Katherine A. Kim with adviser P. T. Krein Hot spotting, a common problem in photovoltaic (PV) panels, accelerates cell degradation and reduces system performance. When partial shading occurs on a string of PV cells, those shaded can become reverse biased. Over time, the reverse-biased cells heat up and can reach high temperatures that cause permanent […]
An Average Modeling Approach of Hybrid Power Systems for Use in Mobile Refrigeration Applications
Yue Cao with adviser P. T. Krein A hybrid power system for mobile refrigeration applications has been designed, modeled, and tested. The system takes in power from the engine via a direct-coupled alternator, with an option to connect to the grid. After power conversion and control, motor drives operate compressors, fans, and blowers comprising the […]
A Motor-Generator and Supercapacitor Based System for Microgrid Frequency Stabilization — CEME Collaborative Research Project with Oregon State University
Rick Crispo with advisers Ted Brekken and Annette von Jouannen Energy storage system hardware is shown to achieve microgrid frequency response. A doubly-fed induction generator is coupled with a squirrel cage induction machine as a motor/generator set to deliver an immediate inertial response to a frequency change. An inverter and supercapacitors deliver short-term energy response. […]
A 3-D Finite Element Analysis of Large-Scale Nonlinear Dynamic Electromagnetic Problems by Harmonic Balancing and Domain Decomposition
Wang Yao with advisers J. M. Jin and P. T. Krein The dual-primal finite element tearing and interconnecting (FETI-DP) method is applied together with the harmonic balance (HB) method and the fixed-point (FP) method to improve the efficiency of three-dimensional finite element analysis (FEA) of large-scale nonlinear dynamic electromagnetic problems. The FETI-DP method decomposes the […]
Inverter Characterization for Intermittent and Peak Duty Motor Drives
Veysel (Tutku) Buyukdegirmenci with adviser P. T. Krein Dynamic electro-thermal inverter and power switch models have been extensively studied in the past, but inverter and drive short-term thermal and electrical capabilities have not been investigated. This research examines inverter short-time ratings, electrical limitations and proper sizing under peak duty applications. Previous electro-thermal models rely on […]
Performance and Efficiency Enhancement of Induction Machine Drives: Duality-Based Control to VSI and CSI Control
Srikanthan Sridharan with Adviser P. T. Krein The duality between the two-level voltage sourced inverter (VSI) and the current sourced inverter (CSI) is examined for performance and efficiency enhancement of induction motor drives over wide operating conditions. A loss minimization algorithm is developed using a comprehensive loss model to achieve optimum flux for minimizing system-level […]
Stator Configuration Constraints on Electric Machine Performance
Matthew Magill with Adviser P. T. Krein Conventional polyphase machine windings were designed to set the operating speed and minimize spatial harmonics when operated under utility excitation. As power electronic sources have replaced line feeds in most applications, refinements in stator and rotor slot design shapes have been considered for increased performance. The stator winding […]