Essays about: "Dynamic instabilities"

Showing result 1 - 5 of 20 essays containing the words Dynamic instabilities.

  1. 1. Off-State Stress Effects in AlGaN/GaN HEMTs : Investigation of high-voltage off-state stress impact on performance of and its retention in hybrid-drain ohmic gate AlGaN/GaN HEMTs

    University essay from KTH/Skolan för elektroteknik och datavetenskap (EECS)

    Author : Ivan Krsic; [2023]
    Keywords : HEMT; GaN; off-state stress; memory effects; drain leakage current; dynamic RDSon; threshold voltage instabilities; charge redistribution; HEMT; GaN; stress i avslaget tillstånd; minneseffekter; läckströmmen; dynamisk RDSon; instabiliteten hos styrets tröskelspänning; omfördelningen av laddningar;

    Abstract : High electron mobility transistors (HEMTs) realized using AlxGa1-xN/GaN are relatively new technology which is prominent for high-speed and high-power applications. Some of the main problems with this technology were identified as dynamic RDSon, current collapse and threshold voltage instabilities due to the off-state stress. READ MORE

  3. 2. Frequency Stability of Power Electronic Based Power System with 100% Renewable Energy.

    University essay from KTH/Skolan för elektroteknik och datavetenskap (EECS)

    Author : Abdullah Albalali; [2022]
    Keywords : energy storage; frequency control; synchronous generators; distributed power generation; virtual synchronous machine VSM ; PSCAD.; energilagringssystem; frekvenskontroll; synkrona generatorer; distribuerad kraftproduktion; virtuell synkron maskin; PSCAD.;

    Abstract : The modern power system is aiming to progress away from conventional synchronous machine  based power generation towards converter dominated system that leads to extensively high penetration of renewable energy such as wind and PV. This transition of modern power system toward converter based renewable energy comes with new challenges as the conventional synchronous generation is being replaced by converter based power system (CBPS). READ MORE

  4. 3. Analytical Investigation of Planetary Gears Instabilities and the Impact of Micro-Macro Geometry Modifications

    University essay from KTH/Farkostteknik och Solidmekanik

    Author : Hamza Oudich; [2020]
    Keywords : Planetary gears; Instabilities; Resonance; Vibration; dynamic response; Spectral Iterative Method; Modal analysis; Static and dynamic transmission error; Gear mesh stiffness; Macro and micro-geometry; Phasing;

    Abstract : Due to their large torque-speed ratio and transmission efficiency, planetary gears are widely used in the automotive industry. However, high amplitude vibrations remain their critical weakness, which limits their usage especially when new strict noise legislations come into action. READ MORE

  5. 4. CFD analysis of stepped planing vessels

    University essay from KTH/Mekanik

    Author : Toni Kokkonen; [2018]
    Keywords : Computational Fluid Dynamics CFD ; Ship hydrodynamics; Planing hull; Stepped hull; STAR-CCM ; Overset mesh; Volume of fluid VOF ; Reynolds averaged Navier-Stokes equations RANS ; Dynamic instabilities;

    Abstract : High speed planing hulls are currently widely used for example in recreational and emergency vessel applications. However, very little CFD research has been done for planing vessels, especially for those with stepped hulls. A validated CFD method for planing stepped hulls could be a valuable improvement for the design phase of such hulls. READ MORE

  6. 5. Gotland as a microgrid -  Energy storage systems frequency response in grids with high level of renewable energy penetration

    University essay from Uppsala universitet/Elektricitetslära

    Author : Firas Daraiseh; [2018]
    Keywords : Energy Storage System; Frequency Response; Gotland; Microgrid; Wind Curtailment; PSS E;

    Abstract : The Swedish island of Gotland , situated about 100 km from mainland Sweden in the Baltic Sea, represents a power system with a high wind power penetration. The island is connected to the mainland Sweden exclusively via two HVDC cables that provide the only source of active power and frequency control. READ MORE