Engineering Commons^™

Modeling And Control Of Power Electronics Interfaced Load For Transmission Power Network Analysis, Shuyao Wang

Doctoral Dissertations

The penetration level of power electronics (PE) interfaced loads has been gradually increasing in recent years. It is beneficial to equip the electric load with a PE interface since it allows for more advanced control of the load performance. Furthermore, the increasing penetration of PE interfaced loads will bring both challenges and opportunities to power network resilience and reliability.

However, the lack of modeling and control design for PE interfaced load units in the transmission-level power network analysis, especially for these high-penetrated high-power-rating load applications, limits the accuracy of evaluating the dynamic performance and stability status of the power network. …

Design Considerations For Gan-Based Photovoltaic Inverter And Solid-State Circuit Breaker, Zhe Yang

Doctoral Dissertations

Featuring low specific on-state resistance, high switching speed, and zero reverse recovery current, Gallium Nitride (GaN) transistor is becoming one of the most promising devices for power electronic applications. This dissertation presents some design considerations for photovoltaic (PV) inverters and solid-state circuit breakers (SSCBs) using GaN devices. Several related challenges and solutions will be discussed in this dissertation.

First, the filter design for full bridge PV inverter is discussed, which includes the design and optimization of individual inductor and overall power filter. The inductor design takes the fringing effect into account, and achieves optimal design with simple algorithm. Then, the …

Switching Performance Evaluation, Design, And Test Of A Robust 10 Kv Sic Mosfet Based Phase Leg For Modular Medium Voltage Converters, Xingxuan Huang

Doctoral Dissertations

10 kV SiC MOSFETs are one of the most promising power semiconductor devices for next-generation high-performance modular medium voltage (MV) converters. With extraordinary device characteristics, 10 kV SiC MOSFETs also bring a variety of challenges in the design and test of MV converters. To tackle these inherent challenges, this dissertation focuses on a robust half bridge (HB) phase leg based on 10 kV SiC MOSFETs for modular MV converters. A baseline design and test of the phase leg is established first as the foundation of the research in this dissertation.

Thorough evaluation of 10 kV SiC MOSFETs’ switching performance in …

Modeling And Control Of A 7-Level Switched Capacitor Rectifier For Wireless Power Transfer Systems, Spencer Cochran

Doctoral Dissertations

Wireless power continues to increase in popularity for consumer device charging. Rectifier characteristics like efficiency, compactness, impedance tunability, and harmonic content make the multi-level switched capacitor rectifier (MSC) an exceptional candidate for modern WPT systems. The MSC shares the voltage conversion characteristics of a post-rectification buck-boost topology, reduces waveform distortion via its multi-level modulation scheme, demonstrates tank tunability via the phase control inherent to actively switched rectifiers, and accomplishes all this without a bulky filter inductor. In this work, the MSC WPT system operation is explained, and a loss model is constructed. A prototype system is used to validate the …

Characterization Techniques And Cation Exchange Membrane For Non-Aqueous Redox Flow Battery, Kun Lou

Doctoral Dissertations

The motivation of this work comes from one of the major problems of emerging non-aqueous flow battery (NAFB) that a separator or membrane which facilitates conductivity and blocks redox species crossover does not exist. Although many aspects of principles can be mirrored from mature fuel cell and aqueous flow battery, it is found that some well-defined membrane properties in aqueous systems such as swelling, transport and interactions are different in non-aqueous solvents to some extent. However, the approach of this work does follow the way perfluorosulfonate ion exchange membrane (PFSA) facilitated development of fuel cell and aqueous flow battery in …

Model-Based And Model-Free Approaches For Power System Security Assessment, Mariana Magdy Mounir Kamel

Doctoral Dissertations

Continuous security assessment of a power system is necessary to insure a reliable, stable, and continuous supply of electrical power to customers. To this end, this dissertation identifies and explores some of the various challenges encountered in the field of power system security assessment. Accordingly, several model-based and/or model-free approaches were developed to overcome these challenges.

First, a voltage stability index, named TAVSI, is proposed. This index has three important features: TAVSI applies to general load models including ZIP, exponential, and induction motor loads; TAVSI can be used for both measurement-based and model-based voltage stability assessment; and finally, TAVSI is …

Grid-Forming Converter Control Method To Improve Dc-Link Stability In Inverter-Based Ac Grids, Ishita Ray

Doctoral Dissertations

As renewable energy sources with power-electronic interfaces become functionally and economically viable alternatives to bulk synchronous generators, it becomes vital to understand the behavior of these inverter-interfaced sources in ac grids devoid of any synchronous generation, i.e. inverter-based grids. In these types of grids, the inverters need to operate in parallel in grid-forming mode to regulate and synchronize their output voltage while also delivering the power required by the loads. It is common practice, therefore, to mimic the parallel operation control of the very synchronous generators that these inverter-based sources are meant to replace. This practice, however, is based on …

Wide Area Damping Control To Improve Transient Stability And Hardware-In-The-Loop (Hil) Implementation, Ibrahim Abdullah Altarjami

Doctoral Dissertations

In this dissertation, the impacts of WADCs on system transient stability are investigated, including system separation prevention under large disturbances and tie-line power transfer limit enhancement with consideration of a three-phase fault on one of the two tie-lines. The full Saudi power grid model in PSS/e is reduced for the real-time simulation on the Real-Time Digital Simulator (RTDS), and thus the developed WADCs can be tested in a controller hardware-in-the-loop environment in the future. The RTDS model is validated by comparing the full PSS/e model and the reduced PSS/e model under different contingencies. The WADCs are designed using a measurement-driven …