Download 6_Current_inverters

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 converters
 AC-DC
converters
 DC-DC converters
 DC-AC converters
 Voltage


Single phase inverters
Three phase inverters
 Current


inverters
inverters
Single phase inverters
Three phase inverters
 AC-AC
converters
Power converters

A power semiconductor converter is an electrical
device for converting electrical energy.
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
Single phase current inverters
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)
Three phase current inverters
Three phase current inverter
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 commutation
and accumulation functions
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
Three phase current inverters
Active and reactive power flow in current inverters
Current inverter
The average load power value is given by:
Pd  U d  I d
Pd  0  U d  0
inverter operation mode
Pd  0  U d  0
rectifier operation mode
Thank You for your attention