Abstract:The voltage recovery of commutation bus on the rectifier side in AC/DC system always leads to the increases of DC current, thus resulting in the inverter commutation failure. In order to solve this problem, the CIGRE HVDC benchmark model is firstly taken as an example to analyze the control characteristics of control system on the inverter side during voltage recovery. The main reason of commutation failure is that the value of output current error control is small and rapidly reduces due to the large and fast increase of DC current after the control mode is switched from constant current control to constant extinction angle control. The extinction angle is small and always affected by the voltage recovery of commutation bus on the rectifier side, so that a control method is proposed to increase the extinction angle by improving the current error controller. Finally, the CIGRE HVDC benchmark model is used in PSCAD/EMTDC electromagnetic transient simulation software to verify the effectiveness of the proposed method. The simulation results show that the proposed method effectively suppresses the commutation failure caused by the voltage recovery of commutation bus on the rectifier side.