Research on control parameter optimization of LCC-HVDC system based on zero-pole optimal position distribution

Abstract

The proportional-integral (PI) control is widely adopted as the leading controllers of the line-commutated converter high-voltage direct current transmission system (LCC-HVDC), while unreasonable coefficients setting will result in the DC system instability and aggravate system dynamic performance. In order to improve the overall response performance of the system, a tuning method of the controller parameters guided by the linearized zero-pole transfer function of the DC system is proposed. Firstly, the small signal analysis method is used to formulate the closed-loop transfer function model at the stable operating point. According to the position of zero and pole, the objective function which can quantitatively reflect the dynamic and steady state characteristics of the DC system is derived. Furthermore, combined with the particle swarm optimization (PSO) intelligent optimization algorithm, the multi-group control parameters of the system are optimized. Finally, by comparing the time domain numerical simulation results before and after parameter optimization, it is verified that the proposed tuning method can effectively improve the dynamic and steady-state characteristics of the DC system.