全桥型MMC数字-物理混合仿真阻尼阻抗接口模型

数字-物理混合仿真结合了数字仿真与物理实验的优势,为复杂电力电子设备的理论研究和工程设计过程提供了便利。然而数字-物理接口的存在可能导致数字-物理混合仿真结果精度降低甚至变得不稳定。为解决数字-物理接口引起的失稳问题,文中在传统阻尼阻抗接口模型的基础上,针对应用于柔性直流输电的全桥型模块化多电平换流器(MMC),提出一种接口补偿阻抗设计方法。首先,全面充分地考虑了接口引入的延时、扰动对系统稳定性和精确性的影响,根据MMC的运行特点,设计了结构简单的RLC串联结构补偿阻抗,使之在不同运行工况下均可确保系统稳定、高精度运行。在此基础上,搭建了基于全桥型MMC直流背靠背的数字-物理混合仿真实验平台,利用数字侧模拟电压暂降、短路等故障,而物理侧全桥型MMC实现故障穿越过程。实验结果表明,所提接口补偿阻抗设计方案保证了系统在各种工况下的有效性。

Damping Impedance Interface Model of Power Hardware-in-the-loop Simulation for Full-bridge Modular Multilevel Converter

Power hardware-in-the-loop (PHIL) simulation combines the advantages of digital simulation and physical experiment, which brings convenience to the theoretical research and engineering design of complex power electronic equipment. However, the existence of the digital-physical interface may cause low precision of PHIL simulation and even lead to instability. In order to solve the problem, based on the traditional damping impedance interface model, this paper proposes a design method of interface compensation impedance for the full-bridge modular multilevel converter (MMC) applied to the flexible DC transmission. Firstly, the effects of the delay introduced by interface and the disturbance on system stability and accuracy are comprehensively considered. According to the operation characteristics of MMC, a simple structure of series RLC compensation impedance is designed, which can guarantee system stability and high accuracy under different operation conditions. Furthermore, an experimental platform of DC back-to-back PHIL simulation based on full-bridge MMC is built, and the voltage drop, short-circuit faults,etc. are simulated in the digital side while the fault ride-through process of a full-bridge MMC is realized in the physical side. The experimental results show that the proposed design method of interface compensation impedance guarantees the system effectiveness under various operation conditions.