POWER SEMICONDUCTOR SYSTEMS II Author: Ales Havel Phone number: 4287 Headquarters: E227 Web page:

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 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 V2Switching off switches V1 and V2 Current commutation in the loadConducting time of switches V3 and V4 CC = commutation circuit

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:

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