IGCT converter valve turn-off control method based on current change rate detection

The invention provides an IGCT converter valve turn-off control method based on current change rate detection, and the method comprises the steps: receiving a converter valve side line voltage phase angle and a trigger instruction angle given by upper control, inputting a trigger instruction to an IGCT when the valve side line voltage phase angle is greater than the trigger instruction angle, and conducting a converter valve; detecting the change rate of the valve current of the converter valve along with time; after a phase-change valve corresponding to the converter valve is conducted, a maximum phase-change angle is set; and in the maximum commutation angle time, when the current of the converter valve is reduced, the time change rate is approximate to zero, and the current of the converter valve meets the device turn-off capability limitation, inputting a turn-off instruction to the IGCT, and turning off the converter valve. The method can effectively solve the problem of commutation failure of a conventi