PhD student Srikanthan Sridharan with advisor P. T. Krein The use of LC filters between inverter and motor terminals results in undesirable resonant oscillations in motor voltages and currents. Passive damping methods employing physical resistors to suppress these oscillations contribute to additional losses. So, loss-less active damping methods with virtual resistors have been explored as […]
Investigation of Electronic Pole-Changing in High Inverter Count Induction Machines
PhD student Matthew Magill with advisor P. T. Krein Continuing improvements in cost/performance/complexity trade-offs in power electronics allow increasingly complicated inverter arrangements to be used to increase electric machine system performance without substantial cost requirements. In addition to improved system reliability and decreased component ratings, a large number of electrical inputs allows for the electronic […]
New ECE 464 Text: Elements of Power Electronics, 2nd ed.
The second edition of Elements of Power Electronics, by Professor Philip T. Krein, is designed to be used for undergraduate and graduate courses and presents power electronics in its many facets. The objective is to lay a foundational base from which engineers can examine the field and practice its unusual and challenging design problems. It […]
Network Decomposition-Based Secondary Frequency Control of a Lossless Microgrid
PhD student Madi Zholbaryssov with advisor A. Domínguez-García We address the microgrid generation control problem, with special emphasis on frequency regulation of lossless microgrids with inverter-interfaced generators. First, we propose a control strategy based on a decomposition of the microgrid network into subnetworks which form an acyclic graph. Each subnetwork is controlled independently from the […]
Finite-Time Distributed Frequency Regulation for Islanded AC Microgrids
PhD student Stanton Cady with advisor A. Domínguez-García This work develops and implements a distributed control architecture for regulating frequency in islanded ac microgrids. By combining computations performed by local generator controllers with information received from those of nearby generators, functionality that typically requires a centralized computer connected to each generator by a communication network […]
A Two Time-Scale Approach to Voltage Regulation in Unbalanced Distribution Systems
Brett Robbins with advisor A. Domínguez-García The introduction of distributed energy resources (DERs), e.g., plug-in hybrid electric vehicles and photovoltaic (PV) installations, in distribution systems results in operational scenarios that these systems were not designed to handle. Interestingly, by properly controlling the power electronic grid interfaces of these DERs, they can provide reactive power support […]
A Stochastic Approach to Asynchronous Differential Power Processing for True Maximum Power Point Tracking of Photovoltaic Sub-Modules
MS student Felix Hsaio with advisor R. Pilawa-Podgurski Photovoltaic (PV) systems produce maximum power when their modules (panels) and sub-modules are biased at the correct voltages and currents. These operating points change dynamically with factors such as insolation, shading, temperature, and panel age, so power converters must perform maximum power point tracking (MPPT). In differential […]
Differential Processing for Improvements in Solar Array Energy Harvest
MS student Jason Galtieri with advisor P. T. Krein Mismatch among PV cells accounts for a significant proportion of annual energy reduction in solar arrays. Sources of mismatch include cell degradation, poor factory binning, and non-uniform irradiance due to shading. Differential power processing (DPP) has the capability to mitigate all three of these sources by […]
Fast Modeling of Solar Costs and Sensitivity
MS student Mark Hagge with advisor P. T. Krein A discounted cash-flow model of solar panel installations was built in Excel to provide a direct, readily understood, and open-cost analysis of photovoltaic (PV) systems. It can be used to approximate the economic merit of a particular technological improvement over a wide range of model assumptions. […]