1. Power Semiconductor Systems II
Author: Ales Havel
Phone: 5937
Office: EA333
Web:
Power Semiconductor Systems II

2. Content of the presentation
Main types of converters
AC-DC converters
DC-DC converters
DC-AC converters
Voltage inverters
Single phase inverters
Three phase inverters
Current inverters
AC-AC converters

3. Power converters
A power semiconductor converter is an electrical device for converting electrical energy.

4. Single phase current inverters
Conducting time of switches V1 and V2
Switching off switches V1 and V2
Current commutation in the load
Conducting time of switches V3 and V4
CC = commutation circuit

5. Single phase current inverters

6. Single phase current inverters
Single phase inverter with switchable power components (IGBTs)
Advantages:
No need of using accumulation circuit with diode rectifier
Parallelly connected capacitors will take the source current in the transistor switching
times
Short switching times of used IGBT transistors and faster current commutation
Lower power losses, because the IGBTs are switched with zero voltage (ZVS)

7. Three phase current inverters
with interphase commutation
Advantages:
Most widely used variant with
commutation circuits
Commutation capacitors are separated
by isolating diodes
Voltage on the capacitors is therefore
not affected by the load
Interphase circuit provides commu-
tative and accumulative functions

8. Three phase current inverters
Three phase current inverter with switchable power parts (IGBTs)
Advantages:
By utilization of switchable power
parts is possible to reach better
quality of the output current
Capacitive character of the load
due to use of accumulation capacitors
Load capacitors are also acting as
an output filter of the inverter, so
although the phase currents are
pulse width modulated, the load
currents are almost harmonic

9. Three phase current inverters
Active and reactive power flow in current inverters
Current inverter
The average load power value is given by:

10. Thank You for your attention