IGBT Modules - Technologies, Driver and Application (Second Edition) - page 424

There are differences regarding the requirements for the IGBT modules for the main
inverters and theauxiliary inverters. For themain inverter:
High thermal cycling capability, which generally require modules with AlSiC
baseplates or designs of comparable performance. Lifetimes of up to 30 years
need to be served.
Depending on the topology, i.e. two-level or three-level inverters, modules with
a voltage rating of 1.7kV up to 6.5kV are in use. There are more stringent
standards regarding the insulation requirements than apply to standard
industrial applications.
The requirements for the auxiliary converters, however, are more relaxed because the
design concept uses is either redundancy or will cause no significant disruptions in
operation if they fail, so that the general requirements are similar to those of standard
industry requirements. However, the relevant standards for traction applicationsmust be
adhered to (e.g. IEC 601287-1andEN 50124).
11.6.6Switched reluctancemotor
Any of the basic circuits already discussed would commonly be used to control the
motors. The following table contains a list of common motors with their typical power
electronic drive circuits. The control of the switched reluctance motor (SRM) will be
Power unit
VSI, CSI, MatrixConverter
VSI, CSI, MatrixConverter
Classical Converter
Tab. 11.3
Overviewof selectedmotors and their driveunits
An SRM has salient poles both on the stator as well as on the rotor. Coils aremounted
on the poles of the stator. The coils or phases are controlled by the inverter one by one.
When current is supplied to a phase it attracts the nearest pole of the rotor until the
poles of the stator and the rotor face each other. Then, the next phase is activated and
the process repeats itself. This causes a continuous movement of the rotor. SRM are
available in different versionswith one to several phases. Each phase can be controlled
by a non-reversing current. Each phase has a half-bridge circuit as shown
(here, a total of three half-bridges for the three phases shown). This configuration is also
known as classical or asymmetrical half-bridge converter.
The individual switching states of a classical converter for an SRM are illustrated i
After switching on T
and T
, a current flows through the phase winding and
builds up a magnetic field. In the next step T
is switched off and the current flows
through the freewheeling path of D
and T
. To let themagnetic field decay both T
are turned off and the current can decay via the diodes D
and D
. The switching
frequency of the classical converter corresponds to the output frequency, i.e. at low
speeds, the switching frequency is also low. This has implications for the driver stage,
especially if a bootstrap power supply circuit is intended (chapter
. Possibly, at
high bias currents of the driver transistors, a discharge of the bootstrap capacitor can
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