电工技术学报2025，Vol.40Issue(6)：1864-1877,14.DOI:10.19595/j.cnki.1000-6753.tces.240462
半波整形模块化多电平换流器动态建模及多目标控制策略
Dynamic Model and Multi-Objective Control Strategy of Half-Wave Shaping Based Modular Multilevel Converter
摘要
Abstract
The traditional modular multilevel converter(MMC)has drawbacks such as many submodules,large volume and weight,and high cost.The lightweight MMC topologies have become a research hotspot.Half-Wave Shaping MMC(HWS-MMC)is a new lightweight hybrid multilevel converter that integrates the merits of the two-level topology and the MMC topology.The HWS-MMC can reduce the module numbers and voltage stress since the multilevel arm only needs to modulate part of the sinusoidal waveform.In existing studies,phase-shift modulation and third-order harmonic injection methods for energy balance issues of the wide-range operation of HWS-MMC are based on the inverter operation with supply ideal DC voltages supply,and no detailed multi-objective control design has been conducted.Therefore,this paper studies the dynamic model and multi-objective control strategy of HWS-MMC. Firstly,the topology and working principle of HWS-MMC are introduced,and the energy balance mechanism and phase-shift wide-range modulation method are clarified by deriving the arm energy accumulation expression.The mathematical models of internal and external variables are established for HWS-MMC,including grid current dynamics,submodule capacitor voltages,and DC bus capacitor voltage.Then,a fully averaged dynamic model without switching characteristics is obtained and linearized using the multi-scale switching period averaging technique.An overall control strategy is systematically established with the objectives of grid current control,two-stage DC voltage control,and energy balancing control between phases and within an arm.The design method of the multi-loop controllers and commutation control logic are also given. An HWS-MMC system is built on the RT-Lab platform.Experiments are conducted under the grid voltage disturbance,load disturbance,and reactive power regulations.The waveforms,including the AC voltage and current,the DC bus and submodule capacitor voltages,the modulation coefficient and phase-shift angle,and the active and reactive power,are given.The results show that the modulation coefficient and phase-shift angle are adjusted accordingly through the multi-loop control,ensuring the stability of the DC bus voltage and the submodule capacitor voltages.In addition,voltage balancing between and within phases is achieved.The half-sinusoidal multilevel waveform and six-pulsation DC bus current are consistent with the theoretical analysis. The following conclusions can be drawn.(1)The AC side characteristics of HWS-MMC are similar to traditional VSC,the characteristics of the internal module capacitors are similar to MMC,and the DC bus characteristics are similar to the six-pulsation rectifier.(2)The dynamics of the DC bus capacitor voltage and submodule capacitor voltage are independent.(3)The multi-control objectives are achieved with additional phase-shifting control and the submodule modulating wave correction.关键词
半波整形模块化多电平换流器/动态模型/能量平衡/电压均衡/多目标控制Key words
Half-wave shaping based modular multilevel converter(MMC)/dynamic model/energy balancing/voltage balancing/multi-objective control分类
信息技术与安全科学引用本文复制引用
孙玉巍,陶聪,付超,张泽霖,王琛,王毅..半波整形模块化多电平换流器动态建模及多目标控制策略[J].电工技术学报,2025,40(6):1864-1877,14.基金项目
国家自然科学基金(52077079)和中央高校基本科研业务费专项资金(2022MS072)资助项目. （52077079）
