By combining the advantages of line commutated converter (LCC) and voltage source converter (VSC)

the hybrid high voltage direct current (HVDC) transmission system has extensive application prospects. Based on the hybrid HVDC transmission system

whose rectifier is LCC and inverter is VSC

the characteristics and application fields of monopole

pseudo-bipole and bipole hybrid structures are described. In consideration of the main circuit system parameters and control parameters having direct influence on the system operation performance

a novel method of synchronously optimizing the main circuit system parameters and control parameters is proposed. Firstly

the parameters design principle of smooth reactor L and capacitor C at direct current side is presented

then the LC parameters and proportional-integral control parameters are optimized based on the Simplex algorithm. A hybrid HVDC transmission model is developed in PSCAD/EMTDC

the simulation results showing that its operation performance is improved with optimized parameters

proof of the effectiveness of the proposed optimized method. This work is supported by National Natural Science Foundation of China (No. 51177042) and Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP) of China (No. 20130036120006).