独立微网中多虚拟同步机功率精确分配控制策略
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摘要
独立微网中,逆变器采用虚拟同步发电机(Virtual Synchronous Generator, VSG)控制模拟同步发电机运行机制,为微网提供惯性和阻尼,改善系统电压频率稳定性。但传统VSG并联系统不具备无功出力合理分配以及直流抑制的能力。首先,从VSG基本原理入手,分析了VSG功率均分机理。其次,为构造积分器,从电压补偿角度提出了一种改进的无功控制方法,实现了无功分配与线路阻抗解耦。在直流抑制方面,利用准谐振控制器重新设计了底层双环控制。同时研究了参数匹配方法,保证VSG功率均分。最后通过Matlab仿真验证了所提策略的正确性和有效性。
To provide inertia and damping for the system and to improve the stability of voltage and frequency in independent micro-grid, Virtual Synchronous Generator(VSG) control strategy of inverters is recommended, which mimics synchronous generators. However, the traditional VSG parallel system is challenged by rational distribution of reactive power and DC suppression. Firstly, the accurate power sharing mechanism of VSG is analyzed based on the principle of VSG. Besides, an improved reactive power control method is proposed from the angle of voltage compensation to construct the integrator, which can realize the decoupling of reactive power distribution and line impedance. Furthermore, the double loop control is redesigned to suppress the DC by using the quasi resonant controller. At the same time, the method of parameter matching is studied to ensure the accurate power sharing of VSG. Finally, the validity and effectiveness of the proposed VSG control are verified by Matlab simulation.
To provide inertia and damping for the system and to improve the stability of voltage and frequency in independent micro-grid, Virtual Synchronous Generator(VSG) control strategy of inverters is recommended, which mimics synchronous generators. However, the traditional VSG parallel system is challenged by rational distribution of reactive power and DC suppression. Firstly, the accurate power sharing mechanism of VSG is analyzed based on the principle of VSG. Besides, an improved reactive power control method is proposed from the angle of voltage compensation to construct the integrator, which can realize the decoupling of reactive power distribution and line impedance. Furthermore, the double loop control is redesigned to suppress the DC by using the quasi resonant controller. At the same time, the method of parameter matching is studied to ensure the accurate power sharing of VSG. Finally, the validity and effectiveness of the proposed VSG control are verified by Matlab simulation.
引文
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[2]WANG Z,CHEN B,WANG J,et al.Decentralized energy management system for networked microgrids in grid-connected and islanded modes[J].IEEE Transactions on Smart Grid,2016,7(2):1097-1105.
[3]GUO Wenming,MU Longhua.Control principles of micro-source inverters used in microgrid[J].Protection and Control of Modern Power Systems,2016,1(1):56-62.DOI:10.1186/s41601-016-0019-8.
[4]张东,陈景文,张蓉,等.计及光伏预测的直流微电网能量调度研究[J].智慧电力,2018,46(2):28-33.ZHANG Dong,CHEN Jingwen,ZHANG Rong,et al.Energy dispatching of DC microgird based on pv generation prediction[J].Smart Power,2018,46(2):28-33.
[5]XU Jianzhong,ZHAO Chengyong.A coherency-based equivalence method for MMC inverters using virtual synchronous generator control[J].IEEE Transactions on Power Delivery,2016,31(3):1369-1378.
[6]吕志鹏.虚拟同步机技术构建“源-网-荷”友好互动新模式[J].供用电,2017,34(2):32-34,27.LüZhipeng.New pattern of source-grid-load friendly interaction based on virtual synchronous machine technology[J].Distribution&Utilization,2017,34(2):32-34,27.
[7]张宸宇,杨赟,袁晓冬,等.考虑阻尼和惯性的虚拟同步机建模方法研究[J].电力工程技术,2018,37(5):45-49.ZHANG Chenyu,YANG Yun,YUAN Xiaodong,et al.Modeling method of virtual synchronous machine considering damping and inertia[J].Electric Power Engineering Technology,2018,37(5):45-49.
[8]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.ZHENG Tianwen,CHEN Laijun,CHEN Tianyi,et al.Technology and prospect of virtual synchronous generator[J].Automation of Electric Power Systems,2015,39(21):165-175.
[9]徐少华,李建林,惠东.多储能逆变器并联系统在微网孤岛条件下的稳定性分析及其控制策略[J].高电压技术,2015,41(10):3266-3273.XU Shaohua,LI Jianlin,HUI Dong.Stability analysis and control strategy of parallel storage inverter system working under the micro-gird’s island condition[J].High Voltage Engineering,2015,41(10):3266-3273.
[10]陈刚,蒋顺平,丁勇,等.并联T型三电平储能变流器零序环流抑制[J].电力工程技术,2017,36(5):52-58.CHEN Gang,JIANG Shunping,DING Yong,et al.Zero-sequence circulating current reduction for parallel T-type three-level power converter systems[J].Electric Power Engineering Technology,2017,36(5):52-58.
[11]樊晨曦,李海锋,AZEDDINE H,等.三相逆变器并联系统中环流抑制的研究[J].智慧电力,2018,46(5):15-21.FAN Chenxi,LI Haifeng,AZEDDINE H,et al.Study on circulating current suppression in three-phase inverter parallel system[J].Smart Power,2018,46(5):15-21.
[12]程启明,张宇,谭冯忍,等.基于Washout滤波器的虚拟同步发电机新型控制方法研究[J].电力系统保护与控制,2017,45(16):51-57.CHENG Qiming,ZHANG Yu,TAN Fengren,et al.Research on new control method of virtual synchronous generator based on Washout filter[J].Power System Protection and Control,2017,45(16):51-57.
[13]彭湃.基于虚拟阻抗的微电网下垂控制策略研究[J].供用电,2018,35(6):60-65.PENG Pai.Research on droop control strategy in micro-grid based on virtual impedance[J].Distribution&Utilization,2018,35(6):60-65.
[14]刘海涛,吕志鹏,苏剑,等.具有功率精确分配能力的逆变器电压谐波分频下垂控制方法研究[J].电力系统保护与控制,2015,43(19):9-14.LIU Haitao,LüZhipeng,SU Jian,et al.Inverter’s frequency dividing droop controller with accurate load sharing ability[J].Power System Protection and Control,2015,43(19):9-14.
[15]赵济乾,赵晋斌,孙锋,等.基于可控等效输出阻抗的微网逆变器并联特性研究[J].电力系统保护与控制,2017,45(6):94-100.ZHAO Jiqian,ZHAO Jinbin,SUN Feng,et al.Research on microgrid inverters parallel characteristic based controllable equivalent output impedance[J].Power System Protection and Control,2017,45(6):94-100.
[16]郭倩,林燎源,武宏彦,等.一种改进的分布式电源无功功率精确分配下垂控制策略[J].电力系统自动化,2015,39(15):30-34,74.GUO Qian,LIN Liaoyuan,WU Hongyan,et al.An improved droop control strategy for accurate reactive power sharing among distributed generators[J].Automation of Electric Power Systems,2015,39(15):30-34,74.
[17]祝钧,李瑞生,毋炳鑫,等.交直流混合微电网接口变换器虚拟同步发电机控制方法[J].电力系统保护与控制,2017,45(11):28-34.ZHU Jun,LI Ruisheng,WU Bingxin,et al.Virtual synchronous generator operation of interlinking converter between AC and DC microgrids[J].Power System Protection and Control,2017,45(11):28-34.
[18]ROCABERT J,LUNA A,BLAABJERG F,et al.Control of power converters in AC microgrids[J].IEEE Transactions on Power Electronics,2012,27(11):4734-4749.
[19]黄媛,罗安,陈燕东,等.一种三阶广义积分交叉对消电流反馈控制的多逆变器并联控制策略[J].中国电机工程学报,2014,34(28):4855-4864.HUANG Yuan,LUO An,CHEN Yandong,et al.Acurrent feedback control strategy for parallel operation of multi-inverters using third-order general-integrator crossover cancellation method[J].Proceedings of the CSEE,2014,34(28):4855-4864.
[20]石荣亮,张兴,刘芳,等.不平衡与非线性混合负载下的虚拟同步发电机控制策略[J].中国电机工程学报,2016,36(22):6086-6095.SHI Rongliang,ZHANG Xing,LIU Fang,et al.A control strategy for unbalanced and nonlinear mixed loads of virtual synchronous generators[J].Proceedings of the CSEE,2016,36(22):6086-6095.
[21]张波,颜湘武,黄毅斌,等.虚拟同步机多机并联稳定控制及其惯量匹配方法[J].电工技术学报,2017,32(10):42-52.ZHANG Bo,YAN Xiangwu,HUANG Yibin,et al.Stability control and inertia matching method of multiparallel virtual synchronous generators[J].Transactions of China Electrotechnical Society,2017,32(10):42-52.