Semiconductor power conversion apparatus

DETAILED DESCRIPTION It is therefore an object of the present invention to provide a semiconductor power conversion apparatus which suppresses a steep rise of the IGBT collector voltage to protect the IGBT against overvoltages, and which has means for preventing the collector voltage from being clamped excessively when the voltage rising rate (dv/dt) of the collector voltage becomes large and thereby preventing an increase in the turn-off loss.
To solve the problems described above requires fixing the case of the high-voltage side resistor to the emitter potential of the IGBT.
That is, in one aspect, the present invention provides the semiconductor power conversion apparatus which comprises: a circuit for diving a collector voltage of an IGBT; and means for controlling a gate potential of the IGBT to a potential of a voltage dividing point in the collector voltage dividing circuit to protect the IGBT against an overvoltage applied to a collector of the IGBT; wherein a voltage of a case of a resistor on a high-voltage side of the voltage dividing point is fixed to an emitter potential of the IGBT, and a plurality of the IGBTs connected in series are switched simultaneously.
In another aspect, the present invention provides a semiconductor power conversion apparatus wherein the IGBT collector voltage dividing circuit has a high-voltage side resistor and a low-voltage side resistor, and wherein a sum of terminal-to-terminal resistances of the high-voltage side resistor and the low-voltage side resistor divided by the resistance of the low-voltage side resistor is equal to an impedance produced by a stray capacitance between the terminals of the high-voltage side resistor divided by an impedance produced by a stray capacitance between a high-voltage side terminal of the high-voltage side resistor and the case of the high-voltage side resistor.
As described earlier, in wire wound resistors such as those shown in FIG.
4 and in resistors having conductive particles scattered in an inorganic material as shown in FIG