• Reactive-Based Position Control of an Underactuated Quadrotor 

      Andersen, Tom Stian; Kristiansen, Raymond (Chapter; Bokkapittel, 2020-07-20)
      This paper addresses the problem of position control or waypoint tracking for an underactuated quadrotor. The proposed control law is what is known as reaction based in the way that the attitude system reacts to errors in the translational motion. This methodology requires no generation of desired attitude or angular velocity and the resulting control law is model-independent in that it does ...
    • Real-Time Implementation of Two Grid-Forming Power Converter Controls to Emulate Synchronous Generators 

      Azuara-Grande, Luis Santiago; Gonzalez-Longatt, Francisco; Tricarico, Gioacchino; Wagle, Raju; Arnaltes, Santiago; Granizo, Ricardo (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-09)
      Modern power systems are experiencing unprecedented penetration of integrating renewable energy sources (RES) to tackle the so-called climate emergency. But the transition from synchronous generators to converter-interfaced generators also produces a few issues, some of them directly related to the reduction (or lack) of rotational inertia. The voltage source converters (VSCs) enabled with the ...
    • Real-Time Particle Tracking using a Formation of UAVs 

      Oland, Espen; Kristiansen, Raymond (Journal article; Peer reviewed; Tidsskriftartikkel, 2013)
      In this paper the problem of real-time particle tracking is studied. Using sensor measurements, a formation of UAVs autonomously find the closest point with high particle density where they enter a holding pattern. After converging to the holding pattern, one UAV will remain, while the rest will go looking for other maxima. To avoid collisions between the UAVs during the mission, a controller is ...
    • Real-Time Price-Based Optimal Energy Mix in Smart Distribution Network 

      Wagle, Raju; Sharma, Pawan; Charu, Sharma; Amin, Mohammad (Chapter; Bokkapittel, 2023-04-29)
      With the increasing penetration of Distributed Energy Resources (DERs) in Smart Distribution Networks (SDNs), balancing energy mix is a crucial task for distribution system operators. The aggregate consumption, generation, and power exchanged from the upstream network are essential for the energy management system. Appropriate allocation and scheduling of DERs and Energy Storage can minimize the ...
    • Real-time Volt-Var control of grid forming converters in DER-enriched distribution network 

      Wagle, Raju; Sharma, Pawan; Charu, Sharma; Amin, Mohammad; Gonzalez-Longatt, Francisco (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-06)
      The growing installation of distributed energy resources (DERs) in a distribution network (DN) poses substantial issues related to voltage regulation. Due to constrained switching operation and slower response time, traditional voltage regulation devices cannot handle current voltage-related challenges. One alternative to solve these problems is to use smart converters to control the reactive ...
    • A Reliable Modular Based PV-Battery Hybrid System with Peak Shaving Capability 

      Sohail, Umer; Nademi, Hamed; Norum, Lars Einar (Peer reviewed; Chapter, 2018)
      The driving factors in emerging photovoltaic (PV) systems and battery-energy-storage systems (BESS) are highly scalable feature, modular and flexible structures with superior transformerless performance. The feasibility of Modular Multilevel Converter (MMC) to operate without overall DC-link allows the integration of PV generators and battery strings with its submodules (SMs), whereas each SM acts ...
    • A Review of Power Converters for Ships Electrification 

      Al-Sallami, Hussein Mahdi Yaseen; Hoff, Bjarte; Østrem, Trond (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-07)
      Fully electric ships have become popular to meet the demand for emission-free transportation and improve ships' functionality, reliability, and efficiency. Previous studies reviewed the shipboard power systems, the different types of shipboard energy storage devices, and the influences of the shore-to-ship connection on ports' electrical grid. However, the converter topologies used in the electrification ...
    • Roach Infestation Optimization MPPT Algorithm for Solar Photovoltaic System 

      Calay, Rajnish K; Pradhan, Chittaranjan; Senapati, Manoj Kumar; Ntiakoh, Nicholas Kakra (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-16)
      Solar photovoltaic (PV) power has several advantages such as free availability, absence of rotating parts, can be easily integrated with building architecture, and need little maintenance. However, the PV cell current–voltage (I–V) characteristics are non-linear and power generated from a PV array depends on solar insolation/irradiation and panel temperature. The extracted PV output power is ...
    • Secondary Network Throughput Optimization of NOMA Cognitive Radio Networks Under Power and Secure Constraints 

      Vo, Van Nhan; Viet Hung, Dang; Tran, Hung; Ha, Dac-Binh; Le, Cong; Ho, Tu Dac; Chakchai, So-In (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-31)
      Recently, the combination of cognitive radio networks with the nonorthogonal multiple access (NOMA) approach has emerged as a viable option for not only improving spectrum usage but also supporting large numbers of wireless communication connections. However, cognitive NOMA networks are unstable and vulnerable because multiple devices operate on the same frequency band. To overcome this drawback, ...
    • Security Constrained Unit Commitment and Economic Dispatch applied to the Modified IEEE 39-bus system Case 

      Tricarico, Gioacchino; Azuara-Grande, Luis Santiago; Wagle, Raju; Gonzalez-Longatt, Francisco; Dicorato, Maria; Forte, Giuseppe; Rueda, Jose Luis (Journal article; Tidsskriftartikkel, 2022-12-09)
      The operation schedule of the power generation units in electrical power systems is determined by the optimisation problem known as unit commitment (UC), aiming at minimising the total cost considering the generation constraints. To obtain a feasible solution from the network perspective, the security-constrained UC (SCUC) problem has been defined to embed the network constraints in the optimisation ...
    • Security Constrained Unit Commitment and Economic Dispatch by AC Sensitivity Factors 

      Tricarico, Gioacchino; Wagle, Raju; Azuara-Grande, Luis Santiago; Gonzalez-Longatt, Francisco; Dicorato, Maria; Forte, Giuseppe; Rueda, Jose Luis (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-09)
      The dispatch schedule of the electrical power plant units is the result of the solution to the unit commitment optimisation problem, and it minimises the cost of production considering pre-defined technical limits. The security-constrained unit commitment problem has been defined as including the network constraints in the previously mentioned optimisation problem to obtain a feasible power system ...
    • Smart grid solutions for integration of renewable energy in remote communities 

      Hoff, Bjarte (Conference object; Konferansebidrag, 2017)
    • Smarte løsninger for integrering av fornybar energi 

      Hoff, Bjarte (Konferansebidrag; Conference object, 2017)
    • Smarte nett - Framtidas fleksible energisystem 

      Hoff, Bjarte (Conference object; Konferansebidrag, 2016)
    • Smarte nett - Framtidas fleksible energisystem 

      Hoff, Bjarte (Konferansebidrag; Conference object, 2016-03-16)
    • Stabilization of Non-Cooperative Satellites in Low Earth Orbits using Inter-Satellite Atmospheric Drag 

      Oland, Espen; Kristiansen, Raymond (Chapter; Bokkapittel, 2023-08-07)
      This paper presents a novel solution to the problem of stabilization of non-cooperative satellites in low Earth orbits, which utilizes inter-satellite aerodynamic drag effects for generation of aerodynamics moments in the wake of a controlled satellite. Hence, by altering the position of a smaller controlled satellite, we are able to change the wake region and thus provide aerodynamic moments for ...
    • Subsumption architecture applied to flight control using composite rotations 

      Oland, Espen; Andersen, Tom Stian; Kristiansen, Raymond (Peer reviewed; Tidsskriftartikkel; Journal article, 2016-03-19)
      In this paper the subsumption theory is applied to flight control through composite rotations where multiple tasks can be defined as simple rotations. The tasks can then be arranged as a hierarchy, where the primary task is always fully pursued, and conflicting lower level tasks are removed by the primary rotation. The concept is applied to a group of uavs that move through an urban terrain while ...
    • 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 ...
    • Take-Home Exams in University Mathematics and Science Subjects: Some Ethical Considerations 

      Rensaa, Ragnhild Johanne; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2024)
      This article addresses some challenging perspectives related to offering take-home exams in mathematics at university level. The challenges arose during work on a previous article where four perspectives originating from Bjerrum Nielsen’s framework (2003) were used to analyze universities’ assessment methods during the Covid lockdown in our country. The perspectives had some ethical considerations ...
    • 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 ...