混合型MMC的改进桥臂平均值与状态空间模型  

Improved Arm Average and State-space Models of Hybrid Modular Multilevel Converter

作　　者：郭猛 郝全睿[1] 李东[1] GUO Meng;HAO Quanrui;LI Dong(Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education(Shandong University),Jinan 250061,China)

机构地区：[1]电网智能化调度与控制教育部重点实验室(山东大学),山东省济南市250061

出　　处：《电力系统自动化》2023年第19期116-127,共12页Automation of Electric Power Systems

基　　金：国家电网有限公司总部科技项目(送端大规模新能源经柔直送出孤岛系统协同控制关键技术研究,5108-202299261A-1-0-ZB)。

摘　　要：混合型模块化多电平换流器(MMC)包含半桥与全桥子模块是MMC的通用形式。混合型MMC的常规桥臂平均值模型将半桥与全桥子模块动态视为一致,未考虑两者电容电压可能存在的差异,不能精确描述混合型MMC的动态特性。文中首先考虑半桥与全桥子模块动态特性差异,构建等效电路;其次,提出模拟桥臂调制信号在全桥与半桥子模块间非线性分配的算法,与等效电路共同组成混合型MMC改进桥臂平均值模型。在此基础上,考虑半桥与全桥子模块电气量高次谐波,推导混合型MMC电气部分在dq同步坐标系下的微分动态方程;基于桥臂参考电压非线性分配算法和分段求解方法,推导半桥和全桥子模块等效参考电压解析表达式;建立混合型MMC在dq同步坐标系中的模块化状态空间模型。最后,以测试系统为例,在PSCAD和Simulink中对比详细开关模型与所提模型的暂稳态波形,验证了所提建模方法的有效性和准确性。The hybrid modular multilevel converter(MMC)is the general form of MMC,which consists of the half-bridge submodule(HBSM)and the full-bridge sub-module(FBSM).The conventional arm average model(AAVM)of hybrid MMC regards the dynamics of HBSM and FBSM as the same,which does not take into account the difference in capacitor voltage between the two sub-modules.So,it cannot describe the dynamics of hybrid MMC accurately.Firstly,considering the difference in dynamic characteristics between HBSM and FBSM,this paper constructs the equivalent circuit.Secondly,an algorithm that simulates the nonlinear distribution of the arm modulation signal between HBSM and FBSM is proposed.The equivalent circuit and the algorithm constitute the improved AAVM of hybrid MMC.On this basis,considering the high-order harmonics of the electrical variables of HBSM and FBSM,the differential dynamic equation of the electrical part of the hybrid MMC in the dq synchronous coordinate system is derived.Based on the nonlinear distribution algorithm of the arm voltage reference and the piecewise solution method,the analytical expressions of equivalent voltage references of HBSM and FBSM are derived.A modular state-space model of hybrid MMC in the dq synchronous coordinate system is established.Finally,taking the test system as an example,the transient and steady-state waveforms of the detailed switching model and the proposed model are compared in PSCAD and Simulink to verify the effectiveness and correctness of the proposed modeling method.

关 键 词：柔性直流输电 模块化多电平换流器 平均值模型 等效电路 非线性分配 状态空间模型 

分 类 号：TM721.1[电气工程—电力系统及自动化] TM46