摘要
基于全桥模块的模块化多电平变换器(FMMC)提出了一种单相低频(SLFAC)输电方法。一种拟方波波形作为低频侧电压波形的提出,不仅可以解除对低频侧输电频率的限制,实现1Hz甚至更低频率的输电,而且可以减小低频侧功率波动和电缆的充电电流,使SLFAC的输电能力与高压直流(HVDC)输电相近。从技术经济性角度对SLFAC,HVDC及三相低频(LFAC)输电进行对比分析。提出了适用于FMMC-SLFAC的功率平衡策略,在保证系统有功平衡的前提下,实现低频侧功率波动全部由FMMC中电容吸收,不流入工频侧。推导了由低频侧功率波动引发的电容电压波动,并在电容电压波动限幅范围内,给出了低频侧电压切换时长表达式。给出了综合控制策略,通过仿真验证了FMMC-SLFAC的有效性和可行性。
A single-phase low frequency AC（SLFAC）transmission method is proposed based on full-bridge modular multilevel converter（FMMC）.A quasi-square voltage waveform is generated for low frequency side（LFS）,which can not only lift the restriction on the frequency of LFS and realize the power transmission with the frequency of 1 Hz or even lower,but also minimize power ripple on LFS and eliminate charging currents of transmission cables.Besides,it is proved that the transmission capacity of SLFAC can be increased close to that of HVDC.Comparisons have been done among LFAC and HVDC,SLFAC in aspects of technology and economy.A power balancing strategy is proposed to adapt to the FMMC-SLFAC system.Under the premise of ensuring the balance for system active power,power ripples of LFS are absorbed by capacitors of FMMC and do not inject into power frequency side.Furthermore,the voltage ripple of capacitors caused by the power ripple of LFS is derived in formula,and the period of switching sine wave is given in formula under the restriction of capacitor voltage ripple.Finally,a comprehensive control strategy is presented and the simulation results verify the feasibility and effectiveness of FMMC-SLFAC.
作者
欧朱建
王广柱
OU Zhujian;WANG Guangzhu(Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education（Shandong University）,Jinan 250061,China)
出处
《电力系统自动化》
EI
CSCD
北大核心
2018年第21期111-118,171,共9页
Automation of Electric Power Systems
基金
国家自然科学基金资助项目(51541708)~~
关键词
单相低频输电
功率波动
模块化多电平变换器
拟方波
电容电压纹波
single phase low frequency AC （SLFAC）transmission
power ripple
modular multilevel converter
quasi-squarewave
capacitor voltage ripple
作者简介
欧朱建（1989-），男，博士研究生，主要研究方向：多电平变换器及低频输电技术。E-mail：zj_ou89@163．com;王广柱（1963-），男，通信作者，博士，教授，博士生导师，主要研究方向：现代电力电子技术及应用。E-mail：sdwgz@sdu．edu．cn
