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Power Electronics Research Group
Energy,
Power
and
Electronics
Circuits,
Systems,
Signal and
Communications
Principal Investigator: David Perreault
Research Scholars: Prof. Khurram Afridi, Dr. Taylor
Barton
Graduate Students: Minjie Chen, Samantha Gunter,
Wardah Inam, Alex Jurkov, Wei Li, Seungbum Lim, Juan
Santiago. UROPs: Khalil Elbaggari, William Gaviria
The Power Electronics Research Group systematically investigates issues relevant to the production, transformation and application of electrical energy. Specifically, the group is working on power conversion systems that are more energy efficient, more compact and provide higher performance.
Objectives: Develop and apply advanced technologies for improved power conversion, targeting: Methodologies: Power electronics efficiently process and control electrical energy through switched‐mode circuits which utilize:
• Semiconductor devices (power switches and control)
• Passive components (energy storage and filters)
Load Step 10% to 90% of Full load
35
Φ dc-dc Boost Converter
2
34.5
33.5
Output Voltage [V]
1. Very High Frequency Power Conversion
110MHz, 30W, 87% efficient VHF dc‐dc converter for automotive LED lighting
Power vs. Frequency for dc-dc Converters
3
10
Isolated 75 MHz VHF converter with resonant gate drive and integrated coreless transformer
Switched capacitor stage
Resonant buck stage
Microinverter schematic
Power (W)
32
Conventional
Eff. 78%
Current
Practice
1
10
Eff. 87%
30.5
Eff ~70-80%
30
-1
Eff. 74%
Eff. 80%
0
1
0
10
Selected Research Designs
~70%
(Extracted from C. Xiao, "An Investigation
of Fundamental Frequency Limitations for
HF/VHF Power Conversion," Ph.D. Thesis
CPES, Virginia Tech, July 2006)
-1
5
10
6
10
7
10
Frequency (Hz)
2
3
Time [ms]
4
5
6
72%
80%
8
10
Power versus switching frequency performance comparison
Two stage LED driver architecture 32.5
31
2
Resonant PV solar microinverters
providing > 95% CEC efficiency
Magnetics
Φ2 dc‐dc boost converter
33
Eff. 87%
10
10
A two stage 10MHz Grid interfaced LED driver with 90% efficiency, 0.93 pf
LT1371HV
31.5
Recent MIT Designs
Eff. 91%
LT1371HV (simulation)
Much Faster transient response
34
A 75 MHz Isolated Φ2 dc‐dc converter topology used for isolated power supplies
Devices
Circuits
1. Miniaturization and integration of power electronics
2. Better performance: higher efficiency, bandwidth, operating range…
3. Application to improve systems (renewables, lighting, comm., …)
New circuit designs and implementations achieve dramatic increases in power converter switching frequencies into the VHF range (>30 MHz)
• Enables miniaturization and integration
• Provides greatly increased control bandwidth and transient performance
• Achieved through new system architectures, topologies, controls, and passive components
Professor
David J. Perreault
A highly compact 2W, 20MHz, two‐stage 5V‐
1V dc‐dc converter providing > 2000 W/in3 Power density
Size of the converter compared to a US quarter
2. Ultra‐High‐Efficiency Power Electronics
Inefficiencies in power electronics result in tremendous loss of useful energy. Dramatic improvements in the efficiency and loss of power electronics are possible:
• Appropriate topologies and operating methods enable rescaling of designs for extreme high efficiency.
• Application of new semiconductor devices and passives
• New energy processing architectures (e.g., for renewables)
Important applications include:
• Grid‐interface converters for renewables (e.g., solar PV)
• Switched‐mode rectifiers (LED drivers, power supplies…)
• dc‐dc converters (portable electronics, data center power supplies,…)
3. Power Electronics Technology to Benefit Specific Applications
Energy processing at frequencies from dc to RF. Improved power electronics can provide major system‐level benefits in many applications. Target major system‐level improvements, including energy utilization, size, functionality, performance •
Includes many application areas, e.g. transportation, lighting, renewable power generation and conversion, computation, communications, industrial RF heating and processing, medical applications, etc.
Bench
Show
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8
1
2
9
10
1. Sub‐module dc‐dc converter to improve photovoltaic modules
2. 27.12 MHz GaN resonant inverter for load modulation
3. Merged two‐stage converter for low‐
voltage power delivery
4. 75 MHz 85% efficient dc‐dc Converter
5. Custom ICs for Low‐Voltage dc‐dc Converters
6. HF Outphasing inverter system
7. Prototype 30 MHz dc‐dc converter for radar power supply
8. Stacked switched capacitor energy buffer
9. Integrated Passives for EMI Filtering
10.Micro‐fabricated On‐Die Multi‐
Resonant Inductor