Power Factor Correction in an Electronic Ballast

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Power Factor Correction in an Electronic Ballast

• Using the SiC Schottky Diode

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Team

• Team Leader
• Clinton Livingston
• Team Members
• Travis Brignac
• Robin Kelley
• Advisor
• Dr. Mazzola

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Comparison Si pn vs. SiC Schottky

• Reverse biased pn junction diode does not turn
  off fast enough during switching
• This is due to the removal of excess carries from
  the depletion region
• Causes reverse recovery transient
• SiC Schottky diodes do not need to remove excess
  carries from the depletion region
• Eliminates reverse recovery transient.
• Allows for higher operating frequencies

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System / Hardware
120V AC
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EMI Filter / AC Rectifier
P-Spice Schematic
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EMI Filter Waveforms
Fully Rectified Sine Wave 169V pk.
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Power Factor Correction
Why?
Input Voltage/Current before PFC

• Conduction Cycles of Diodes in Rectifier
• Current spikes and is out of phase with the
  voltage
• Very poor power factor

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Power Factor Correction
Basic Schematic for PFC
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PFC Waveforms (Before Integration)
Input Voltage and Current
Average Current for PFC
Significant Noise Need
filtering to Reduce
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PFC Waveforms (Before Integration)
Boosted Output Voltage 120 Vrms in 282 Vdc out
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DC-AC Inverter
P-Spice Schematic
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Inverter Simulation Results
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Inverter Waveforms (Before Integration)
First Semester Test Results
Lamp Voltage f200kHz
Resistive Load f100kHz
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Inverter Waveforms (Before Integration)
Second Semester Test Results for Resistive Load
Output Voltage/Current
M1 Voltage/Current
M2 Voltage/Current
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Inverter Waveforms (Before Integration)
Second Semester Test Results for Lamp Load
Output Voltage/Current
M1 Voltage/Current
M2 Voltage/Current
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Integration Results
Packaging Market Ballast vs. First Hardware
Integration
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Integration Results
Test Result for Integrated PFC Circuitry
Input Voltage and Current Waveforms
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Integration Results
Test Result for Integrated DC-AC Inverter
M1 Voltage/Current After Integration
M2 Voltage/Current After Integration
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Integration Results
Test Result for Integrated DC-AC Inverter
(Continued)
Voltage and Current Waveforms before integration
Voltage and Current Waveforms after integration
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Constraints vs. Results
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Current / Future Work

• 4th Revision of PFC
• Additional Filtering
• 3rd Revision of Inverter
• Adjust for Reverse Recovery Problems
• Layout Revisions
• Smaller Package
• Final Testing

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Questions?
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