Lightweight, liquid-cooled, direct-drive generator for highpower wind turbines: motivation, concept, and performance

Thesis: A liquid-cooled, direct-drive, permanent-magnet, synchronous generator with helical, double-layer, non-overlapping windings formed from a copper conductor with a coaxial internal coolant conduit offers an excellent combination of attributes to reliably provide economic wind power for the coming generation of wind turbines with power ratings between 5 and 20MW. A generator based on the liquid-cooled architecture proposed here will be reliable and cost effective. Its smaller size and mass will reduce build, transport, and installation costs. Summary: Converting wind energy into electricity and transmitting it to an electrical power grid to supply consumers is a relatively new and rapidly developing method of electricity generation. In the most recent decade, the increase in wind energy’s share of overall energy production has been remarkable. Thousands of land-based and offshore wind turbines have been commissioned around the globe, and thousands more are being planned. The technologies have evolved rapidly and are continuing to evolve, and wind turbine sizes and power ratings are continually increasing. Many of the newer wind turbine designs feature drivetrains based on Direct-Drive, Permanent-Magnet, Synchronous Generators (DD-PMSGs). Being low-speed high-torque machines, the diameters of air-cooled DD-PMSGs become very large to generate higher levels of power. The largest direct-drive wind turbine generator in operation today, rated just below 8MW, is 12m in diameter and approximately 220 tonne. To generate higher powers, traditional DD-PMSGs would need to become extraordinarily large. A 15MW air-cooled direct-drive generator would be of colossal size and tremendous mass and no longer economically viable. One alternative to increasing diameter is instead to increase torque density. In a permanent magnet machine, this is best done by increasing the linear current density of the stator windings. However, greater linear current density results in more Joule heating, and the additional heat cannot be removed practically using a traditional air-cooling approach. Direct liquid cooling is more effective, and when applied directly to the stator windings, higher linear current densities can be sustained leading to substantial increases in torque density. The higher torque density, in turn, makes possible significant reductions in DD-PMSG size. Over the past five years, a multidisciplinary team of researchers has applied a holistic approach to explore the application of liquid cooling to permanent-magnet wind turbine generator design. The approach has considered wind energy markets and the economics of wind power, system reliability, electromagnetic behaviors and design, thermal design and performance, mechanical architecture and behaviors, and the performance modeling of installed wind turbines. This dissertation is based on seven publications that chronicle the work. The primary outcomes are the proposal of a novel generator architecture, a multidisciplinary set of analyses to predict the behaviors, and experimentation to demonstrate some of the key principles and validate the analyses. The proposed generator concept is a direct-drive, surface-magnet, synchronous generator with fractional-slot, duplex-helical, double-layer, non-overlapping windings formed from a copper conductor with a coaxial internal coolant conduit to accommodate liquid coolant flow. The novel liquid-cooling architecture is referred to as LC DD-PMSG. The first of the seven publications summarized in this dissertation discusses the technological and economic benefits and limitations of DD-PMSGs as applied to wind energy. The second publication addresses the long-term reliability of the proposed LC DD-PMSG design. Publication 3 examines the machine’s electromagnetic design, and Publication 4 introduces an optimization tool developed to quickly define basic machine parameters. The static and harmonic behaviors of the stator and rotor wheel structures are the subject of Publication 5. And finally, Publications 6 and 7 examine steady-state and transient thermal behaviors. There have been a number of ancillary concrete outcomes associated with the work including the following. X Intellectual Property (IP) for direct liquid cooling of stator windings via an embedded coaxial coolant conduit, IP for a lightweight wheel structure for lowspeed, high-torque electrical machinery, and IP for numerous other details of the LC DD-PMSG design X Analytical demonstrations of the equivalent reliability of the LC DD-PMSG; validated electromagnetic, thermal, structural, and dynamic prediction models; and an analytical demonstration of the superior partial load efficiency and annual energy output of an LC DD-PMSG design X A set of LC DD-PMSG design guidelines and an analytical tool to establish optimal geometries quickly and early on X Proposed 8 MW LC DD-PMSG concepts for both inner and outer rotor configurations Furthermore, three technologies introduced could be relevant across a broader spectrum of applications. 1) The cost optimization methodology developed as part of this work could be further improved to produce a simple tool to establish base geometries for various electromagnetic machine types. 2) The layered sheet-steel element construction technology used for the LC DD-PMSG stator and rotor wheel structures has potential for a wide range of applications. And finally, 3) the direct liquid-cooling technology could be beneficial in higher speed electromotive applications such as vehicular electric drives.

Work and non-work : on work and meaning

I den politiska retoriken florerar debattinlägg om arbetslivet, och målsättningen är för det mesta att så många som möjligt ska arbeta så länge som möjligt. Att skapa jobb och minimera arbetslösheten ses som de främsta utmaningarna. På ett individuellt plan beskrivs arbete ofta som personligt självförverkligande eller som en nödvändig form av inkomst som kräver att livet struktureras enligt behovet av sysselsättning. I avhandlingen diskuteras hur de här till synes självklara rollerna som arbete spelar kan sägas neutralisera arbete. Med detta menas att kontroverser kring arbetets mening åsidosätts så att politiskt och etiskt grundläggande frågor om ett gott liv och mänskliga gemenskaper inte ges plats. Genom att gå i dialog med kritiska tänkare som Hannah Arendt, André Gorz, Kathi Weeks, Karl Marx och Richard Sennett diskuteras riskerna med att behandla arbete som en resurs, ett gemensamt samhällsprojekt eller individuellt självförverkligande. Vad är nödvändigt arbete? Vad innebär det att arbete är en vara? Vad är problemet med fragmentering av arbete? Det sägs ofta att arbete har blivit alltmer gränslöst – är detta något positivt eller negativt? Utifrån sådana frågor tar avhandlingen fasta på spänningar i arbetets roll i våra liv och i samhället. Genom att artikulera spänningar utmanas en neutralisering av arbetets etiskt och politiskt brännbara dimensioner. Avhandlingen syftar därmed till att lyfta fram ständigt pågående sätt att ifrågasätta och reflektera kring arbetets mening.

How computer programmers work : understanding software development in practise

Hur arbetar en framgångsrik programmerare? Uppgifterna att programmera datorspel och att programmera industriella, säkerhetskritiska system verkar tämligen olika. Genom en noggrann empirisk undersökning jämför och kontrasterar avhandlingen dessa två former av programmering och visar att programmering innefattar mer än teknisk förmåga. Med utgångspunkt i hermeneutisk och retorisk teori och med hjälp av både kulturvetenskap och datavetenskap visar avhandlingen att programmerarnas tradition och värderingar är grundläggande för deras arbete, och att båda sorter av programmering kan uppfattas och analyseras genom klassisk texttolkningstradition. Dessutom kan datorprogram betraktas och analyseras med hjälp av klassiska teorier om talproduktion i praktiken - program ses då i detta sammanhang som ett slags yttranden. Allt som allt förespråkar avhandlingen en återkomst till vetenskapens grunder, vilka innebär en ständig och oupphörlig cyklisk rörelse mellan att erfara och att förstå. Detta står i kontrast till en reduktionistisk syn på vetenskapen, som skiljer skarpt mellan subjektivt och objektivt, och på så sätt utgår från möjligheten att uppnå fullständigt vetande. Ofullständigt vetande är tolkandets och hermeneutikens domän. Syftet med avhandlingen är att med hjälp av exempel demonstrera programmeringens kulturella, hermeneutiska och retoriska natur.

Thoughts on work-in-progress crowdsourcing metrics of digital collections

The presentation consists of work-in-progress metrics of #digitalkoot, the crowdsourcing project launched by National Library of Finland

Designing gamification for collaborative learning in group work

Computer Supported Collaborative Learning (CSCL) is a teaching and learning approach which is widely adopted. However there are still some problems can be found when CSCL takes place. Studies show that using game-like mechanics can increase motivation, engagement, as well as modelling behaviors of players. Gamification is a rapid growing trend by applying the same mechanics. It refers to use game design elements in non-game contexts. This thesis is about combining gamification concept and computer supported collaborative learning together in software engineering education field. And finally a gamified prototype system is designed.

TYÖILMOITUS TYÖNANTAJALUPAUKSIEN JA TYÖARVOJEN VIESTIJÄNÄ Tarkastelussa menestyneitä Great Place to Work -työnantajia

Työilmoitus voi jäädä työnhakijan ja työnantajan välillä ainoaksi viestinnän mahdollisuudeksi, jolloin ratkaisevaa on, kuinka houkuttelevaksi työnantaja työilmoituksensa laatii kilpaillessaan halutuista osaajista. Samalla työilmoitus antaa lupauksia tulevasta työstä ja työyhteisöstä. Tämän tutkimuksen perimmäinen tarkoitus on tutkia, näkyykö työsuhteen kahdenvälinen transaktioluonne työilmoitusten tasolla eli kerrotaanko ilmoituksissa työnantajan osaajatarpeiden lisäksi, mitkä olisivat työntekijän työllistymisellä saavutetut hyödyt. Tarkemmiksi tarkastelun kohteiksi on valittu kaksi työnhakijan päätöksenteon kannalta mielenkiintoista näkökulmaa: viestityt työarvot ja työnantajalupaukset. Teoreettiselta taustaltaan tämä tutkimus liittyy rekrytoinnin kokonaisuuteen, mutta se sivuaa useita muita aihealueita, kuten yksilön ja yrityksen yhteensopivuutta, työnantajamielikuvaa, psykologista sopimusta, informaation prosessointia, suostuttelua ja työnhakupäätöksen syntymekanismin tutkimusta. Tutkimuksen empiirinen aineisto koostuu kolmena peräkkäisenä vuonna (2013−2015) Suomen parhaimmiksi työnantajiksi tituleerattujen yritysten julkaisemista työilmoituksista. Näiden oletettiin olevan kiinnostuneita työnantajakuvastaan ja rekrytoinnistaan keskimääräistä enemmän. Kerätyistä 19 työilmoituksesta tulkittiin arvoilmaisuja ja annettuja esilupauksia kahden teoreettisen luokituksen yhdistelmänä muodostetun analyysirungon avulla. Aineiston lauseita eriteltiin analyysirungon teemojen alle ja niiden vakuuttamiskeinoja analysoitiin retorisella diskurssianalyysillä. Tutkimuksen tuloksena havaittiin, että työnteon puitteista, palkkatiedoista, määräysvallasta ja työn merkityksellisyydestä mainittiin verrattain vähän työilmoituksissa. Sen sijaan aineiston työilmoituksista löytyi runsaasti ilmaisuja, joista työnhakija voi tehdä päätelmiä työilmapiiristä tai potentiaalisten kollegoiden asiantuntijuuden tasosta. Yrittäjähenkisyys- ja suorituspainepuheiden läpi heijastui puolestaan kovemmat arvot. Arvojen ilmaisu tapahtui usein epäsuorasti kuin selkeinä arvolistoina. Konkreettisia lupauksia työnantajalta työnhakijalle tehtiin vähän tai ne olivat ylimalkaisia. Tutkimus antaa aihetta laajemmille kartoituksille. Mitkä ovat syyt tiettyä kaavaa toistavien työilmoitusten taustalla ja mitkä tekijät työilmoituksissa eri kohdeyleisöjä aidosti vaikuttavat?

Economic capital allocation

For my Licentiate thesis, I conducted research on risk measures. Continuing with this research, I now focus on capital allocation. In the proportional capital allocation principle, the choice of risk measure plays a very important part. In the chapters Introduction and Basic concepts, we introduce three definitions of economic capital, discuss the purpose of capital allocation, give different viewpoints of capital allocation and present an overview of relevant literature. Risk measures are defined and the concept of coherent risk measure is introduced. Examples of important risk measures are given, e. g., Value at Risk (VaR), Tail Value at Risk (TVaR). We also discuss the implications of dependence and review some important distributions. In the following chapter on Capital allocation we introduce different principles for allocating capital. We prefer to work with the proportional allocation method. In the following chapter, Capital allocation based on tails, we focus on insurance business lines with heavy-tailed loss distribution. To emphasize capital allocation based on tails, we define the following risk measures: Conditional Expectation, Upper Tail Covariance and Tail Covariance Premium Adjusted (TCPA). In the final chapter, called Illustrative case study, we simulate two sets of data with five insurance business lines using Normal copulas and Cauchy copulas. The proportional capital allocation is calculated using TCPA as risk measure. It is compared with the result when VaR is used as risk measure and with covariance capital allocation. In this thesis, it is emphasized that no single allocation principle is perfect for all purposes. When focusing on the tail of losses, the allocation based on TCPA is a good one, since TCPA in a sense includes features of TVaR and Tail covariance.

Ethical leadership as a way to promote work-related well-being

The purpose of this study was to clarify the connections of ethical leadership with the work-related well-being of employees. Additionally, the role of occupational health care in ethical leadership that promotes work-related well- being was analyzed. The objective of the study was to produce knowledge to support the development of ethical leadership and work-related well-being as well as to find ways for occupational health care to support organizations in these actions. The target groups of this study consisted of the managers (N=43) and employees (N=336) working in one organization in the Finnish energy industry. The population was studied in November 2014 using census. The data was gathered with two different web-based surveys containing structured and open questions. The survey for managers consisted of background questions and statements concerning ethical leadership, work-related well-being and occupational health care. The employee questionnaire consisted of questions about background and statements about work-related well-being and ethical leadership. The structured questions were analyzed with SPSS Statistical Program and the open questions using inductive content analysis. At least 80 % of the managers saw their actions as ethical in all but one part of ethical leadership. The work-related well-being of the employees was found best in the area of ability to work (91 % agreed) and lowest in the area of experience of ethical leadership (67 % agreed). The results showed a strong positive connection between ethical leadership and all the components of work- related well-being. The managers and employees were generally quite happy with the services of occupational health care but managers saw some problems with the collaboration with occupational health care. Several ways to improve work-related well-being and collaboration with occupational health care were found. One of the most important things was thought to be offering ways to maintain ability to work and making these actions visible. Investing in ethical leadership and work-related well-being is extremely important for the success of an organization and the societal benefits cannot be forgotten either. The role of occupational health care in promoting the health and well-being of employees is substantial. Occupational health care should offer managers more tools to recognize difficult situations and acting in them as well as encourage managers to seek help from occupational health care without hesitation in problematic situations of leadership.

The functional fit between collaborative software and work systems:Qualification of work system needs to software functionality

The study develops an approach that tries to validate software functionality to work systems needs in SMEs. The formulated approach is constructed by using a SAAS based software i.e., work collaboration service (WCS), and SMEs as the elements of study. Where the WCS’s functionality is qualified to the collaboration needs that exist in operational and project work within SMEs. For this research constructivist approach and case study method is selected because the nature of the current study requires an in depth study of the work collaboration service as well as a detailed study of the work systems within different enterprises. Four different companies are selected in which fourteen interviews are conducted to gather data pertaining. The work systems method and framework are used as a central part of the approach to collect, analyze and interpret the enterprises work systems model and the underlying collaboration needs on operational and project work. On the other hand, the functional model of the WCS and its functionality is determined from functional model analysis, software testing, documentation and meetings with the service vendor. The enterprise work system model and the WCS model are compared to reveal how work progression differs between the two and make visible unaddressed stages of work progression. The WCS functionality is compared to work systems collaboration needs to ascertain if the service will suffice the needs of the project and operational work under study. The unaddressed needs provide opportunities to improve the functionality of the service for better conformity to the needs of enterprise and work. The results revealed that the functional models actually differed in how operational and project work progressed within the stages. WCS shared similar stages of work progression apart from the stages of identification and acceptance, and progress and completion stages were only partially addressed. Conclusion is that the identified unaddressed needs such as, single point of reference, SLA and OLA inclusion etc., should be implemented or improved within the WCS at appropriate stages of work to gain better compliance of the service to the needs of the enterprise an work itself. The developed approach can hence be used to carry out similar analysis for the conformance of pre-built software functionality to work system needs with SMEs.

Ethical leadership as a way to promote work-related well-being

The purpose of this study was to clarify the connections of ethical leadership with the work-related well-being of employees. Additionally, the role of occupational health care in ethical leadership that promotes work-related well- being was analyzed. The objective of the study was to produce knowledge to support the development of ethical leadership and work-related well-being as well as to find ways for occupational health care to support organizations in these actions. The target groups of this study consisted of the managers (N=43) and employees (N=336) working in one organization in the Finnish energy industry. The population was studied in November 2014 using census. The data was gathered with two different web-based surveys containing structured and open questions. The survey for managers consisted of background questions and statements concerning ethical leadership, work-related well-being and occupational health care. The employee questionnaire consisted of questions about background and statements about work-related well-being and ethical leadership. The structured questions were analyzed with SPSS Statistical Program and the open questions using inductive content analysis. At least 80 % of the managers saw their actions as ethical in all but one part of ethical leadership. The work-related well-being of the employees was found best in the area of ability to work (91 % agreed) and lowest in the area of experience of ethical leadership (67 % agreed). The results showed a strong positive connection between ethical leadership and all the components of work- related well-being. The managers and employees were generally quite happy with the services of occupational health care but managers saw some problems with the collaboration with occupational health care. Several ways to improve work-related well-being and collaboration with occupational health care were found. One of the most important things was thought to be offering ways to maintain ability to work and making these actions visible. Investing in ethical leadership and work-related well-being is extremely important for the success of an organization and the societal benefits cannot be forgotten either. The role of occupational health care in promoting the health and well-being of employees is substantial. Occupational health care should offer managers more tools to recognize difficult situations and acting in them as well as encourage managers to seek help from occupational health care without hesitation in problematic situations of leadership.