Reduced-order model of HVDC Light System based on multi-time scale

HVDC Light is a new generation of HVDC power transmission based on PWM controlled voltage source converter(VSC). First, this paper presents an equivalent statespace model of HVDC Light system under dq synchronous rotating coordinate system. After established the detailed model, the simplified model based on the multi-time scale theory was given. The HVDC Light mathematical model is decomposed into the slow and fast subsystems in explicit form. By applying state-feedback, output feedback control strategy based on multi-time scale model is proposed. In the end, the coherency between the reduced and composite models is compared by MATLAB simulation, and the simulation result assures that the simplified model based on multi-time scale is valid to design state-feedback controller.