Design six-pulse rectifiers with LC filters to meet three different specifications. The input is threephase AC with a line-to-line RMS voltage of 208 V and a frequency of 60 Hz. The variable load
can be modeled as a resistance that can vary between 100 Ω and 500 Ω.
Design 1: Inexpensive Design
• Total component cost < $47
• Efficiency > 98% for all load conditions
• Load voltage ripple < 1% (peak-to-peak/average) for all load conditions
• AC source power factor > 0.89 for all load conditions
Design 2: High Performance Design
• Total component cost < $75
• Efficiency > 98.5% for all load conditions
• Load voltage ripple < 0.25% (peak-to-peak/average) for all load conditions
• AC source power factor > 0.93 for all load conditions
Design 3: Aircraft Design
For this design, assume that the AC source has a frequency of 400 Hz.
• Total component cost < $50
• Efficiency > 98.8% for all load conditions
• Load voltage ripple < 0.1% (peak-to-peak/average) for all load conditions
• AC source power factor > 0.945 for all load conditions
Selecting Components
Use Digikey or Mouser to find components and get their prices. You may use the prices for bulk
purchases. Include the site you found the component and its part number in your submission.
Make sure that you select components with adequate current and voltage ratings for all operating
points. Use the datasheets to check the specifications and ratings. You just need to select
components; you do not need to purchase components or build a prototype. You may use some of
the same components for multiple designs. For example, you might use the same capacitor for
Designs 1 and 3 or the same inductor for Designs 2 and 3.
Diodes
Use Digikey part number RFN5BM3SFHTLTR-ND. Assume Vf = 0.74 V and rd = 80 mΩ. This
diode has a peak voltage rating of 350 V, an average current rating of 5A, and a peak current rating
of 50 A. These values must not be exceeded. The diodes can be purchased for $0.80 each. (When
calculating the total component cost, remember that multiple diodes are required.)
Inductors
Use a fixed inductor, NOT a common mode choke. Make sure that the inductor is rated for
adequate current. Since the frequencies that we are dealing with are relatively low, you can use
the inductor’s DC current rating as the limit for your RMS inductor current. You may combine
multiple inductors in parallel or series, if needed. If you cannot find the DCR or current rating for
an inductor in its datasheet, do not use that inductor.
Capacitors
Make sure that the capacitor is rated for adequate voltage and RMS ripple current. You may
combine multiple capacitors in parallel or series, if needed. Since the frequencies that we are
dealing with are relatively low, if the capacitor has the ESR or ripple current specified for two
different frequencies, use the lower frequency (either 100 Hz or 120 Hz). If you cannot find the
ESR, current rating, or voltage rating for a capacitor in its datasheet, do not use that capacitor.
Submission Requirements
Submit both your code and a summary of the designs. Your code should take the following inputs:
• Diode forward voltage
• Diode resistance
• Diode average current rating
• Diode peak current rating
• Diode reverse voltage rating
• Inductor inductance
• Inductor DCR
• Inductor RMS current rating
• Capacitor capacitance
• Capacitor ESR
• Capacitor voltage rating
• Capacitor RMS current rating
If you use Matlab, use the code posted on eLearning as the first lines of your code so that I can
easily copy in my test cases to see whether your code works. You can change the values of the
different variables to reflect your design, but do not change the names of the variables.
Your code should do the following:
• Calculate the range of efficiencies across the range of loads
• Calculate the range of power factors across the range of loads
• Calculate the range of load voltage ripples (as the peak-to-peak ripple divided by the
average load voltage) across the range of loads
• Verify that no current or voltage ratings are exceeded across the range of loads
• Verify any assumptions about continuous or discontinuous current
Your summary of the designs should include the following for each design:
• Part numbers for each component and where you found each component (Digikey or
Mouser)
• Ratings and specification for each component
• Cost for each component
• Total component cost
• Graph* of efficiency versus load resistance
• Graph* of power factor versus load resistance
• Graph* of load voltage ripple (peak-to-peak as a percentage of average load voltage)
*For the graphs, use enough points that the curves look smooth. I should not be able to count the
number of points that you used. Also, make sure that axes are labeled and units are shown.