User’s Manual
For the
Flywheel-based Voltage Sag
Correction System
By Gavin Abo, Nate Stout, and Nathan Thomas
Table of Contents
Definitions..................................................................................................................Page 1
Safety Issue’s .............................................................................................................Page 1
Notes ..........................................................................................................................Page 1
Maintenance ...............................................................................................................Page 2
Additional Information ..............................................................................................Page 2
Connection Procedure ................................................................................................Page 3
Startup Procedure .......................................................................................................Page 3
Connection Diagram ..................................................................................................Page 4
Test Plan for FVSCS ..................................................................................................Page 5
Definitions:
FVSCS – Flywheel-based Voltage Sag Correction System
AMPS – Analog Model Power System
SVPWM – Space Vector Pulse Width Modulation
STPWM – Sine Triangle Pulse Width Modulation
Shorting bar – device used to short-circuit the capacitors in order to keep them from
acquiring a voltage while not in use.
Converter – IGBT-based active rectifier/inverter
Converter 1 – SVPWM converter
Converter 2 – STPWM converter
Relay R1 – The relay that shorts around the current limiting resistors
Relay R2 – The relay that remove the DC link charging supplies and connects the
AMPS.
LEM – voltage or current measuring device
PLL – Phase-locked loop
I/M – Induction Machine connected to the flywheel
PSCAD/EMTDC – Power System Computer Aided Design / Electromagnetic Transients
including DC
Flashing – writing to the Flash, or permanent memory of the DSP.
VOM – Volt-Ohm Meter (multimeter)
Mathematical definitions:
Theta – the angle of the magnetic field in the induction machine relative to the x-axis
Parks Transform – a mathematical transform used to turn three-phase (abc quantities)
into two-phase (dq quantities)
Safety Issue’s
 Verify the capacitors have no charge on them by placing the shorting bars across the
leads of each capacitor when not in use. Make sure to remove the shorting bars
before using the FVSCS.
 Make sure the Plexi-Glas is attached on all four sides of the cart.
 Two people need to be in the AMPS room when the power is on.
Notes
Connection to the AMPS should be made far enough away from the source that the sag
created does not trip the SEL relays.
This system only works on symmetrical (three-phase) sags. It will not work properly for
asymmetrical sags.
The JTAG connector to flash the DSP’s does not stay on very well. It is recommended
that the user secure it while flashing the DSP’s. Failure to secure it may result in damage
to the flash, which could render the processor unusable.
The system has not been fully integrated and tested. Use at your own risk.
Maintenance
The IGBT’s on the SVPWM converter board will be used a lot more than on the STPWM
converter board. The boards should be exchanged after every 1000 hours of use. This
requires reflashing the DSP’s on each board.
The included test plan should be run after every 1000 hours of use or if any problems
occur.
For more information on:
PWM methods: Electric Motor Drives: Modeling, Analysis, and Control By R. Krishnan
The theory behind our design: Satish’s Thesis – See Documentation CD or Brian Johnson
Connection Procedure
1. Turn power strip off.
2. Connect the 48V DC wall mount power supply to the cooling fan connection.
3. Remove the capacitor shorting bars from both capacitors
4. Connect the BLACK banana jacks of the capacitors together.
5. Connect the BLACK banana jack of one capacitor to ground.
6. Connect the Positive DC power supply to the RED banana jack of capacitor 1.
7. Connect the Negative DC power supply to the RED banana jack of capacitor 2.
8. Connect the ground wire of BOTH DC charging supplies to ground.
9. Connect the RED banana jack of capacitor 1 to ___ of converter 1 and ___ of
converter 2.
10. Connect the RED banana jack of capacitor 1 to ___ of converter 1 and ___ of
converter 2.
11. Connect the L1 connection of the I/M to the T1 of converter 1
12. Connect the L2 connection of the I/M to the T2 of converter 1
13. Connect the L3 connection of the I/M to the T3 of converter 1
14. Connect the T1 of converter 2 to the X1-1 of the transformer
15. Connect the T2 of converter 2 to the X2-1 of the transformer
16. Connect the T3 of converter 2 to the X3-1 of the transformer
17. Connect the X1-4, X2-4, and X3-4 of the transformer to ground.
18. Short X1-2 and X1-3 together.
19. Short X2-2 and X2-3 together.
20. Short X3-2 and X3-3 together.
21. Connect the J11-A (Connection point J11, A-phase) of AMPS to H1-1 of the
transformer.
22. Connect the J14-A of AMPS to H1-4 of the transformer.
23. Connect the J11-B of AMPS to H2-1 of the transformer.
24. Connect the J14-B of AMPS to H2-4 of the transformer.
25. Connect the J11-C of AMPS to H3-1 of the transformer.
26. Connect the J14-C of AMPS to H3-4 of the transformer.
27. Plug in the Cooling fan power supply and both DC power supplies.
Start up Procedure
Start up the AMPS.
Close the line breakers.
Turn on the power strip.
Initiate a symmetrical fault on AMPS.
View SEL relay data to see results.
Test Plan for the FVSCS
NOTE: Make a copy of this test plan, record the results, and keep for records
Instructions: When a value needs to be checked, record your results in the Record
column in the space provided.
Steps to perform
Turn off AMPS
 Verify that the AMPS is off and that all line circuit breakers are open.
Record
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Test the power strip
 Unplug all devices from the power strip.
 Plug the power strip into a wall outlet.
 Turn on the power strip.
 Verify that the power strip is reset and on (check switch on the power strip).
 Turn off the power strip.
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Test the Converter Fans
 Plug the converter fan power supply into the power strip.
 Turn on the power strip.
 Verify that both converter fans are running.
 Turn off the power strip.
 Verify that both converter fans stop running.
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Test 1st contacts on timing relay R1
 Plug both DC charging power supplies into the power strip.
 Verify that timing relay R1 is set to 10 seconds.
 Verify that timing relay R2 is set to 1 second.
 Place a VOM across the contacts of timing relay R1 1 and 3 and verify 0 volts.
 Turn on the power strip.
 Verify that the VOM reads greater than 0 volts and goes to 0 volts after
10 seconds.
 Turn off the power strip.
 Place shorting bars across the banana jacks to discharge the DC link capacitors.
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Test 2nd contacts on timing relay R1
 Place a VOM across the timing relay R1 contacts 6 and 8 and verify 0 volts.
 Turn on the power strip.
 Verify that the VOM reads greater than 0 volts and goes to 0 volts after 10
seconds.
 Turn off the power strip.
 Place shorting bars across the banana jacks to discharge the DC link capacitors.
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Test 1st contacts on timing relay R2
 Place a VOM across the timing relay R2 contacts 1 and 3 and verify 0 volts.
 Turn on the power strip.
 Verify that the VOM reads greater than 0 volts and goes to 0 volts after 15
seconds.
 Turn off the power strip.
 Place shorting bars across the banana jacks to discharge the DC link capacitors.
Test 2nd contacts on timing relay R2
 Place a VOM across the timing relay R2 contacts 6 and 8 and verify 0 volts.
 Turn on the power strip.
 Verify that the VOM reads greater than 0 volts and goes to 0 volts after 15
seconds.
Test DC bus voltages
 Verify that capacitor 1 has approximately 225 volts across it.
 Verify that capacitor 2 has approximately 225 volts across it.
 Verify that the DC bus has approximately 450 volts across it.
 Turn off the power strip.
 Unplug relay R2.
 Place shorting bars across the banana jacks to discharge the DC link capacitors.
Test STPWM converter
 Disconnect converter 1 from the DC bus.
 Turn on the power strip.
 Set a function generator to generate 250mHz square wave with a magnitude of 3.3
volts.
 Connect an oscilloscope to the outputs of the IGBTs and to the function generator.
 Connect the function generator to the sag bit of the converter 2.
 Verify that when the function generator is high, the IGBTs output is in the form of
a STPWM signal.
 Verify that when the function generator is low, the IGBTs have no output.
 Disconnect the function generator and oscilloscope from the converter 2.
 Turn off the power strip.
 Place shorting bars across the banana jacks to discharge the DC link capacitors.
 Reconnect converter 1 to the DC bus.
Test SVPWM converter
 Disconnect converter 2 from the DC bus.
 Turn on the power strip.
 Set a function generator to generate 250mHz square wave with a magnitude of 3.3
volts.
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 Connect an oscilloscope to the outputs of the IGBTs and to the function generator.
 Connect the function generator to the sag bit of the converter 1.
 Verify that when the function generator is low, the IGBTs output is in the form of
a SVPWM signal.
 Verify that when the function generator is high, the IGBTs have no output.
 Disconnect the function generator and oscilloscope from the converter 1.
 Turn off the power strip.
 Reconnect converter 2 to the DC bus.
 Place shorting bars across the banana jacks to discharge the DC link capacitors.
 Replace relay R2.
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Connect together all components of the FVSCS
 Connect the circuit as shown in the connection diagram.
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Turn on AMPS
 Start up the AMPS system (leaving all line circuit breakers open at this time).
 Set up the fault matrix for a high impedance 3 phase symmetrical fault of 1.5
seconds max (but do not initiate the fault at this time).
 Close the circuit breaker on the line that the FVSCS is connected to.
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Test FVSCS specifications
 Turn on the power strip.
 Verify that after 30 seconds that the DC bus has 450 volts on it.
 Verify that the flywheel is spinning at 1755 RPM with a strobe.
 Connect an oscilloscope to the sag bit line of the boards.
 Verify that the sag bit is in the low (0V) state.
 Initiate the 3 phase symmetrical fault on the line.
 Verify that the sag bit goes high (3.3V) state.
 Check SEL relay data to verify that the fault was corrected.
-  For the full duration of the sag.
-  To within 0.95  0.05 p.u. of nominal voltage.
-  Correction occurring within two cycles
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