Air-Sea le -konseptin tavoitteena on määritellä ja kehittää suorituskyvyt, operatiiviset suunnitelmat ja toimintamallit, joiden mukaan toimivalla joukolla kyetään luomaan riittävä pelotevaikutus konfliktin ehkäisemiseksi tai säilyttämään toiminnanvapaus alueella sen muodostuessa.

Air defence in Northern Europe

Finnish Defence Studies is published under the auspices of the National Defence College, and the contributions reflect the fields of research and teaching of the College. Finnish Defence Studies will occasionally feature documentation on Finnish Security Policy. Views expressed are those of the authors and do not necessarily imply endorsement by the National Defence College.

Sähköautojen akkuteknologioiden tilannekatsaus

Tämän kandidaatintyön tavoitteena oli tutkia sähköautoissa käytettäviä akkuteknologioita ja verrata niiden ominaisuuksia keskenään sekä sähköautojen asettamien akkuvaatimusten kanssa. Akkuteknologiakartoituksen ja ominaisuusvertailun avulla tutkimuksessa oli tarkoitus selvittää sähköautojen akkujen kehitystä menneestä nykyhetkeen ja luoda katsaus akkuteknologian tulevaisuuteen. Tutkimuksessa painotettiin akkujen suorituskykynäkökulmaa, mutta tutkimuksessa otettiin kantaa myös eri akkuteknologioiden turvallisuuteen, ympäristötekijöihin ja hintaan. Työ toteutettiin kirjallisuustutkimuksena ja lähteinä käytettiin alan kirjallisuutta, IEEE artikkeleita, tutkimusraportteja ja verkkodokumentteja. Lisäksi tutkimuksessa hyödynnettiin akku- ja sähköautovalmistajilta saatavaa tietoa, johon suhtauduttiin varauksin. Tutkimuksessa kävi ilmi, että erilaisia litiumioniakkuteknologioita käytetään tällä hetkellä eniten sekä täyssähköautoissa että pistokehybrideissä. Huomattiin, että akkujen suorituskyvyn kehittyminen on nopeutunut viime vuosina. Erityisesti akkujen energianvarastointikykyyn vaikuttavat ominaisenergiatasot ovat kasvaneet selkeästi. Nykyisen kehittyneen litiumioniakkuteknologian todettiin täyttävän jo osittain lähivuosien suorituskykytavoitteet. Tutkimuksessa tultiin siihen tulokseen, että litiumrikkiakkuteknologia voi korvata litiumioniakkuteknologian ainakin täyssähköautoissa parempien ominaisenergiatasojen ja halvempien valmistuskustannuksien takia. Myös litiumilma-akkuteknologialla havaittiin olevan mahdollisuuksia haastaa muut litiumakkuteknologiat seuraavalla vuosikymmenellä. Tutkimuksen johtopäätöksenä todetaan, että sähköautot voivat kaupallistua laajemmin lähivuosina akkujen suorituskykyominaisuuksien kehittyessä jatkuvasti. Suorituskykyominaisuuksien parantuminen tulee todennäköisesti johtamaan siihen, että täyssähköautot yleistyvät enemmän ja pistokehybridit tulevat jäämään sähköautojen välivaiheeksi. Uusien akkuteknologioiden käyttöönotto kaupallisiin sähköautoihin voi viedä kuitenkin odotettua kauemmin, sillä akut tarvitsevat huolellista testausta ja käyttöönotto edellyttää, että kaikki ominaisuudet ovat vaaditulla tasolla.

A service perspective to digital innovation: exploring the emergence of autonomous shipping

Current research describes digital innovation largely similar to product innovation. Digital innovation is seen as an object of coherent activities, however in reality digital innovation results from convergence of variant technologies and those related actors with versatile business goals. To account for the dynamic nature of digital innovation, this study applies a service perspective to digital innovation. The purpose of the study is to understand how digital innovation emerges within a service ecosystem for autonomous shipping. The sub-objectives of this study are to 1) identify what factors motivate and demotivate actors to integrate resources for autonomous shipping, 2) explore the key technology areas to be integrated to realise the autonomous shipping concept, and 3) suggest how the technology areas are combined for mutual value creation within a service eco-system for autonomous shipping. Insights from autonomous driving were also included. This study draws on literatures on service innovation and service-dominant logic. The research was conducted as a qualitative exploratory case study. The data comprise interviews of 18 marine and automotive industry experts, 4 workshops, 4 seminars, and observations as well as various secondary data sources. The findings revealed that the key actors have versatile motivations regarding autonomous shipping. These varied from opportunities for single applications to occupying a central role in an autonomous technology platform. Thus, autonomous shipping can be seen as an umbrella concept comprising multiple levels. In technical terms, the development of the concept of autonomous shipping is largely based on combining existing technology solutions, which are gradually integrated towards more systemic entities comprising areas of the autonomous shipping concept. This study argues that a service perspective embraces the inherently complex and dynamic nature of digital innovation. This is captured in the developed research framework that describes digital innovation emerging on different levels of interaction: 1. strategic relationships for new solutions, 2. new local networks for technology platforms, and 3. global networks for new markets. The framework shows how the business models and motivations of digital innovation actors feed the emergence of digital innovation in overlapping service ecosystems that together comprise an innovation ecosystem for autonomous technologies. Digital innovation managers will benefit from seeing their businesses as part of a larger ecosystem of value co-creating actors. In orchestrating digital innovation within a service ecosystem, it is suggested that managers consider the resources, roles and institutions within the ecosystem. Finally, as autonomous shipping is at its infancy, the topic provides a number of interesting avenues for future research.

Natural freeze crystallization : purification of aqueous Na2SO4 solutions with cold air

The aim of this thesis was to examine efficiency of freeze crystallization and eutectic freeze crystallization in purification of wastewater by imitating natural freezing. In addition, a mathematic model based on heat transfer to determine ice thickness and ice growth rate was examined. Also, the amount of sodium sulfate crystallized at the eutectic point was under investigation. In literature part, advantages and applications of the freeze crystallization are discussed, and possibility to apply it in Northern hemisphere winter weather conditions is under study. Furthermore, main sources of sodium sulfate from Finnish industries are described. The experiments were carried out in modified chest freezer, where a fan was placed in order to obtain laminar air flow inside. Picolog PT-104 data logger was used to monitor temperature changes in the salt-water solution, and constant temperature was maintained in the crystallizer with Lauda RP 850 thermostat. The impurity of formed ice layer was determined by weighing ice samples after experiment and again after 24 hours drying to full dryness in oven. Volume of salt-water solution was also measured after experiment. The highest purity of formed ice layer was obtained with small temperature difference and with long freezing time. On the other hand, the amount of crystallized sodium sulfate was its greatest with long freezing time and higher temperature difference. The results obtained by the mathematic model and empirical results did not differ significantly in most of the experiments. However, the difference increased when salt-water mixture reached its eutectic point, leading to simultaneous ice and salt crystallization. Eutectic point was reached only with the highest salt concentration with one exception. In these cases, calculated values were in many cases greater than the experimental ones. In winter weather conditions freeze crystallization is cost-effective wastewater treatment method and rather simple. Nonetheless, the efficiency and separation rate are strongly depended on ambient temperature and its changes

Real-time simulation of multibody systems with applications for working mobile vehicles

This dissertation describes an approach for developing a real-time simulation for working mobile vehicles based on multibody modeling. The use of multibody modeling allows comprehensive description of the constrained motion of the mechanical systems involved and permits real-time solving of the equations of motion. By carefully selecting the multibody formulation method to be used, it is possible to increase the accuracy of the multibody model while at the same time solving equations of motion in real-time. In this study, a multibody procedure based on semi-recursive and augmented Lagrangian methods for real-time dynamic simulation application is studied in detail. In the semirecursive approach, a velocity transformation matrix is introduced to describe the dependent coordinates into relative (joint) coordinates, which reduces the size of the generalized coordinates. The augmented Lagrangian method is based on usage of global coordinates and, in that method, constraints are accounted using an iterative process. A multibody system can be modelled as either rigid or flexible bodies. When using flexible bodies, the system can be described using a floating frame of reference formulation. In this method, the deformation mode needed can be obtained from the finite element model. As the finite element model typically involves large number of degrees of freedom, reduced number of deformation modes can be obtained by employing model order reduction method such as Guyan reduction, Craig-Bampton method and Krylov subspace as shown in this study The constrained motion of the working mobile vehicles is actuated by the force from the hydraulic actuator. In this study, the hydraulic system is modeled using lumped fluid theory, in which the hydraulic circuit is divided into volumes. In this approach, the pressure wave propagation in the hoses and pipes is neglected. The contact modeling is divided into two stages: contact detection and contact response. Contact detection determines when and where the contact occurs, and contact response provides the force acting at the collision point. The friction between tire and ground is modelled using the LuGre friction model, which describes the frictional force between two surfaces. Typically, the equations of motion are solved in the full matrices format, where the sparsity of the matrices is not considered. Increasing the number of bodies and constraint equations leads to the system matrices becoming large and sparse in structure. To increase the computational efficiency, a technique for solution of sparse matrices is proposed in this dissertation and its implementation demonstrated. To assess the computing efficiency, augmented Lagrangian and semi-recursive methods are implemented employing a sparse matrix technique. From the numerical example, the results show that the proposed approach is applicable and produced appropriate results within the real-time period.

Small teleoperated vehicles: study of potential use cases and empirical prototyping

This thesis researches the current state of small teleoperated devices, the need for them and developing one. Small teleoperated devices give the possibility to perform tasks that are impossible or dangerous for humans. This work concentrates on small devices and cheap components and discloses one way of developing a teleoperated vehicle, but not necessarily the optimal way. Development and the current state of teleoperation were studied by a literature review, in which the data was searched from literature as well as from the Internet. The need for teleoperated devices was mapped through a survey, where 11 professionals from variating fields were interviewed how they could utilize a teleoperated devices and with what kind of features. Also, a prototype was built as a proof of concept of small teleoperated devices. The prototype is controlled by a single-board microcomputer that also streams video to the controlling device. The video can be viewed on a display or with a head mounted display.