铁路功率调节器的稳定性及其控制策略研究

Research on Stability and Control Strategy of Railway Power Conditioner

电气化铁路功率调节器为大功率并网系统,开关频率比较低,单电感L型滤波器输出效果不是很理想,通常采用LCL滤波器,但又提高了系统阶数,影响系统稳定性。为此,对其稳定性及控制策略进行了研究,并提出一种新的控制策略。首先建立了基于LCL滤波器的铁路功率调节器数学模型,并对数学模型特征方程与电流反馈选择等稳定性进行了分析。其次,针对传统PI调节器比例参数取值范围窄、稳定裕度低,不能有效抑制谐振的缺点,提出了准谐振控制器策略。最后,通过仿真与实验验证了理论分析及算法的正确性。

Because railway power conditioner is a large power grid system, which switching frequency is relatively low, and output effect of single inductance type L filter is not very ideal. Usually LCL filter is adopted, but it increases system order, adversely affecting system stability. This paper focuses on the stability and proposes a new control strategy. Firstly, mathematical model of railway power regulator based on LCL filter is established, and the stability of characteristic equation and current feedback selection of the mathematical model are studied. Secondly, a quasi-resonant controller strategy is proposed, aiming at the shortcoming of traditional PI regulator that range of parameters is narrow, stability margin is low, and system resonance caused by LCL filter cannot be effectively suppressed. Finally, correctness of theoretical analysis and the algorithm is verified with simulation and experiment.