PROTECTION CIRCUIT FOR SEMICONDUCTOR SWITCHING ELEMENT, AND POWER CONVERSION DEVICE

摘要

Upon turn-off of IGBT, by suppressing variations in collector-emitter voltage between IGBTs connected in series, risk of breaking IGBT due to overvoltage breakdown can be reduced. In protection circuit provided for each of the plurality of IGBTs 50 connected in series, between collector and emitter of IGBT 50, avalanche elements D1˜D5, resistance R4 and avalanche element D6 are sequentially connected in series. Capacitor C1 and resistance R1 are connected parallel between both ends of the avalanche element D4, and capacitor C2 and resistance R2 are connected parallel between both ends of the avalanche element D5. Between a common connection point of the resistance R4 and the avalanche element D6 and gate of the IGBT 50, resistance R5, a parallel circuit of capacitor C3 and resistance R6, and a series component of Zener diodes ZD1 and ZD2 whose polarities are opposite to each other, are connected in series.

主权项

1. A protection circuit provided for each of a plurality of semiconductor switching elements connected in series, comprising:
a first protection circuit configured so that a cathode of a first avalanche element is connected to a collector of the semiconductor switching element, an anode of the first avalanche element is connected to a cathode of a second avalanche element, a first capacitor and a first resistance are connected parallel to the second avalanche element, and an anode of the second avalanche element is connected to one end of a second resistance; and a second protection circuit configured so that a cathode of a third avalanche element is connected to the other end of the second resistance, an anode of the third avalanche element is connected to an emitter of the semiconductor switching element, one end of a series component of third and fourth resistances is connected to a common connection point of the second resistance and the third avalanche element, and first and second Zener diodes are connected in series with their polarities being opposite to each other between the other end of the series component of third and fourth resistances and a gate of the semiconductor switching element.