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DEMO TITLES
4 staggered converters draw 24-pulse current Case I: Converters
feed RL loads
Case II: Converters feed H Bridges (DC motors drive)
Author: Tshibain Tshibungu Simsmart Technologies Inc.
Brossard, Quebec Canada
Software used: Simsmart Engineering Suite V6 (ES V6)
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1. OBJECTIVE AND DESCRIPTION
The following test cases are done in order to test and validate
the power electronics components from the Engineering suite V6
Electrical library and analog components.
Case I: 4 staggered converters draw 24-pulse current feeding RL
loads Four separate 6-pulse converters combine to draw a 24-pulse
current from the power system. All converters feed identical RL
loads.
Case II: 4 staggered converters draw 24-pulse current feeding H
bridges that drive DC motors
Four separate 6-pulse converters combine to draw a 24-pulse
current from the power system. All converters feed identical H
bridges that drive 4-quadrant DC motors.
2. PROCESSES DATA
1. 4 staggered converters draw 24-pulse current (RL loads)
Source voltage (sine wave) and diode with snubber
Transformer Yy 0 degree
Phase shifting transformers (Zny 7.5 deg, Zny -22.5 deg, Zny
-7.5 deg, Zny -37.5 deg)
Loads
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2. 4 staggered converters draw 24-pulse current (DC motors)
Source voltage (sine wave) and diode with snubber
Transformer Yy 0 degree
Phase shifting transformers (Zny 7.5 deg, Zny -22.5 deg, Zny
-7.5 deg, Zny -37.5 deg)
DC motors
Maximum current and smoothing inductor are respectively 20 A and
10 mH
The speed PI controller
( )
Hysteresis current control: 2 A
IGBT without snubber
The load torque is proportional to motor speed:
Reference speed: Initially 1000 rpm (104.72 rad/s), at 0.8 s set
to -1000 rpm (-104.72 rad/s)
3. SIMULATION PARAMETERS
The simulation was run in time domain with sample time of
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4. PROCESSES REPRESENTATION IN ES V6
4 staggered converters draw 24-pulse current (RL loads)
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4 staggered converters draw 24-pulse current (DC motors)
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6. ENGINEERING SUITE V6 RESULTS
4 staggered converters draw 24-pulse current (RL loads)
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NETWORK CURRENT FOURIER ANALYSIS
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4 staggered converters draw 24-pulse current (DC motors)
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NETWORK CURRENT FOURIER ANALYSIS
Conclusion
The following conclusions can be made:
the network current in steady state contains less harmonics (2.5
%) as displayed above.
the inrush current (network) is due to the capacitor charging.
One can avoid that by using a precharged capacitor or another
circuit to precharge.
the motors current dont exceed the maximum allowed (20 A).
7. REFERENCE BOOKS
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1. Power electronics. Converters, applications and design, 2nd
edition. Mohan / Underland / Robbins.
2. Power electronics. Converter Harmonics. Multipulse methods
for clean power. Derek A. Paice
3. Electric Motor Drives. Modeling, Analysis, and Control. R.
Krishnan.
