Patent ID: 8050064

Claim:
A semiconductor power conversion device converting a variably controlled main circuit power supply voltage, comprising: a semiconductor switching element controlling a current between first and second electrodes in response to a voltage or current of a control electrode; a drive control unit for setting a control voltage within a range from a first voltage for rendering said semiconductor switching element conducting to a second voltage for disconnecting said semiconductor switching element, in accordance with a control signal indicating turn-on and turn-off of said semiconductor switching element; and a drive circuit for driving said voltage or current of said control electrode in accordance with said control voltage set by said drive control unit, said drive control unit including a voltage detection unit for detecting an inter-electrode voltage across said first and second electrodes, a surge control target setting unit for variably setting in accordance with said main circuit power supply voltage, a control target of a surge voltage generated across said first and second electrodes when said semiconductor switching element is turned off, and a first active gate control unit for modifying said control voltage toward said first voltage by a quantity of voltage modification based on said inter-electrode voltage, when said inter-electrode voltage detected by said voltage detection unit exceeds said control target.