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In this thesis, the basics of electromagnetic theory for wave-energy conversion are reviewed, some of the characteristics of the ocean wave are investigated, some of the power take-off (PTO) systems are introduced, and details about linear permanent magnetic machines, in particular, are discussed.  The thesis aims to model the novel linear transverse flux machine designed by Anders Hagnestål and to build hysteresis current controller for power factor correc- tion. Although this machine is expected to have high performance in terms of efficiency, it also exhibits a strong mutual interaction between the three phases of the machine. Thus, simplification of the actual model of the machine is im- posed to mitigate the complexity of the machine and facilitate the Simulink model. Four cases of the double band hysteresis control are studied. The cur- rents seem to be responding properly to the control scheme; however, software and hardware programming of a microprocessor would be preferable to ensurethe applicability of the control strategy in a real environment. / I detta examensarbete undersöks elektromagnetisk teori och havsvågors egenskaper. Några energiomvandlingssystem introduceras och permanentmagnetiserade maskiner diskuteras i detalj. Syftet med avhandlingen är att modelleraen ny linjär transversalflödesmaskin som är designad av Anders Hagnestål och att bygga en hysteresbaserad strömkontroll för denna. Även om maskinen förväntas prestera bra, uppvisar den också en stark ömsesidig magnetisk interaktion mellan de tre faserna. För att kunna hantera detta problem och därmed kunna genomföra simuleringar införs en förenklad elektromagnetisk modell av maskinen. En strömkontroller har implementerats i Simulink, där fyra fall av dubbelbandshystereskontroll studerats. Resultaten från simuleringarna visar att strömkontrollern fungerar. Nästa steg i projektet är att utföra mjukvaru och hårdvaruprogrammering av en mikrokontroller för att testa systemet i enverklig miljö.

I en tid kännetecknat av en strävan efter ett mer hållbart samhälle, med utformade långsiktiga klimatmål för förnyelsebara energikällor och minskade utsläpp, arbetar fordonsutvecklare med att ta fram alternativ till förbränningsmotorer. För att nå satta klimatmål och samtidigt förbättra arbetsmiljön med minskat buller anses en elektrisk drivlina som ett troligt alternativ. För tunga fordon såsom lastbilar som ofta utrustas med tillsatsutrustning som kranar, tippbara flak eller cementroterare är beroende av ett kraftuttag för att driva hydraulpumpar och generatorer. Vid en omställning till elektrisk drivlina är det inte längre säkert att möjligheten kvarstår att ta kraft från drivlinan. Detta har lett till en efterfrågan på elektriskt separat drivna kraftuttag uppstått på marknaden. Syftet med denna studie är att undersöka och få en förståelse för inom vilket effektområde och vilken typ av elektrisk motor som är bäst lämpad för att separat driva ett kraftuttag. Målet är att med denna kunskap utveckla en modell som förenklar valet av lämplig elektrisk motor för ett givet fall av kraftuttag. Modellen testas med en effekt på 60 kW vilket resulterade i att en lågvarvig axial flux BLDC-motor anses bäst lämpad. Detta då en lågvarvig elektrisk motor kräver lägre utväxling för att uppfylla krävt vridmoment, vilket ger en lägre totalvikt. Totalvikt för testad effekt hamnar på 78,6 kg, vilket är tre gånger det funktionella kravet. Studien ger en indikation på att det med givna krav enbart är försvarbart att driva kraftuttag med separata elektriska motorer vid låga effekter, runt 10 kW. / In a time characterized by an endeavor for a more sustainable society. With formulated long-term climate targets for renewable energy sources and reduced emissions, vehicle developers are working to develop alternatives to internal combustion engines. In order to achieve set climate targets and at the same time improve the working environment with reduced noise, an electric driveline is considered a likely alternative. For heavy vehicles such as trucks that are often equipped with auxiliary accessories such as cranes, tipper trucks or cement rotators are dependent on a power take-off to drive hydraulic pumps and generators. When switching to an electric driveline, it is no longer certain that the possibility remains to take power from the driveline. This has led to a demand for electrically driven power take-offs on the market. The purpose of this study is to investigate and gain an understanding of the power range and type of electric motor that is best suited to drive a power take-off separately. The goal is to use this knowledge to develop a model that simplifies the choice of a suitable electric motor for a given case of power take-off. The model is tested with an output of 60 kW, which resulted in a low-speed axial flux BLDC-motor being considered best suited. This is because a low-speed electrical motor requires a lower gear ratio to meet the required torque, which gives a lower total weight. The total weight for the tested effect ends up at 78,8 kg, which is three times the functional requirement. The study gives an indication that with given requirements it is only justified to operate power take-offs with separate electric motors at low powers, around 10 kW.

The objective of this thesis is to develop a model that will integrate multiple buoys to a power take-off hub. The model will be derived using a time domain analysis and will consider the hydraulic coupling of the buoys and the power take-off. The derived model is reproduced in MATLAB in order to run simulations. This will give possibility to conduct a parameter study and evaluate the performance of the system. The buoy simulation model is provided by Wave4Power (W4P). It consists of a floater that is rigidly connected to a fully submerged vertical (acceleration) tube open at both ends. The tube contains a piston whose motion relative to the floater-tube system drives a power take-off mechanism. The power take-off model is provided by Ocean Harvesting Technologies AB (OHT). It comprises a mechanical gearbox and a gravity accumulator. The system is utilized to transform the irregular wave energy into a smooth electrical power output. OHT's simulation model needs to be extended with a hydraulic motor at the input shaft. There are control features in both systems, that need to be connected and synchronized with each other. Another major goal within the thesis is to test different online control techniques. A simple control strategy to optimize power capture is called sea-state tuning and it can be achieved by using a mechanical gearbox with several discrete gear ratios or with a variable displacement pump. The gear ratio of the gear box can be regulated according to a 2D look up table based on the average wave amplitude and frequency over a defined time frame. The OHT power take-off utilizes a control strategy, called spill function, to limit the excess power capture and keep the weight accumulator within a span by disengaging the input shaft from the power take-off. This is to be modified to implement power limitation with regulation of the gear ratio of the gearbox. / +46736290781

Wave energy has the potential to provide an energy resource in this challenging energyenvironment. Wave energy converters are devices used to extract this energy and convertit into electricity. Wave Carpet is an example of such a novel wave energy converters andin its final form, it consists of a submerged membrane which covers an arbitrarily largearea above the sea floor. Incident waves create a pressure difference between the upper andlower surfaces, which triggers an up-and-down movement. The power take-off attached tothe surfaces serve to restrict this movement and thereby extract hydraulic power which isconverted to electricity.The Wave Carpet, is a type of wave energy converter that is beingdeveloped at University of California Berkeley′s Theoretical and Applied Fluid DynamicsLaboratory (TAFLab).The thesis aims at modeling and designing the different power conversion chainof the entire wave energy converter device. The process of energy conversion that yieldsthe required electrical energy for connecting a wave energy converter to an electricalnetwork is termed as the power conversion chain. A detailed electro-mechanical modelof the wave energy converter system connected to power grid is developed in theMatlab/SIMULINK environment and its corresponding generator and hydraulic controlstructure is implemented. The simulation response of the wave energy converter alongwith the power conversion chain is investigated. / Vågenergi har potential att bli en energiresurs i en utmanande energimiljö. Vågkraftverkär maskiner som används till att utvinna denna energi och omvandla den till elektricitet.Wave Carpet är ett exempel på ett vågkraftverk som i sitt slutglitiga stadie bestårav ett nedsänkt membran som täcker ett godtyckligt stort område ovanför sjöbotten.Inkommande vågor skapar en tryckskillnad mellan den övre och nedre ytan som gerupphov till en lodrätt rörelse. De mekaniska armarna kopplade till membranet bromsardenna rörelse och kan genom hydraulik omvandla bromsenergin till elektricitet. The WaveCarpet är en typ av vågkraftverk som utvecklas vid University of California Berkeley′sTheoretical and Applied Fluid Dynamics Laboratory (TAFLab).Uppsatsen syftar till att modellera och designa effektomvandlingskedjan i ett sådantvågkraftverk. Energiomvandlings processen som ger upphov till elektriciteten via ettvågkraftverk är benämnt som effektomvandlingskedjan. En detaljerad elektro-mekaniskmodell över ett vågkraftverksystem kopplat till ett elnät med motsvarande generator ochhydraliska regulatorer är utvecklad i Matlab/Simulink miljön. Simuleringsresultaten fråndet modellerade vågkraftverket undersöks tillsammans med effektomvandlingskedjan.

<div> This thesis proposes an artificial neural network (NN) model to predict fuel consumption in heavy vehicles. The model uses predictors derived from vehicle speed, mass, and road grade. These variables are readily available from telematics devices that are becoming an integral part of connected vehicles. The model predictors are aggregated over a fixed distance traveled (i.e., window) instead of fixed time interval. It was found that 1km windows is most appropriate for the vocations studied in this thesis. Two vocations were studied, refuse and delivery trucks.</div><div><br></div><div> The proposed NN model was compared to two traditional models. The first is a parametric model similar to one found in the literature. The second is a linear regression model that uses the same features developed for the NN model.</div><div><br></div><div> The confidence level of the models using these three methods were calculated in order to evaluate the models variances. It was found that the NN models produce lower point-wise error. However, the stability of the models are not as high as regression models. In order to improve the variance of the NN models, an ensemble based on the average of 5-fold models was created. </div><div><br></div><div> Finally, the confidence level of each model is analyzed in order to understand how much error is expected from each model. The mean training error was used to correct the ensemble predictions for five K-Fold models. The ensemble K-fold model predictions are more reliable than the single NN and has lower confidence interval than both the parametric and regression models.</div>