IGBT Modules - Technologies, Driver and Application (Second Edition) - page 472

Fig. 13.2
Transformer equivalent circuit
Aside from these two examples, parasitic effects exist in a multitude of inverter circuit
functions. Someof themare listed i
Inductive parasitic
(stray inductance)
Capacitive parasitic
(coupling capacitance)
Interconnection IGBTdriver
to IGBTgate
Wide track loops onPCB
Cable of output phase
(internal layout)
(activepart vs. baseplate)
Tab. 13.2
Examples of parasitic components insidean inverter
Apart from a few exceptions, one aim of the inverter design is tominimise such parasitic
effects in the best possible way. With regard to the IGBT switching behaviour, the
design of the DC-bus is of great importance and will be closely examined in the
following section.
13.5 DC-bus
The DC-bus forms the link between the inverter input and output circuit and consists of
one or several capacitors in most applications (DC-busses with inductors as energy
storage will not be detailed in this context). Such a DC-bus – with possibly high
capacitance – may not be connected to the mains without special provisions. The
charge current would be too high and detrimental in other respects. Thus, the input
rectifier or its semiconductors may be damaged by the short term current pulse. A
further effect could be a voltage overshoot at the DC-bus capacitors if the mains
impedance is unfavourable. In addition, the mains disturbance caused by the current
pulse is unacceptable and has to be reduced. A solution is, therefore, a soft-charge
circuit as described in chapte
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