Noise Control in Novel Power Electronics for SMART Grid

    Research output: ThesisPhD Thesis - Research UT, graduation UT

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    As society and technology are developing, the amount of electrically powered
    devices is ever increasing. The traditional electrical grid, structured in a hierarchical way, is not capable of sustaining the rapid development and implementation
    of a more dynamical consumer. By incorporating solar panels and
    wind turbines at farm, businesses and even households the consumer becomes a
    producer as well. This transforms the conventional grid into a more dynamical
    and also distributed one. The project of which this thesis was a part of, deals
    with the integration of renewable energy by applying a new architecture that
    enables point-to-point power transmission and thus reduces instabilities and
    improves dynamical behavior. The key objective for the University of Twente
    (UT) is to find the best options for reducing interference, associated with fast
    switching semiconductors as applied in the novel converter type.
    This thesis starts with the development of a theoretical model based on the
    control signals applied to switching power devices. The model can be used to
    predict and estimate the conducted Electroagnetic Interference (EMI) generated
    in switching devices using sinusoidal Pulse Width Modulation (sPWM)
    waveforms. The model was verified in a conducted emission measurement.
    Combining the model with a radiated emission estimation model, gives a description
    of a noise source that is applied in the newly developed multi-level
    For application in multi-level converters a sPWM generator was developed,
    which with its flexibility is used to perform measurements on Galium-Nitride
    (GaN) and Silicon-Carbide (SiC) based DC/AC converters, and multilevel converters.
    In case of conducted EMI measurements, the results were used to verify
    the theoretical model. In case of the magnetic radiated EMI measurements,
    a time domain measurement technique was developed that is comparable to
    using a traditional EMI receiver. The technique reduces measurement times
    from minutes to several seconds per orientation and placement. In case of large
    stacked multi-level converters it was deemed necessary to asses the magnetic
    radiation produced in such a structure. The electric field measurements are
    eventually used together with the developed mathematical model to determine
    the effective radiation efficiency of the system under test.
    The developed technique of determining the effective radiation efficiency,
    together with the concept for optimal placement of EMI in fully integrated systems are considered to be part of the main contributions of this thesis and
    can be seen as Mitigation through EMI placement. Another mitigation technique,
    which is a fairly classical Electromagnetic Compatibility (EMC) one,
    consist of implementing a filter along the propagation path of the disturbance.
    Part of the research objectives was developing behavioral circuit models based
    on full wave model and thus optimized filters implementing nano-crystalline
    This thesis contributes with the development of an automated method for
    back annotating field effects into equivalent circuit simulations. Part of this
    work was the development of Gauss-Newton optimization algorithm that can fit
    impedance curves to equivalent circuit elements. This was applied to measurements
    and full-wave 3D simulations of relatively simple components like capacitors,
    which showed optimal capacitor placement can be investigated through
    circuit simulations rather then Electro-Magnetic (EM) field simulations. Extending
    the research to more complex structures and components, required the
    development of a 3D full wave high frequency models. This has been done for
    a two phased sectionally winded Common Mode Choke (CMC), incorporating
    complex permeabilities through a dispersion model.
    Overall it can be concluded that this thesis has contributed to the development
    of the future electrical grid, by investigating components that are
    attributed to the Multifunctional Multilevel Modular Converter (M3C), which
    is considered to enable the development of the ’smart grid ’. Much work still
    needs to be done, from refining and applying the developed measurement techniques
    to larger and fully integrated systems to developing more accurate and
    faster fitting algorithms for determining equivalent circuit component values.
    Also the effect of proposed mitigation techniques on various functionalities of
    the M3C have to be investigated.
    Original languageEnglish
    QualificationDoctor of Philosophy
    Awarding Institution
    • University of Twente
    • Leferink, Franciscus Bernardus Johannes, Supervisor
    Thesis sponsors
    Award date11 Oct 2019
    Place of PublicationEnschede
    Print ISBNs978-90-365-4866-3
    Electronic ISBNs978-90-365-4866-3
    Publication statusPublished - 11 Oct 2019

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