Trigger phase control is the basis for the control of high voltage direct current(HVDC)system. The effect of trigger phase control on the performance of HVDC is very obvious under asymmetric fault conditions. Aiming at the poor anti-interference of zero-crossing detection of traditional individual phase control and the low degree of control freedom for equidistant firing control

an individual phase control scheme based on single-phase locked loop is proposed. The phase-locked process of the proposed method has strong ability of suppressing harmonics and negative sequence voltage interference

and can obtain more detailed voltage phase information under asymmetrical conditions which reduces the difference of actual trigger angle of each valve. Finally

the stability of HVDC and transient performance under the condition of proposed method are tested and analyzed with PSCAD/EMTDC. The simulation results show that the new individual phase control has no adverse effect on the stability of HVDC

and effectively reduces the probability of commutation failure during AC fault recovery

which verifies the superiority of the proposed method.