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Transcript 
Author: Ales Havel
E-mail: [email protected]
Phone number: 4287
Headquarters: E227
Web page: http://homen.vsb.cz/~hav278/
POWER SEMICONDUCTOR SYSTEMS II
Content of the presentation

Main types of frequency converters
 AC-DC
converters
 DC-DC converters
 DC-AC converters
 AC-AC converters
 Direct

frequency converters
Cycloconverters
 Indirect


frequency converters
Converters with voltage type of the DC link
Converters with current type of the DC link
Power converters

A power semiconductor converter is an electrical
device for converting electrical energy.
Cycloconverters
Characteristics:
Creation of output AC voltage without the need of DC link
Output frequency is always lower than the input frequency
Large number of thyristors (36 for 3 phase cycloconverter)
but relatively low switching power losses
Relatively complex control due to large number of switches
Non-sinusoidal consumption of mains current, therefore large
consumption of reactive power and wide spectra of harmonics
Wiring diagram
of one phase of
total three-phase
cycloconverter
Cycloconverters
Principal block wiring topologies of three-phase cycloconverters
Without common node
With common node
Cycloconverters
Utilization of cycloconverters:
Low speed three-phase synchronous motors with field windings
High power low speed drives with relatively low demands on dynamics
Principal of creation of output voltage and current
Cycloconverters – load waveforms
Output frequency: 25Hz
Load parameters: R = 7Ω, L = 10mH
Control parameters: alpha = 0°
Cycloconverters – load waveforms
Output frequency: 25Hz
Load parameters: R = 7Ω, L = 10mH
Control parameters: alpha = 30°
Cycloconverters – load waveforms
Output frequency: 25Hz
Load parameters: R = 7Ω, L = 50mH
Control parameters: alpha = 0°
Thank You for your attention
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