To address the issue in high voltage direct current (HVDC) systems where the fixed extinction angle control strategy on the inverter side fails to consider changes in the extinction voltage-time area, which can easily lead to commutation failure due to incomplete extinction of the converter valves, an improved fixed extinction angle control strategy with self-adaptive regulation of the extinction angle is proposed. This control strategy takes into account the variations in both the commutation area and the extinction area. By dynamically adjusting the extinction angle, it ensures sufficient time margin for the extinction process and predicts current changes based on the characteristics of sudden changes in DC current, enabling early triggering to prevent commutation failure. Simulation tests conducted using PSCAD/EMTDC software demonstrate that compared to the original fixed extinction angle control strategy, the improved strategy better withstands commutation failures caused by short-circuit faults on the inverter-side AC system, while also improving the fault recovery characteristics of the DC system and reducing the sustained impact of short-circuit faults on the system.