基于虚拟同步机的并网逆变器不平衡电压灵活补偿策略
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摘要
电力电子设备大量地接入电网,给电网带来了系统惯量和阻尼降低等问题。为了提高不平衡电网频率稳定性和改善电网电压的电能质量,提出了基于虚拟同步机的不平衡电压灵活补偿控制策略。通过采用虚拟同步控制,在电网频率波动时提供有功功率支撑,提高电网频率稳定性。通过采用负序电压前馈补偿,抑制公共连接点不平衡电压,改善电能质量。通过建立不平衡电网下的虚拟同步机模型,提出采用电压前馈的不平衡电压抑制策略。进而,分析了采用电压前馈补偿策略的控制性能,研究不平衡电压补偿系数的设定方法。提出的控制方法可根据电网电压不平衡度的控制目标和设备剩余容量自动地调整不平衡电压补偿系数,实现不平衡度灵活调节。最后,通过仿真结果验证所提控制策略的正确性和有效性。
With a large number of power electronics devices connected to the power grid,there are problems,such as inertia and damping decreasing.To improve the frequency stability and power quality of the unbalanced grid,this paper proposes a flexible compensation control strategy of unbalanced voltage based on virtual synchronous generator(VSG).When the frequency of the grid is oscillating,VSG can provide active power support to enhance the stability of power system.By using the feed-forward compensation control of negative sequence voltage,it can restrain the unbalanced voltage at the point the of common coupling and improve the power quality.By building the model of VSG under unbalanced grid,this paper proposes a suppression strategy of unbalanced voltage by using the voltage feed-forward compensation.Then,the performance of voltage feed-forward compensation strategy is analyzed and the compensation coefficient setting method of the unbalanced voltage is studied.The method can realize flexible control,which changes the compensation coefficient automatically according to the goal of voltage unbalanced factor and the remaining capacity of instrument.Finally,simulation results validate the correctness and effectiveness of proposed control strategy.
With a large number of power electronics devices connected to the power grid,there are problems,such as inertia and damping decreasing.To improve the frequency stability and power quality of the unbalanced grid,this paper proposes a flexible compensation control strategy of unbalanced voltage based on virtual synchronous generator(VSG).When the frequency of the grid is oscillating,VSG can provide active power support to enhance the stability of power system.By using the feed-forward compensation control of negative sequence voltage,it can restrain the unbalanced voltage at the point the of common coupling and improve the power quality.By building the model of VSG under unbalanced grid,this paper proposes a suppression strategy of unbalanced voltage by using the voltage feed-forward compensation.Then,the performance of voltage feed-forward compensation strategy is analyzed and the compensation coefficient setting method of the unbalanced voltage is studied.The method can realize flexible control,which changes the compensation coefficient automatically according to the goal of voltage unbalanced factor and the remaining capacity of instrument.Finally,simulation results validate the correctness and effectiveness of proposed control strategy.
引文
[1]曾正,赵荣祥,汤胜清,等.可再生能源分散接入用先进并网逆变器研究综述[J].中国电机工程学报,2013,33(24):1-12.ZENG Zheng,ZHAO Rongxiang,TANG Shengqing,et al.An overview on advanced grid-connected inverters used for decentralized renewable energy resources[J].Proceedings of the CSEE,2013,33(24):1-12.
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[5]丁明,杨向真,苏建徽.基于虚拟同步发电机思想的微电网逆变电源控制策略[J].电力系统自动化,2009,33(8):89-93.DING Ming,YANG Xiangzhen,SU Jianhui.Control strategies of inverters based on virtual synchronous generator in a microgrid[J].Automation of Electric Power Systems,2009,33(8):89-93.
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[10]陈天一,陈来军,汪雨辰,等.考虑不平衡电网电压的虚拟同步发电机平衡电流控制方法[J].电网技术,2016,40(3):904-909.CHEN Tianyi,CHEN Laijun,WANG Yuchen,et al.Balanced current control of virtual synchronous generator considering unbalanced grid voltage[J].Power Systems Technology,2016,40(3):904-909.
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[14]程学坤,孙旭东,柴建云,等.适用于电网不对称故障的双馈风力发电机虚拟同步控制策略[J].电力系统自动化,2018,42(9):120-126.DOI:10.7500/AEPS20171025030.CHENG Xuekun,SUN Xudong,CHAI Jianyun,et al.Virtual synchronous control strategy for doubly-fed induction generator under asymmetrical grid faults[J].Automation of Electric Power Systems,2018,42(9):120-126.DOI:10.7500/AEPS20171025030.
[15]何安然,侯凯,王小红,等.不对称条件下的储能虚拟同步发电机低电压穿越控制技术[J].电力系统自动化,2018,42(10):122-127.DOI:10.7500/AEPS20170605004.HE Anran,HOU Kai,WANG Xiaohong,et al.A low voltage ride through control technique for energy storage virtual synchronous generator under asymmetric condition[J].Automation of Electric Power Systems,2018,42(10):122-127.DOI:10.7500/AEPS20170605004.
[16]电能质量三相电压不平衡:GB/T 15543-2008[S].北京:中国国家标准化管理委员会,2008.Power quality three-phase voltage unbalance:GB/T 15543-2008[S].Beijing:China national standardization administration,2008.
[17]李小叶,李永丽,张玮亚,等.基于多功能并网逆变器的电能质量控制策略[J].电网技术,2015,39(2):556-562.LI Xiaoye,LI Yongli,ZHANG Weiya,et al.A power quality control strategy based on multi-functional grid-connected inverter[J].Power Systems Technology,2015,39(2):556-562.
[18]曾正,杨欢,赵荣祥,等.多功能并网逆变器研究综述[J].电力自动化设备,2012,32(8):5-15.ZENG Zheng,YANG Huan,ZHAO Rongxiang,et al.Overview of multi-functional grid-connected inverters[J].Power Automation Equipment,2012,32(8):5-15.
[19]年珩,王涛,程鹏.适应实际电网阻抗特性的DFIG不平衡电压解耦补偿技术[J].电力系统自动化,2015,39(23):49-57.DOI:10.7500/AEPS20150324004.NIAN Heng,WANG Tao,CHENG Peng.An unbalanced voltage decoupling compensation technique for DFIG adaptive to grid impedance[J].Automation of Electric Power Systems,2015,39(23):49-57.DOI:10.7500/AEPS20150324004.
[20]SHI Hongtao,ZHUO Fang,YI Hao,et al.Control strategy for microgrid under three phase unbalanced condition[J].Journal of Modern Power Systems and Clean Energy,2018,4(1):94-102.
[2]张兴,张崇巍.PWM可逆变流器空间电压矢量控制技术的研究[J].中国电机工程学报,2001,21(10):103-106.ZHANG Xing,ZHANG Chongwei.Study on a new space voltage vector control method about reversible PWM converter[J].Proceedings of the CSEE,2001,21(10):103-106.
[3]HU Jiabing,SHANG Lei,HE Yikang,et al.Direct active and reactive power regulation of grid-connected DC/AC converters using sliding mode control approach[J].IEEE Transactions on Power Electronics,2011,26(1):210-222.
[4]HUANG Linbin,XIN Huanhai,WANG Zhen,et al.A virtual synchronous control for voltage-source converters utilizing dynamics of DC-link capacitor to realize self-synchronization[J].IEEE Journal of Emerging and Selected Topics in Power Electronics,2017,5(4):1565-1577.
[5]丁明,杨向真,苏建徽.基于虚拟同步发电机思想的微电网逆变电源控制策略[J].电力系统自动化,2009,33(8):89-93.DING Ming,YANG Xiangzhen,SU Jianhui.Control strategies of inverters based on virtual synchronous generator in a microgrid[J].Automation of Electric Power Systems,2009,33(8):89-93.
[6]钟庆昌.虚拟同步机与自主电力系统[J].中国电机工程学报,2017,37(2):336-349.ZHONG Qingchang.Virtual synchronous machines and autonomous power systems[J].Proceedings of the CSEE,2017,37(2):336-349.
[7]JIA Liu,YUSHI M,TOSHIFUMI I.Comparison of dynamic characteristics between virtual synchronous generator and droop control in inverter-based distributed generators[J].IEEETransactions on Power Electronics,2016,31(05):3600-3611.
[8]石荣亮,张兴,徐海珍,等.基于虚拟同步发电机的微网运行模式无缝切换控制策略[J].电力系统自动化,2016,40(10):16-23.DOI:10.7500/AEPS20150615012.SHI Rongliang,ZHANG Xing,XU Haizhen,et al.Seamless switching control strategy for microgrid operation modes on virtual synchronous generator[J].Automation of Electric Power Systems,2016,40(10):16-23.DOI:10.7500/AEPS20150615012.
[9]郑天文,陈来军,陈天一,等.虚拟同步发电机技术及展望[J].电力系统自动化,2015,39(21):165-175.DOI:10.7500/AEPS20150508006.ZHENG Tianwen,CHEN Laijun,CHEN Tianyi,et al.Review and prospect of virtual synchronous generator technologies[J].Automation of Electric Power Systems,2015,39(21):165-175.DOI:10.7500/AEPS20150508006.
[10]陈天一,陈来军,汪雨辰,等.考虑不平衡电网电压的虚拟同步发电机平衡电流控制方法[J].电网技术,2016,40(3):904-909.CHEN Tianyi,CHEN Laijun,WANG Yuchen,et al.Balanced current control of virtual synchronous generator considering unbalanced grid voltage[J].Power Systems Technology,2016,40(3):904-909.
[11]万晓凤,胡海林,聂晓艺,等.电网电压不平衡时的改进虚拟同步机控制策略[J].电网技术,2017,41(11):3573-3581.WAN Xiaofeng,HU Hailin,NIE Xiaoyi,et al.An improved control strategy for virtual synchronous generator under unbalanced grid voltage[J].Power System Technology,2017,41(11):3573-3581.
[12]ZHENG T,CHEN L,GUO Y,et al.Flexible unbalanced control with peak current limitation for virtual synchronous generator under voltage sags[J].Journal of Modern Power Systems and Clean Energy,2018,6(1):61-72.
[13]肖湘宁,陈萌.不平衡电压下虚拟同步发电机功率控制策略[J].电力自动化设备,2017,37(8):193-200.XIAO Xiangning,CHEN Meng.Power control of virtual synchronous generator under unbalanced grid voltage[J].Electric Power Automation Equipment,2017,37(8):193-200.
[14]程学坤,孙旭东,柴建云,等.适用于电网不对称故障的双馈风力发电机虚拟同步控制策略[J].电力系统自动化,2018,42(9):120-126.DOI:10.7500/AEPS20171025030.CHENG Xuekun,SUN Xudong,CHAI Jianyun,et al.Virtual synchronous control strategy for doubly-fed induction generator under asymmetrical grid faults[J].Automation of Electric Power Systems,2018,42(9):120-126.DOI:10.7500/AEPS20171025030.
[15]何安然,侯凯,王小红,等.不对称条件下的储能虚拟同步发电机低电压穿越控制技术[J].电力系统自动化,2018,42(10):122-127.DOI:10.7500/AEPS20170605004.HE Anran,HOU Kai,WANG Xiaohong,et al.A low voltage ride through control technique for energy storage virtual synchronous generator under asymmetric condition[J].Automation of Electric Power Systems,2018,42(10):122-127.DOI:10.7500/AEPS20170605004.
[16]电能质量三相电压不平衡:GB/T 15543-2008[S].北京:中国国家标准化管理委员会,2008.Power quality three-phase voltage unbalance:GB/T 15543-2008[S].Beijing:China national standardization administration,2008.
[17]李小叶,李永丽,张玮亚,等.基于多功能并网逆变器的电能质量控制策略[J].电网技术,2015,39(2):556-562.LI Xiaoye,LI Yongli,ZHANG Weiya,et al.A power quality control strategy based on multi-functional grid-connected inverter[J].Power Systems Technology,2015,39(2):556-562.
[18]曾正,杨欢,赵荣祥,等.多功能并网逆变器研究综述[J].电力自动化设备,2012,32(8):5-15.ZENG Zheng,YANG Huan,ZHAO Rongxiang,et al.Overview of multi-functional grid-connected inverters[J].Power Automation Equipment,2012,32(8):5-15.
[19]年珩,王涛,程鹏.适应实际电网阻抗特性的DFIG不平衡电压解耦补偿技术[J].电力系统自动化,2015,39(23):49-57.DOI:10.7500/AEPS20150324004.NIAN Heng,WANG Tao,CHENG Peng.An unbalanced voltage decoupling compensation technique for DFIG adaptive to grid impedance[J].Automation of Electric Power Systems,2015,39(23):49-57.DOI:10.7500/AEPS20150324004.
[20]SHI Hongtao,ZHUO Fang,YI Hao,et al.Control strategy for microgrid under three phase unbalanced condition[J].Journal of Modern Power Systems and Clean Energy,2018,4(1):94-102.