Abstract: In a power conversion apparatus, a main switching element in one main circuit is controlled to repeat an on-off state, and a diode in the other main circuit is used as a freewheeling diode. Multiple snubber circuits each having a resistor, a capacitor, and a second switching element which are serially coupled are coupled in parallel to the main circuit. The second switching elements are turned-on sequentially before the turn-on or turn-off of the main switching element that repeats the on-off state.

Abstract: In a power conversion apparatus, a main switching element in one main circuit is controlled to repeat an on-off state, and a diode in the other main circuit is used as a freewheeling diode. Multiple snubber circuits each having a resistor, a capacitor, and a second switching element which are serially coupled are coupled in parallel to the main circuit. The second switching elements are turned-on sequentially before the turn-on or turn-off of the main switching element that repeats the on-off state.

Abstract: An IGBT drive circuit is provided with a series regulator and a drive circuit. The series regulator includes a transistor and a control circuit. The control circuit and the drive circuit are integrated as an IC. The transistor is connected to the IC as an external component. Since the control circuit and the drive circuit are integrated, the number of components necessary for the IGBT drive circuit can be reduced. Further, the transistor is excluded from the IC so that radiant heat by the IC can be suppressed whereby an IC package having high heat-radiation characteristics is not necessarily used so that increasing size of the IC is avoided.