DRIVE UNIT FOR SWITCHING ELEMENT

摘要

An inverter for driving a motor generator has series connection units, each of which has two switching elements, connected in series, in high and low voltage sides, respectively. A drive unit is arranged for each switching element. A gate of the switching element is connected to an emitter thereof through a first cutoff resistance and a first cutoff switching element in the drive unit. The gate of the switching element is also connected to the emitter thereof through a second cutoff resistance and a second cutoff switching element in the drive unit. A resistance value of the first cutoff resistance is higher than a resistance value of the second cutoff resistance. A software cutoff process is performed when the switching element is in a completely turned-on state so that the first cutoff switching element is turned on and the second cutoff switching element is turned off.

主权项

1. A drive unit for driving a switching element comprising:
a current detection section which detects a current flowing in an input terminal and an output terminal of a target switching element to be controlled; a turning-off section which forcedly turns off the target switching element when the current detected by the current detection section exceeds a threshold value; and a processing section which controls a switching operation performed by the turning-off section for setting the target switching element to a forcedly turned-off state so that a magnitude to suppress a surge voltage generated in a case A1 becomes larger than a magnitude to suppress a surge voltage generated in a case A2, where in the case A1, the surge voltage is generated in the target switching element when the target switching element is forcedly turned off by the turning-off section when the current detected by the current detection section exceeds the threshold value under a completely turned-on state of the target switching element; and in the case A2, a surge voltage is generated in the target switching element when the target switching element is forcedly turned off by the turning-off section under an incompletely turned-on state of the target switching element.