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norskInstitutt for elektroteknologi: Nye registreringer
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Modified demagnetisation control strategy for low-voltage ride-through enhancement in DFIG-based wind systems
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-16)The large-scale wind energy conversion systems (WECSs) based on doubly-fed induction generators (DFIGs) are very popular in recent years due to the numerous technical and economic benefits. With the increasing penetration level of wind energy, the latest grid codes require the DFIG-based WECSs to remain connected to the grid under grid fault scenarios and deliver the required reactive power into ... -
Optimal Volt Var control in Smart Distribution Networks
(Master thesis; Mastergradsoppgave, 2021-05-24)Both the generation and transmission power networks are facing new threats and opportunities as the number of distributed energy resources (DERs) grows. Because of the high solar PV penetration, voltage rise and voltage volatility are becoming major problems in the distribution network. Voltage regulating devices (VRDs), such as on load tap changers (OLTCs), phase voltage regulators (SVRs), and ... -
Designing an Autonomous Racing Drone
(Master thesis; Mastergradsoppgave, 2021-05-19)In recent years drone racing using human pilots have increased in popularity. This combined with the increased usage of autonomous driving vehicles have sparked a new field of interest which is Autonomous Racing Drones competitions. This thesis explores the field of drone design and avionics with the conclusion of presenting the first Racing Drone prototype that can be used in future work made by ... -
Continuous Autonomous UAV Inspection for FPSO vessels
(Master thesis; Mastergradsoppgave, 2021-06-23)This Master's thesis represents the preliminary design study and proposes the unmanned aerial vehicle (UAV) -based inspection framework, comprising several multirotors with automatic charging and deployment for 24/7 integrity inspection tasks. This project has three main topics. First one describes the operational environment and existing regulations that cover use of UAVs. It forms the basis ... -
Optimal bruk av reaktive ressurser
(Master thesis; Mastergradsoppgave, 2021-05-18)God kontroll av reaktiv effekt er en helt nødvendig del av et velfungerende kraftsystem. Reaktiv effekt er funksjon av spenning og lastvinkel, men er i størst grad påvirket av spenningen under normale forhold. Det finnes mange forskjellige reaktive ressurser i kraftsystemet, og de har forskjellige egenskaper og karakteristikker. Statiske reaktive ressurser er kondensatorbatterier, reaktorer og ... -
Roach Infestation Optimization MPPT Algorithm of PV Systems for Adaptive to Fast-Changing Irradiation and Partial Shading Conditions
(Master thesis; Mastergradsoppgave, 2021-05-18)Of all the renewable energy sources, solar photovoltaic (PV) power is considered to be a popular source owing to several advantages such as its free availability, absence of rotating parts, integration to building such as roof tops and less maintenance cost. The nonlinear current–voltage (I–V) characteristics and power generated from a PV array primarily depends on solar insolation/irradiation and ... -
Study & Analysis of Power Switches with reverse voltage blocking capability
(Master thesis; Mastergradsoppgave, 2021-05-25)This thesis hovers over the basic introduction to Silicon Carbide (Metal Oxide Semiconductors Field-effect Transistor) MOSFET switches and the circuit designing of Current Source Invertors using SiC MOSFET switches. The thesis covers the basic grounds for all the steps needed in the implementation of hardware design for half bridge, full bridge and three phase CSIs in the future. Firstly, a ... -
Wireless charging of offshore wind service vessels
(Master thesis; Mastergradsoppgave, 2021-05-18)This report discusses the possibility for wireless charging solutions for electric vessels, with a focus on offshore wind turbine service. Where the charging time is minimal and safety for crew is important. Different types of wireless technologies have been studied, where the Inductive power transfer (IPT) is shown to be the preferred technology. Inductive power transfer (IPT) grants a safe ... -
Modeling and Analyzing of Inverters for Controlling Voltage and Frequency in an Islanded Microgrid
(Master thesis; Mastergradsoppgave, 2021-05-18)Recently, the growth of inverter-based generations (IBGs) like solar photovoltaic (PV) and wind turbine generators in the form of microgrids (MGs) has been increasing. However, control of voltage and frequency becomes a challenging task for MGs especially when they operate in an islanded mode, due to the inherent low-inertia feature of IBGs compared to a grid-tied mode where there is a grid support. ... -
Tethered Quadcopter Control, Simulation and Modeling platform for a small USV
(Master thesis; Mastergradsoppgave, 2021-05-18)Maritime Robotics main intent of the thesis is to develop understanding of a small deployable camera platform capable of providing elevated situational awareness for a small USV using a tether. The thesis goes into the state-ofthe-art methods of usage and control of a tethered drone. The thesis goes into the building and operating of the QAV250 Pixhawk 4 mini drone and making a drone simulation ... -
Study of Inter Area Oscillations Using Phasor Measurement Units
(Master thesis; Mastergradsoppgave, 2021-05-18)Low-frequency oscillations in the power system have major repercussions on power system stability and the objective of maximum power transfer. Local and global control strategies have been developed to dampen and impede these oscillations. A modern local control strategy is supplying the automatic voltage regulation (AVR) of the generator with a power system stabilizer (PSS). Modern global control ... -
A Class-E-Based AC-DC converter for PFC applications
(Master thesis; Mastergradsoppgave, 2021-06-22)Connection of nonlinear utility load har increased through resent years and is expected to continue increasing. Nonlinear utility load injects harmonic content into the grid and reduces voltage quality for nearby consumers. To limit harmonic content from nonlinear load, the International Electrotechnical Commission requires power supplies to be designed according to IEC 61000-3-2. Fulfilling this ... -
Solvinkel optimaliserer
(Master thesis; Mastergradsoppgave, 2021-05-18)Snø og andre ting kan reflektere lys på solcellepanelene slik at de produsere mer energi. Refleksjonene kan gjøre slik at den optimale vinkelen til panelene ikke er rett mot solen. Denne rapporten går fort igjennom noen forslag til optimaliseringsalgoritmer for vinklene til solcellepanelene. Videre går den dypere inn på en algoritme som heter «test og sjekk». Kort fortalt går denne algoritmen ... -
Path planning and reactive based control for a quadrotor with a suspended load
(Conference object; Konferansebidrag, 2021-06)This paper presents a solution to quadrotor cargo transportation, more precisely when cargo is suspended as a sling load. The challenge lies in payload position control and swing attenuation, which we approach by dividing the model into subsystems: attitude quadrotor in free flight, and translational and attitude load dynamics. We propose a solution based on reactive control, in the sense that we ... -
Maximum Available Power of Undersea Capacitive Coupling in a Wireless Power Transfer System
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-23)This paper studies the maximum available power of a dissipative capacitive power transfer (CPT) system submerged in seawater. The CPT system's maximum power capability is driven using the network theory, precisely the conjugate-image approach. The equations of the maximum available load power and the system's corresponding efficiency are expressed as a function of the capacitive coupling parameters. ... -
Observations of sunlit N2+ aurora at high altitudes during the RENU2 flight
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-24)We present measurements of sunlit aurora during the launch of the Rocket Experiment for Neutral Upwelling 2 (RENU2) on the 13 December 2015, 07:34 UTC. The in situ auroral conditions coincide with those of sunlit aurora and were characterised by the 391.4 and 427.8 nm N<sub>2</sub> <sup>+</sup> emissions. A correlation between several auroral wavelengths, as measured by a meridian-scanning ... -
PSO and Kalman Filter-Based Node Motion Prediction for Data Collection from Ocean Wireless Sensors Network with UAV
(Conference object; Konferansebidrag, 2021-01)In this paper, we consider a wireless sensor network of nodes at the sea surface drifting due to wind and sea currents. In our scenario an Unmanned Aerial Vehicle (UAV) will be used to gather data from the sensor nodes. The goal is to find a flyable path which is optimal in terms of sensor node energy consumption, total channel throughput between the UAV and sensor nodes, flight time for the ... -
A Class-E-Based Resonant AC-DC Converter With Inherent PFC Capability
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-22)This paper investigates the use of the class-E inverter for power factor correction (PFC) applications. Analytical and state-space models are derived showing the class-E inverter’s capability of achieving inherent PFC operation with a constant duty cycle. The inherent PFC operation limits the controller responsibility to the regulation of the output voltage, which is key for resonant converters with ... -
Improving Geopolymer Characteristics with Addition of Poly-Vinyl Alcohol (PVA) Fibers
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-20)This paper presents the benefits of PVA fibers in improving the mechanical properties of class F fly-ash-based geopolymer concrete. The activator used in the geopolymer was 8M sodium hydroxide (NaOH) and sodium silicate (Na<sub>2</sub>SiO<sub>3</sub>), with a mass ratio of Na<sub>2</sub>SiO<sub>3</sub> to NaOH varied from 1.5 to 2.5. Cylindrical specimens with a diameter of 100 mm and a height of ... -
Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-04)This study analyses the observations of a new type of small-scale aurora-like feature, which is further referred to as fragmented aurora-like emission(s) (FAEs). An all-sky camera captured these FAEs on three separate occasions in 2015 and 2017 at the Kjell Henriksen Observatory near the arctic town of Longyearbyen, Svalbard, Norway. A total of 305 FAE candidates were identified. They seem to appear ...
