A passivity control strategy for VSC-HVDC connected large scale wind power

For wind farm connection VSC-HVDC transmission has obvious technical and economic advantages, but concentrated integration of large scale wind power requires stronger robustness. Based on the mathematical model of VSC-HVDC in abc frame, the Euler-Lagrange mathematical model of voltage-source-converter(VSC) in d-q rotating frame is built and the strict passivity of VSC is proved. Based on the energy dissipativity of VSC, energy storage function is established by using state error and it is used as Lyapunov function, VSC-HVDC is astringed to expected stable equilibrium point rapidly by damping addition. The passivity controller is designed according to expected equilibrium point, state variable and state error, and decoupling control for various variable is achieved. With different operation conditions, VSC-HVDC and its control system are simulated by software PSCAD/EMTDC the results show that the proposed control strategy has good performance and strong robustness either in dynamic state or steady state.