Patent ID: 8896365

Claim:
A semiconductor switch to be provided in a power conversion device and to be connected in series to a second semiconductor switch between a positive line and a negative line of the power conversion device, the semiconductor switch comprising: a main element including a voltage-drive-type switching element and an antiparallel diode connected in anti-parallel with the switching element; and a reverse voltage application circuit which is connected in parallel with the main element, and which includes a high-speed free wheeling diode, a capacitor, and an auxiliary element; wherein: the high-speed free wheeling diode comprises a plurality of diodes connected in series to each other, and has a reverse recovery time which is shorter than a reverse recovery time of the antiparallel diode, and a reverse recovery charge which is smaller than a reverse recovery charge of the antiparallel diode; the capacitor is connected in parallel to a power supply; the auxiliary element is turned on at a dead time set before the second semiconductor switch is turned on; and the high-speed free wheeling diode, the capacitor, and the auxiliary element are connected in series to each other.