Gate drive device

A gate drive device configured to drive a gate of a semiconductor switching element constituting an upper or lower arm of a half bridge circuit which supplies an output current, which is alternating current, to a load, the gate drive device comprising:

• a voltage detection unit configured to detect a peak value of an element voltage which is a voltage of a main terminal of the semiconductor switching element or a change rate of the element voltage when the semiconductor switching element is switching;
• a maximum value acquisition unit configured to acquire and output a maximum value among a plurality of peak values or a plurality of change rates detected by the voltage detection unit during a predetermined detection period including a period in which the semiconductor switching element performs switching multiple number of times;
• a calculation unit configured to calculate a value of a gate resistance or a gate current of the semiconductor switching element such that a deviation between the maximum value output from the maximum value acquisition unit and a target value of the peak value or a target value of the change rate determined according to a specification of the semiconductor switching element becomes small;
• and
• a drive unit configured to change the value of the gate resistance or the gate current of the semiconductor switching element based on a calculation result by the calculation unit, and drive the gate of the semiconductor switching element.