Common problems and solutions in IGBT application
Author: Shenzhen Yuan Zhi Electronics Co., Ltd.Time:2018-03-01 17:15:15Views:4289【SML】
In the IGBT application, the key is over-current protection. IGBT can withstand the over-current time of only a few microseconds, which scr, gtr (tens of microseconds) and other devices is much smaller, so the over-current protection requirements even higher. igbt over-current protection can be divided into two types, ...
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In the IGBT application, the key is over-current protection. IGBT
can withstand the over-current time of only a few microseconds, which
scr, gtr (tens of microseconds) and other devices is much smaller, so
the over-current protection requirements even higher. igbt
over-current protection can be divided into two types, one is the low
multiple (1.2 to 1.5 times) of the overload current protection; the
other is a high multiple (8 to 10 times) short-circuit current
protection. For overload protection can be used instantaneous blocking gate pulse method to achieve protection. IGBT
module, IGBT module for short-circuit current protection, plus
instantaneous closure of the gate pulse will be due to short-circuit
current drop di / dt is too large, very easy to induce a high collector
voltage on the loop stray inductance Overspeed breakdown igbt, Disabling protection.
Therefore, the reliable short-circuit current protection should have the following features:
(1) Firstly, the gate voltage should be softened to limit the peak
value of short-circuit current, extend the allowable short-circuit time,
and win the time for protection action.
(2) Protection of cut-off short-circuit current should be implemented soft-off
igbt drive exb841, m57962 and hl402b can IGBT module, IGBT module applications to meet the above requirements. However,
these drives can not completely block the pulse, and if no action is
taken, the soft turn-off per cycle will be protected once the fault does
not disappear. The heat accumulation thus generated will still cause
igbt damage. To this end, the fault detection output of the driver can be used to
completely block the gate pulse through the photocoupler or to reduce
the operating frequency to less than 1hz, and automatically return to
the normal operating frequency when the fault disappears [9].
igbt
drive module m57962l comes with a protection function, the detection
circuit detects the detection of a high-voltage input pin 15v, judged as
current fault, IGBT module, IGBT module application immediately start
the door shut-off circuit, the output 5 feet Low,
so igbt deadline, while the output error signal so that the fault
output 8 feet low to drive the external protection circuit, delay 8 ~
10μs block drive signal, which can well achieve overcurrent protection. After 1 ~ 2ms delay, if the input is detected as high, then m57962l reset to the initial state.
2018-03-01
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