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norskArtikler, rapporter og annet (elektroteknologi)
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Quaternion-Based Backstepping Control of Relative Attitude in a Spacecraft Formation
(Journal article; Tidsskriftartikkel, 2006-12)In this paper we present a solution to the problem of controlling relative attitude in a leader-follower spacecraft formation, with focus on the rotation path for the follower spacecraft. Mathematical models of relative attitude kinematics and dynamics are presented, and a nonlinear control law designed by use of integrator backstepping is used to control the relative attitude in the formation. The ... -
A model of relative position and attitude in a leader-follower spacecraft formation
(Chapter; Bokkapittel, 2005)In this paper, a model of a leader-follower spacecraft formation in six degrees of freedom is derived and presented. The nonlinear model describes the relative translational and rotational motion of the spacecraft, and extends previous work by providing a more complete factorization, together with detailed information about the matrices in the model. In addition, mathematical models of orbital ... -
Addressing Cross-Coupling Issues in Magnetically Integrated Three-Port DC-DC Converters
(Conference object; Konferansebidrag, 2024-10-25)DC grid-forming converters are used to provide dc power distribution inside buildings. Often, such converters are based on dual-active bridge (DAB) technology to provide high-frequency isolation. Certain developing standards related to dc installations specify different isolation classes and protection zones. This is a critical requirement for power converter design, especially for building applications ... -
Single-Stage, Single-Phase Current Source Inverter for Standalone Applications
(Chapter; Bokkapittel, 2024-03-10)The current source inverters (CSI) are considered more reliable than their voltage source counterparts due to the inherent current-limiting feature. This is particularly interesting for many applications, such as battery energy storage, where there is a possibility of very high short-circuit currents. In addition, CSI can provide an inherent voltage boost capability, allowing integration of extra-low ... -
Vibration and Mobility Analysis of Hovering Rotary Wing UAV for Adaptive FSO Beam Alignment
(Chapter; Bokkapittel, 2024-11-28)Unmanned aerial vehicles (UAVs) are regarded as a potential platform for deploying airborne free space optical (FSO) fronthaul/backhaul links. The challenge emerges from the UAV hovering mobility which deteriorates beam alignment. To solve this challenge, we conducted two hover flights using a quadrotor UAV to measure vibration levels and hover fluctuations offering practical insights into the ... -
An Adaptive Modulation Technique for Power Quality Improvement in Standalone Single-Phase Current Source Inverters
(Chapter; Bokkapittel, 2024-07-15)The presence of low-frequency power oscillations on the DC link and overlap-time both degrade the output power quality of single-phase current source inverters. This paper proposes a novel modulation technique that simultaneously mitigates the effects of both low-frequency power oscillations and overlap-time. By simultaneously addressing these issues, the proposed adaptive modulation technique ... -
Home Energy Management System for a Residential Building in Arctic Climate of Norway Using Non-Intrusive Load Monitoring and Deep Learning
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-05-06)Residential buildings can actively participate in energy management strategies by integrating advanced metering infrastructure to have a reliable and stable distribution system. This paper introduces a novel home energy management system (HEMS) framework to minimize total electricity costs by optimizing the charging of an electric vehicle (EV). The methodology incorporates a non-intrusive load ... -
Fault Tolerant Flight Control for the Traction Phase of Pumping Airborne Wind Energy Systems
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-02)A fault-tolerant control approach is proposed, for a pumping airborne wind energy system (AWES) comprising a tethered fixed-wing aircraft with integrated propellers for vertical take-off and landing (VTOL). First, the flight control design for the traction phase of the system, when the tethered aircraft has to fly in loops using the rudder, is presented. Then, the presence of the propellers, that ... -
Large-Scale Reverse Pumping for Rigid-Wing Airborne Wind Energy Systems
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-25) -
The representation of hydrogen in open-source capacity expansion models
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-12-19)The intermittent nature of wind and solar power has led to a scientific consensus in the international energy research community that a mix of energy sources and carriers is necessary to achieve carbon neutrality. The search for alternatives has sparked renewed interest in Hydrogen (H2) and its derivatives, such as ammonia and methane. It has also motivated researchers to expand their models to study ... -
Experimental Investigation of Free Space Optical Channel Performance in the Arctic Weather
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-11-07)This paper investigates the technical aspects of the 1550 nm free space optical (FSO) link in extreme Arctic weather, specifically in falling snow, which is currently understudied. We measured the time variation of the received optical power in many snowfall events and derived attenuation statistics. Continuous measurements allowed us to estimate attenuation under varying temperatures and humidity ... -
Performance optimization for hybrid TS/PS SWIPT UAV in cooperative NOMA IoT networks
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-29)This study examines a cooperative non-orthogonal multiple access (NOMA) network utilizing an energy-constrained unmanned aerial vehicle (UAV) relay (UAVR) to expand coverage and improve network throughput. In order to provide energy to the UAVR, we consider the hybrid simultaneous wireless information and power transmission (SWIPT) method, which allows the UAVR to harvest energy from the source ... -
Teaching Linear Algebra to Engineering Students in Two Different Educational Settings: Design and Learning Outcomes
(Journal article; Tidsskriftartikkel, 2024-02-16)The present paper holds a twofold perspective on a new teaching format in a linear algebra course given to engineering students. The design resembles the flipped classroom, but with various adjustments. The first part highlights the basis on which the design was built, both research results and practical issues, but also the implementation of the teaching. It did not proceed quite as expected. The ... -
Non-directional Overcurrent Protection Relay Testing Using Virtual Hardware-in-the-Loop Device
(Chapter; Bokkapittel, 2023-05-17)Protective relays are an integral part of the power grid, making it reliable and secure against abnormal conditions. Hardware-in-the-Loop (HIL) can be employed to test and validate digital protective relay devices in the real-time simulation comprising hardware and software before actual implementation. However, the HIL technique requires a complex and high-cost technical environment consisting of ... -
Take-Home Exams in University Mathematics and Science Subjects: Some Ethical Considerations
(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 ... -
Stabilization of Non-Cooperative Satellites in Low Earth Orbits using Inter-Satellite Atmospheric Drag
(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 ... -
Under Seawater Capacitive Power Transfer for Maritime Charging Applications
(Chapter; Bokkapittel, 2023-09-12)Underwater capacitive power transfer (CPT) can provide an inexpensive and light electric charging solution with good misalignment tolerance for unmanned maritime vehicles. This paper investigates the effect of the changing of the frequency and the distance on the power transfer and overall efficiency of the underwater CPT system, considering the dielectric losses of the medium. It also proposes and ... -
Home Load Disaggregation using Deep Learning and Bayesian Optimization: A Case Study in Arctic Climate in Northern Norway
(Chapter; Bokkapittel, 2023-08-03)Load monitoring is an essential task in energy management systems. In this paper, an approach that relies on a long short-term memory (LSTM) model and a discrete wavelet transform (DWT) filter is presented to estimate the energy usage of flexible appliances. In the preprocessing stage, the main features of the aggregated power signal are extracted using DWT. Deep learning methods are very sensitive ... -
Classification of bulk cargo types stored openly at ports using CNN
(Chapter; Bokkapittel, 2023-10-20)In this paper, we present a novel concept of tracking cargoes at open ports using remote sensing images and convolution neural network (CNN) to classify various dry bulk commodities. The dataset used is prepared using Sentinel-2 atmospherically corrected (Sentinel-2 L2A) images covering 12 spectral bands. There are total 4995 labeled and geo-referenced images for four different cargoes-bauxite, coal, ... -
Digital Controller Design and Implementation for AC and DC Side of 3ph qZSI
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-28)This article presents the multi-loop digital controller design of a quasi-z-source inverter (qZSI). The qZSI is a single-stage power converter and can operate in buck and boost modes. The qZSI is an economical solution for distributed generation and eliminates the need for two-stage power conversion. This article proposes a detailed step-wise digital controller design using a multi-loop control ...
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