Sökning: "Andreas Petersson"
Visar resultat 1 - 5 av 8 avhandlingar innehållade orden Andreas Petersson.
Sammanfattning : To understand the growth of continental crust, the balance between juvenile mantle derived extraction, infracrustal reworking and crustal recycling, needs to be estimated. Since the beginning of the century, the use of coupled in situ zircon U–Pb, Lu–Hf and O isotope analyses as a tool to address these questions have increased exponentially. LÄS MER
Sammanfattning : This thesis deals with the analysis, modeling, and control of the doubly-fed induction generator (DFIG) for wind turbines. Different rotor current control methods are investigated with the objective of eliminating the influence of the back electromotive force (EMF), which is that of, in control terminology, a load disturbance, on the rotor current. LÄS MER
Sammanfattning : This thesis deals with the analysis, modeling, and control of the doubly-fed induction machine used as a wind turbine generator. The energy efficiency of wind turbine systems equipped with doubly-fed induction generators are compared to other wind turbine generator systems. LÄS MER
4. Approximating Stochastic Partial Differential Equations with Finite Elements: Computation and Analysis
Sammanfattning : Stochastic partial differential equations (SPDE) must be approximated in space and time to allow for the simulation of their solutions. In this thesis fully discrete approximations of such equations are considered, with an emphasis on finite element methods combined with rational semigroup approximations. LÄS MER
Sammanfattning : In order to simulate solutions to stochastic partial differential equations (SPDE) they must be approximated in space and time. In this thesis such fully discrete approximations are considered, with an emphasis on finite element methods combined with rational semigroup approximations. There are several notions of the error resulting from this. LÄS MER