Penglin Niu with adviser Patrick L. Chapman This year, we have been working on three potential human motions for energy harvesting and design of one energy-harvesting device for each motion. Arm swing, horizontal foot movement, and up-down center-of-gravity movement during walking are analyzed for energy harvesting. Given commonality among the three motions, a general linear […]
Performance Limits of dc-dc Converters and Control
Grant Pitel with adviser Philip T. Krein Switched electrical systems such as switch mode power supplies (SMPS) have response times limited by their time-dependent states: inductor current and capacitor voltage. Tight control over state response has a long history in dynamic power electronic applications that must track quick reference changes and reject various disturbances. Traditional […]
Integrated Machines and Drives
Brett Nee with adviser Patrick L. Chapman Increasingly, power electronics drives are providing control over machines’ torque/ speed. Integration of the drive and the machine can lead to improvements in cost and performance. Research is being conducted in system integration, utilizing each subsystem’s important characteristics to aid in the design of the other subsystems, for […]
Sensorless Current Mode Control to Stabilize an Input-Series-Output- Parallel Converter
Jonathan Kimball with adviser Philip T. Krein Many solutions have been proposed for power converters with high conversion ratios. The performance and efficiency of nonisolated converters degrades significantly when the ratio between input and output voltage exceeds 4:1. Isolated converters can operate with an arbitrary ratio by changing a transformer turns ratio, but higher turns […]
Analysis and System-On-a- Chip Implementation of Digitally Controlled Multi-Port DC-DC Converters
A power management architecture that uses digital phase control to maximize the advantages of digital control in the lowvoltage power electronics field is proposed. The implemented architecture consists of a 7-bit pipelined ADC, a PI digital controller, a digital phase controller, a digital PWM and a CMOS power device. The implemented architecture design has been […]
Spectrum Management for PWM Switching Signals
Xin Geng with adviser Philip T. Krein Switching power conversion for portable communications, personal digital assistants and most other electronic products is controlled through PWM. Since PWM produces strong components at the switching frequency and its multiples, one objective of this project is to study spectral characteristics of PWM for purposes of electromagnetic interference (EMI) […]
Algorithm to Determine Minimum Contingency Set in Voltage Collapse Scenarios
Jeremiah D. Smith with adviser Peter Sauer This investigation stems from the relationship between real power load and voltage at transmission voltage levels, and the occurrence of steady-state bifurcations within a system. It deals with only static analysis, neglecting the dynamics that can contribute to voltage instability. The assumption is that changes in system parameters, […]
Optimization of Fuel-Cell Power Converters
Nicholas Benavides with adviser Patrick L. Chapman Proton exchange membrane fuel cell systems have not yet penetrated the lowpower (<50 W) portable energy source market, largely due to complexity of control and the balance of plant systems required. Even though the fuel cell and fuel container may scale down well, the pumps, blowers, and power […]
Commutation Technique for High- Frequency-Link Switching Power Converter Based on State-Machine Control
Robert S. Balog Jr. with adviser Philip T. Krein This invention is a technique that resolves current commutation challenges in various types of ac-ac switching power converters. It also applies to inverters and rectifiers with high-frequency links. Direct ac-ac converters such as matrix converters and cycloconverters benefit from the approach. This technology commutates load current […]
Autonomous Local Controls in a Distributed DC Power System
Robert S. Balog Jr. with adviser Philip T. Krein Direct-current power systems have long been the standard for power distribution in many applications where reliability is the primary concern such as telecommunication and space systems. In Navy ships, where reliability is also of utmost importance, interest in integrating and managing total system energy resources has […]