After bipolar block in high voltage direct circuit (HVDC) transmission system, a large amount of reactive power flows to the AC bus at the sending end due to the lag exit of the rectifier station filter and compensation devices, which leads to the phenomenon of overvoltage at the sending end. A nonlinear robust control strategy based on state-dependent Riccati equation technique is proposed to ensure safe operation of large-scale DC near-field photovoltaic generation system. Firstly, the transient control goal is set to maximize the absorbed reactive power of the photovoltaic generation system during the transient period, and the appropriate adjustment output is selected based on the control goal and the corresponding nonlinear robust control problem is constructed. Secondly, the state-dependent Riccati equation technique is used to transform the nonlinear robust control problem into the state-dependent linear-like system robust control problem, and the state feedback control law is approximately obtained by the online solution of the algebraic Riccati inequality. Finally, the simulation results of MATLAB/Simulink show that the proposed control strategy has good transient control effect and can effectively suppress the overvoltage at the sending end.