IGBT OVERCURRENT AND
SHORT-CIRCUIT PROTECTION IN INDUSTRIAL DRIVES Short-circuits at
Manufacturing AtmospheresIndustrial motor
drives function at the comparatively harsh situation in which high temperature,
ac line transients, mechanical overload, and other incidents can occur. Some of
these events result in substantial overcurrent levels flowing in the motor
drive power circuits. These described below:
It causes the false turn-on of both IGBTs in one of
the inverter legs, which in turn result from electromagnetic interference malfunction in the switch. It could also cause the failure of the IGBT.
Phase to phase short-circuit.
It causes insulation breakdown at motor windings due
to degradation, over-temperature and overvoltage.
Short-circuit to earth.
It causes insulation breakdown between a motor winding
and covering; due to degradation, over-temperature and overvoltage.
capable of absorbing high current for extended periods; however, the IGBTs
majority of industrial motor drive inverter stages have short-circuited
tolerate times in microseconds. IGBT Short-Circuit
Ability The short-circuit
endure a time of an IGBT is related to its transconductance, and thermal the capacity of the IGBT die. More significant gain leads to greatershort-circuit current
levels within the IGBT, so lower-gain IGBTs willhave lower
Advances in IGBT technology resulting in the trend of
increased short-circuit current levels and subsequently reduced short-circuit withstand times.
Reducing the size and lowering thermal capacity,
which furthers the resist time. There is also a robust dependency on the collector-emitter voltage. Hence, the parallel trend toward higher dc bus voltage levels in industrial drives results in a further reduction in short-circuit resist times.
Moreover, the short-circuit withstand time widely
from to device, so it usually recommended building an additional margin
beyond the specified short-circuit face time, in IGBT protection circuits.
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Tuesday, 14th April 2020
IGBT OVERCURRENT AND SHORT-CIRCUIT PROTECTION IN INDUSTRIAL DRIVES