We develop converter architectures, controls, and hardware that enable efficient, compact, and high-performance electrical systems.
Research in the Stillwell Power Group spans power-converter topology, digital control, wide-bandgap devices, multilevel and hybrid switched-capacitor conversion, motor drives, and experimental hardware development. Our work is motivated by applications where conventional power-conversion approaches face demanding constraints on efficiency, power density, waveform quality, dynamic performance, voltage, or weight.
Experimental validation is a defining part of our work: we design, fabricate, control, and test converter and motor-drive hardware to understand performance at the system level.
Applications
Our research is driven by applications where power electronics can enable substantial improvements in system performance, mass, efficiency, and capability.
Electric Aviation & Motor Drives
High-specific-power motor drives and converter architectures for high-frequency, low-inductance electric machines, with emphasis on reducing filtering requirements and enabling lightweight electrified propulsion.
Data-Center Power Delivery
Compact point-of-load power converters for high-current, rapidly changing processor loads, including architectures designed for system-in-package and integrated power delivery.
Pulsed Power & Aircraft Systems
Compact, efficient pulsed-power converters for applications such as electrothermal aircraft deicing, where high peak power must be delivered with minimal mass and thermal burden.
Emerging Electrification Applications
Power-conversion technologies for electric transportation, space systems, renewable energy, and other applications demanding exceptional efficiency, density, controllability, or voltage capability.
Enabling Technologies
We combine converter topology, devices, controls, magnetics, and system-level design rather than treating each in isolation.
Multilevel Conversion
Flying-capacitor, ANPC, and other multilevel architectures for high-voltage and high-frequency power conversion.
Hybrid Switched-Capacitor Conversion
Architectures combining switched-capacitor networks and inductive energy transfer for high density and efficiency.
Wide-Bandgap Devices
GaN and SiC devices enabling higher switching frequencies, higher voltage capability, and reduced passive-component size.
Control & Optimization
Digital control, converter modeling, experimental validation, and application-driven system optimization.
Featured Research
ELECTRIC AVIATION & MOTOR DRIVES
High-Power-Density Drives for Low-Inductance Machines
High-frequency slotless electric machines offer attractive specific-power potential for electrified aircraft, but their low phase inductance can produce substantial inverter switching ripple and increase filtering requirements. SPG develops power-converter architectures that address this challenge while preserving the efficiency and weight advantages of advanced electric machines.
Our work has included a seven-level interleaved hybrid active-neutral-point-clamped inverter and now extends to active-filter motor-drive architectures that separate bulk power conversion from high-frequency waveform shaping.
98.8%
Peak Efficiency
7-level I-HANPC prototype
~25%
Lower DC-Link RMS Current
versus a two-level inverter
<5%
Output THD
experimental hardware
DATA CENTER POWER DELIVERY
Point-of-Load Conversion for High-Performance Compute
Modern processors operate at low voltages while demanding increasingly high current and fast transient response. These requirements make the final stage of power delivery a major challenge in next-generation computing systems.
We investigate hybrid switched-capacitor point-of-load converters that move magnetic components away from the high-current output node and create new opportunities for system-in-package and integrated implementations. Research spans converter topology, dynamic modeling, control, component integration, and experimental hardware.
48 V → 6 V
Experimental Conversion
current-sourced hybrid SCC prototype
91.9%
Peak Efficiency
proof-of-concept hardware
SiP / SoC
Integration Focus
magnetics moved away from the output node
PULSED POWER & ELECTRIC FLIGHT
Lightweight Power Conversion for Aircraft Pulse Deicing
Aircraft icing creates a demanding pulsed-power problem: the power electronics must deliver controlled bursts of energy rapidly while adding minimal weight and thermal-management burden to the aircraft.
SPG develops multilevel pulsed-power converters for electrothermal deicing systems. Recent work has demonstrated an eight-level flying-capacitor multilevel converter designed for efficient, high-specific-power energy delivery in electrified aircraft.
3 kW
Prototype Power
8-level FCML converter
>99%
Efficiency
experimental converter
15 kW/kg
Specific Power
lightweight prototype
Explore Our Work
Explore our publications or meet the students and researchers developing these technologies.