Page 179 - Power Electronic Control in Electrical Systems

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Power electronic control in electrical systems 167

Fig. 5.12 Converter power level and frequency for various semiconductor devices.
operate at relatively higher frequencies, and finally the MOSFET extends its opera-
tion to high frequency regions for relatively low power levels. The tendency over the
next few years is to have the GTO extend its power area towards the thyristor level.
At the same time, the IGBT will also extend its power ability towards the GTO with
higher switching frequency.

5.3 Power modules

Manufacturers of high power semiconductor devices offer power modules, which are
easy to use to build a power electronics converter. Power modules offer two or more
devices typically of the same type interconnected in a certain way to facilitate build-
ing a given converter topology. The power modules also naturally have increased
voltage and/or current ratings due to internal series and/or parallel connection of
several semiconductors. Converter legs for a single-phase and three-phase converter
are also available and in many cases a modular converter including not only the
three-phase inverter legs, but also the front-end three-phase diode rectifier and other
integrated components.

5.4 Passive components

Many other components must be used to make a converter topology function
properly to shape the voltage and current supplied from the source to the ones
required by the load in a regulated manner and in many cases allow the power flow