Focusing on the passive network, this paper analyzes

the discrete mathematical model and its control strategy of the

passive terminal of the VSC-HVDC system on the basis of the α-β

frame of axes. The method of the functioning-fuzzy-subset

inference is introduced into automatic regulation of the

proportional integral (PI) parameters. Based on the digital signal

processor (DSP), the fuzzy PI control method is adopted and the

VSC-HVDC experiment device is constructed. The experiment of

constant AC voltage control based on fuzzy adaptive PI controller

in transmitting power to passive network via VSC-HVDC system

is developed.