Now showing items 141-160 of 217

    • Wireless Charging for Small Electric Vessels 

      Omosanya, Hafeez Abolade (Master thesis; Mastergradsoppgave, 2019-06-28)
      With the presence of traditional thick and heavy cables for charging, the risk of humans exposed to high-voltage, and due to mechanical wear and tear in conductive materials, inductive wireless charging was introduced which is the future of charging technology. This project has focused on magnetic-coupled wireless transfer with some key components involved such as a DC voltage source, a full-bridge ...
    • HVDC Transmission and Energy Storage for Wind Power Plant 

      Moe, Torgeir (Master thesis; Mastergradsoppgave, 2019-06-28)
      This thesis will investigate the effects of an energy storage system incorporated into the submodules of a modular multilevel converter connected to a HVDC line. A simulation has been made to see the effects of energy storage on the transmission of power from a generator connected to the grid via a HVDC line with two MMCs connected in each end, one of which incorporates the energy storage system.
    • Design and construction of a half-bridge using wide-bandgap transistors 

      Vatshelle, Fredrik Hausvik (Master thesis; Mastergradsoppgave, 2019-06-28)
      A continuously increasing demand of electric power makes energy efficiency imperative in modern technology. The transistor is considered as the fundamental element of modern electronic products.
    • Sol vinkel estimator. Solpanel rig med dobbel akse orientering 

      Mikkelsen, Rolf Olaf (Master thesis; Mastergradsoppgave, 2019-06-28)
      Denne rapporten presenterer design og simuleringer av en toakset solcellerigg. Denne bestpunktsporingen riggen fungerer utelukkende basert på utgangseffekten til solcellepanelet montert til det. Det bruker ikke noen solsensor til å orientere solcellepanelet. Posisjonen til solen er beregnet basert på tid og stedsinformasjon. Siden dette solpanelet vil bli montert her på UiT, Norges Arktiske Universitet, ...
    • Energy storage technologies from a power system point of view 

      Wang, Raymond Klippenvåg (Master thesis; Mastergradsoppgave, 2019-06-28)
      This thesis presents energy storage technologies, as well as their most applicable ways of integration into the power system. The storage technologies provided are relevant in regards to ancillary services, peak shaving, energy arbitrage and not least integration in combination with intermittent renewable production. A grid analysis was performed to determine the obvious differences between different ...
    • Themes within lecturers' views on the teaching of linear algebra 

      Rensaa, Ragnhild Johanne; Hogstad, Ninni Marie; Monaghan, John David (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-25)
      This paper reports on themes that arose in an investigation of university lecturers’ views on the teaching of linear algebra. This focus on themes was the initial part of a study concentrating on four areas: What is important to teach in a first course in linear algebra? Are there teaching methods which are particularly suited for such a course? Are there tools that should/should not be used; and ...
    • Swedish first-year engineering students’ views of mathematics, self-efficacy and motivation and their effect on task performance 

      Tossavainen, Timo; Rensaa, Ragnhild Johanne; Johansson, Monica (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-29)
      We examine a group (N = 88) of Swedish first-year engineering students, their motivation, self-efficacy, and beliefs about the nature of mathematics, and how these relate to their task performance in mathematics. In our data, engineering students who emphasized the exact reasoning in their view of mathematics performed significantly better in a set of mathematical tasks than those who emphasized ...
    • Dual quaternion control: a review of recent results within motion control 

      Johansen, Tor-Aleksander; Sánchez, José J.; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-24)
      This paper presents a review of recent results in the field of dual quaternion based motion control. In addition, we derive two control laws for trajectory tracking control of a fully actuated rigid-body based on the resemblance of dual quaternion kinematics and dynamics to the quaternion based rotational kinematics and dynamics. A velocity error sliding surface and an integrator backstepping ...
    • Preliminary Results on Waypoint Tracking for Spacecraft with Actuator Constraints 

      Oland, Espen; Andersen, Tom Stian (Peer reviewed; Chapter; Bokkapittel, 2019-07-22)
      This paper presents preliminary results on how to perform waypoint tracking with spacecraft with actuator constraints. It considers a simplified spacecraft model and can be considered a deep space model, and shows how to perform waypoint tracking with only one main thruster together with full attitude control. As the spacecraft reaches close to the waypoint during a deceleration phase that makes the ...
    • Controlling a Chain of Integrators with Constrained Actuation Using Exponential Activation Functions 

      Oland, Espen; Kristiansen, Raymond (Peer reviewed; Chapter; Bokkapittel, 2019-10-24)
      This paper shows how to control a chain of integrators with constrained actuation by using exponential activation functions. Specifically, it shows how the control law can be decomposed into several parts that can be activated as they are required, resulting in a simple control law that is able to make the states converge fast to zero.
    • Ant colony optimization and analysis of time step resolution in transmission expansion computations for wind power integration 

      Fuchs, Ida; Gjengedal, Terje (Chapter; Bokkapittel, 2011)
      This paper investigates the necessary time step resolution in a transmission expansion planning algorithm based on ant colony optimization. A maximal and efficient wind power integration is the main motivation for the grid expansion, which requires a planning tool dealing with wind energy fluctuations. For the analysis a power system model for the Nordic area is used, including a wind power ...
    • PD+ based trajectory tracking of the underactuated quadrotor platform using dual quaternions 

      Johansen, Tor-Aleksander; Andersen, Tom Stian; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-29)
      We address the problem of state feedback trajectory tracking of the underactuated quadrotor platform in the dual quaternion framework through a PD+ tracking controller. The control law negates the need of generating a desired attitude trajectory as the translational error is mapped directly onto the rotational actuators through a virtual frame. More precisely, we show uniform practical asymptotic ...
    • Interpreting teaching for conceptual and for procedural knowledge in a teaching video about linear algebra 

      Rensaa, Ragnhild Johanne; Vos, Pauline (Journal article; Tidsskriftartikkel, 2018)
      The aim of this study is to investigate teaching videos about mathematics, seeking to uncover research-based foundations for their quality. By drawing on the notions of procedural and conceptual knowledge, the research was operationalized by asking professionals in undergraduate mathematics education (n=18) to interpret sections of a teaching video. The video dealt with a topic in linear algebra. ...
    • Evaluation of cascaded MPC performance in voltage source converters 

      Mokrushev, Ivan (Master thesis; Mastergradsoppgave, 2018-08-21)
      Model predictive control method becomes more popular in research over the last decade. Due to the growing popularity of the model predictive control concept, there are more and more questions about the effectiveness of this method in comparison with other methods. In this thesis cascaded model predictive control of grid connected voltage source converter with LCL filter has been evaluated. The ...
    • Transient analysis of road tunnel power system 

      Ivanova, Elizaveta (Master thesis; Mastergradsoppgave, 2018-08-16)
      The main tasks of Statens Vegvesen is to plan, build and maintain the roads of Norway. Tunnels are included as a part of this task. Due to expected changes in usage patterns and needs, the Norwegian authorities decided to adapt to the European model the design of low voltage networks. The backup power system is one of the most important parts of the installation and presents an independent source ...
    • Charging technology for small maritime vessels 

      Hoff, Bjarte (Conference object, 2019-01-21)
    • Engineering students' instrumental approaches to mathematics; some positive characteristics 

      Rensaa, Ragnhild Johanne (Journal article; Peer reviewed, 2018)
      The present paper presents three deliberately chosen mathematical episodes observed in a class of engineering students taking a basic calculus course. By drawing on analyses of instrumental and relational learning strategies, the episodes are shown to illustrate instrumental approaches indicated by the students. The paper discusses positive characteristics about these approaches while further data ...
    • Framework for Modeling and Simulation of Household Appliances 

      Bjerknes Nilsen, Christian; Hoff, Bjarte; Østrem, Trond (Peer reviewed; Chapter, 2018-12-31)
      This paper describes a framework for simulating household appliances in Simulink. Typical Norwegian household equipment have been analyzed based on their characteristic behavior, to establish the requirement for synthesizing and recreating their current waveform, harmonic currents and phase shift. Both detailed simulation of the current waveform and RMS currents for simulation over longer time periods ...
    • Modeling and Attitude Control of Satellites in Elliptical Orbits 

      Oland, Espen (Peer reviewed; Chapter, 2018-11-05)
      The attitude determination and control system (ADCS) for spacecraft is responsible for determining its orientation using sensor measurements and then applying actuation forces to change the orientation. This chapter details the different components required for a complete attitude determination and control system for satellites moving in elliptical orbits. Specifically, the chapter details the orbital ...
    • A Comparative Study of Different Control Structures for Flight Control with New Results 

      Oland, Espen; Kristiansen, Raymond; Gravdahl, Jan Tommy (Peer reviewed; Book; Chapter, 2018-10-24)
      This paper presents several different control structures that facilitate flight control and does a comparison between them. Specifically, this paper considers command-filtered backstepping, nonlinear dynamic inversion (NDI), and a new decoupled approach that decouples the rotational and translational dynamics by estimating the higher order derivatives of the angle of attack and sideslip angle. The ...