Design and simulation of VSC-HVDC controller

VSC-HVDC composed by full-controlled converter units is more flexible transmission schemes compared with traditional HVDC. It is necessary to study its control mode. This paper first analyzes the steady-state model of VSC-HVDC, then obtains the relationship among modulation wave phase δ, modulation degree m, active power and reactive power. When it is connected with active network VSC-HVDC can be deduced to a two-input and two-output circuit. With the characteristics the PI controller with inertial integral element is designed to achieve the independent control of active and reactive power. Simulation based on PSCAD / EMTDC demonstrates that the designed controller has good response speed and stability by modeling the mutation of active and reactive power.