To realize the long-distance and high-efficiency transmission of water and wind clean energy

this paper proposes a controllable voltage source-current source hybrid bipolar UHVDC transmission scheme for large-scale clean energy delivery. The paper establishes a quasi-steady state model of the controlled voltage source-current source hybrid DC system

and analyzes the operation mode and the power operation characteristics of the AC/DC system after large-scale clean energy integration. In addition

a closed-loop control strategy is proposed in this paper

which can effectively track the given reference value of the voltage signal from the capacitor and realize the unit power factor operation. Based on the established mathematical model

to optimize the fast tracking of the capacitor voltage controller

a controlled current source converter controller is designedso that the system parameters can meet the design requirements. Finally

a controllable voltage source-current source hybrid UHVDC system is constructed

and simulation analysis is carried out to verify the operation characteristics and control strategy of the system under the transient and steady-state condition

focusing on the startup process of the system

rated operation

and the dynamic response characteristics under the improved controller parameters.