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The Grainger Center for Electric Machinery and Electromechanics update, May 2007. P. Krein, P. Chapman Grainger Center for Electric Machinery and Electromechanics Dept. of Electrical and Computer Engineering University of Illinois at Urbana-Champaign. Introduction.
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The Grainger Center for Electric Machinery and Electromechanicsupdate, May 2007 P. Krein, P. Chapman Grainger Center for Electric Machinery and Electromechanics Dept. of Electrical and Computer Engineering University of Illinois at Urbana-Champaign
Introduction • The Grainger Center for Electric Machinery and Electromechanics (CEME) a large endowed academic program. • Funds leverage industry and government support. • About 25 graduate students and many additional undergraduates. • Research on machines, drives and drive controls, and advanced energy processing.
Highlights • Emphasis this year: machine design and system interfaces. • Distributed generation and controls for dispersed energy. • Future-oriented energy conversion efforts – disruptive energy innovations and student projects on energy. • High-performance power conversion.
Machine Design • A machine today is not just steel and copper. • Add to the mix of choices: • Silicon devices for switching andcontrol. • Advanced steels. • Exotic magnetic materials. • Superconductors. • Nanoengineered materials. • New thermal technologies.
Machine Design • Magnetic equivalent circuit approach as a design alternative to finite element analysis. • Seeking speed and easy extension to 3D.
Machine Design • Project examples: • Tim O’Connell, computer methods for exact field analysis
Themes • Best use of technology and hardware • Best performance for power conversion • Best match between power electronic circuits and controls and the applications • Nonlinear controls for both analog and digital implementations of motor controls and power electronics • System-level design and performance • 3rd generation digital controls for power electronics
Solar House • CEME is providing electrical engineering support to the 2007 Solar Decathlon. • Object is to build a solar-powered house that is self-sustaining, affordable, and appealing.
Metal Advanced Power Devices • Collaborating with material scientists for power-on-chip integrated circuits • High performance gallium-nitride based semiconductors • Miniaturized filter components
Modulation for EMI Supression • Predistortion pulse-width modulation can be designed to performance spectrum management.
Reconfigurable Inductors • Use power electronics to modify magnetic inductors • Improve output of a solar panel by 18% during cloudy days
Efficient Models of Machines • Developing software to automate the analysis electric machines • We include more detail, with less computation • Over 1000-fold computation time improvement
System-Level Machine Applications • Machines with integrated magnetics. • Machines for reciprocating generation.
Disruptive Energy Innovations • One-stage grid inverter for alternative energy. • Disruption: technology that scales down to small modules for broad use. • Today, solar power costs are split almost equally between semiconductor cells, power conversion, and mounting and installation. • Most outside research emphasizes semiconductor advances instead of a complete energy system. • Significant breakthroughs, with SmartSpark Energy Systems, on control and energy storage.
Collaborative Network • University of California (Berkeley) • Georgia Tech • Ohio State • Oregon State • Purdue • University of Wisconsin (Madison)
Geometric Control Examples • Dc-dc buck converter, 12 V to 5 V nominal. • L = 200 uH, C = 10 uF, 100 kHz switching.
Fixed Duty Ratio • Steady state, fixed duty ratio. • This shows the inductor current and ten times the normalized capacitor voltage. • The “best” solution given fixed 100 kHz switching.
Result in State Space • Same data plotted in state space.
Response to Step Line Input • Line step from 12 V to 15 V at 42 us. • Duty ratio adjusts instantly to the right values. (This would happen in open-loop SCM.) • Transient in voltage occurs.
State Space • State space plot shows how much the behavior deviates.
Same Step – Different Control • This is a geometric control, with the switch set for minimal dynamic disruption. Same line step.
State Space • The step is cancelled perfectly – essentially in zero time.
More Sample Projects • Microgrids for high-reliability telecom power. • Bidirectional power supplies. • Models for intelligent gate controls in IGBT inverters. • Power harvesting technology. • Education in electric machines.