基于自适应模式切换的MMC-HVDC数字物理混合仿真新型接口算法

A Novel Interface Algorithm of Power Hardware-in-the-loop Simulation for MMC-HVDC System Based on Adaptive Mode Switching

数字物理混合仿真已成为模块化多电平换流器柔性直流输电技术(modular multilevel converter based high voltage direct current,MMC-HVDC)的重要研究手段,而接口算法是保证其系统稳定性和仿真精确性的关键技术。基于理想变压器模型法与阻尼阻抗法接口特性的对比分析,提出了一种基于自适应模式切换的新型接口算法,可在保证MMC-HVDC数字物理混合仿真系统稳定性的同时提高仿真精度。针对阻尼阻抗法,提出了物理动模交流场等效阻抗的精确计算方法,并简化了MMC交流侧等效阻抗的计算过程,实现了阻抗的实时匹配;根据2种接口算法的结构原理,在阻尼阻抗法的附加阻抗支路增加了一个可控开关,并以理想变压器模型法接口稳定性为依据设计了开关的动作条件及其误动的解决方案,进而设计新型接口算法的实现流程,保证接口特性的有效切换。通过数字仿真对比分析了新型接口算法与常用接口算法的接口特性,验证了其优越的稳定性和精确性。最后,设计了适用于MMC-HVDC数字物理混合仿真平台的启动方案,并通过硬件在环实验验证了所提方法的有效性和可行性。

Power hardware-in-loop(PHIL)simulation has become an important research measure of modular multilevel converter based high voltage direct current(MMC-HVDC)technology,and interface algorithm is the key technology to ensure system stability and simulation accuracy.Based on comparative analysis of the interface characteristics between ideal transformer model(ITM)method and damping impedance method(DIM),a novel interface algorithm based on adaptive mode switching is proposed to improve simulation accuracy while guaranteeing stability of MMC-HVDC PHIL simulation system.For the DIM,an accurate calculation method for the AC field equivalent impedance of the hardware under test(HUT)is proposed,and the calculation process of the equivalent impedance for MMC AC side is simplified to realize real-time impedance matching.According to the structure principle of the two interface algorithms,a controllable switch is added to the additional impedance branch of the DIM,and the switching conditions of the switch and the solution of maloperation are designed based on interface stability of the ITM.Then,an implementation process of the novel interface algorithm is designed to ensure effective switching of the interface characteristics.The interface characteristics of the novel and common interface algorithms are compared and analyzed with digital simulation,and its superior stability and accuracy performance are verified.Finally,a start-up scheme for the MMC-HVDC PHIL simulation platform is designed,and effectiveness and feasibility of the proposed method are verified with hardware-in-loop experiments.