HVDC Light is a new HVDC transmission system based on VSC (Voltage Source Converters) technology. The interconnected generator-network HVDC Light models are established in this paper, the models include: (1) a DC two-terminal monopolar system and (2) a parallel AC/DC power system consisting of voltage source converters. Then a new optimal controller based on the established models is proposed in this paper. The comparisons of damping performance to the power system are made between the HVDC Light with the proposed controller and the conventional HVDC, and then the improvement to the transient stability with the HVDC Light is verified by the simulation results.