不平衡电网电压条件下光储微电网并网控制
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摘要
混合储能型光伏并网系统不仅有效解决了传统光伏发电的随机性和波动性,同时克服了单一储能系统功率密度与能量密度相矛盾的不足。但电网电压的不平衡则会使光储微网系统的输出电能质量下降,并且逆变器侧会出现过流现象,进而影响了整个系统的运行稳定性。为抑制储能变换器中电流及系统入网功率的二倍频脉动,提高并网电能质量,在两相静止坐标系下,分析了并网电流参考值的谐波与过流问题,提出带有功率补偿的限流模型预测直接功率控制;在混合储能系统控制结构中引入二倍频陷波器,并结合模型预测电流控制,实现了系统的快速动态响应以及高电能质量入网。在MATLAB/Simulink中搭建了系统仿真模型,并针对不同工况进行了仿真验证。仿真结果表明:在不平衡电网电压下,所提控制策略可平抑储能变换器中电流与逆变器中输出功率的二次脉动,同时在实现对有功、无功功率及负序电流协调控制时,可实现对故障过电流的抑制。
The photovoltaic(PV) grid-connected system with hybrid energy storage(HESS) not only effectively solves the randomness and fluctuation of traditional PV power generation, but also overcomes the contradiction between the power density and the energy density of a single energy storage system. However, the output power quality will be worse, and the overcurrent will appear on the inverter side under unbalanced grid voltage condition. This will affect the operation stability of the entire system. In order to restrain the doubling frequency pulsation of the current in the energy storage converter, and secondary pulsation in grid-connected power in order to improve the power quality; the harmonics and overcurrent problems of the grid current reference value are analyzed in the two-phase stationary coordinate system. The current-limited model predictive direct power control(MPDPC) with power compensation is proposed. The double frequency notch filter is introduced in HESS, combining with the model predictive current control, the fast-dynamic response of the system and the high-power quality are realized. The system simulation model has been built in MATLAB/Simulink and tested for different working conditions. Simulation results show that the proposed control strategy can stabilize the secondary ripple of the current in the energy storage converter, and the output power of the inverter.At the same time this can achieve the suppression of the fault overcurrent during the coordinated control of the active/reactive power, and the negative sequence current under imbalanced grid voltage.
The photovoltaic(PV) grid-connected system with hybrid energy storage(HESS) not only effectively solves the randomness and fluctuation of traditional PV power generation, but also overcomes the contradiction between the power density and the energy density of a single energy storage system. However, the output power quality will be worse, and the overcurrent will appear on the inverter side under unbalanced grid voltage condition. This will affect the operation stability of the entire system. In order to restrain the doubling frequency pulsation of the current in the energy storage converter, and secondary pulsation in grid-connected power in order to improve the power quality; the harmonics and overcurrent problems of the grid current reference value are analyzed in the two-phase stationary coordinate system. The current-limited model predictive direct power control(MPDPC) with power compensation is proposed. The double frequency notch filter is introduced in HESS, combining with the model predictive current control, the fast-dynamic response of the system and the high-power quality are realized. The system simulation model has been built in MATLAB/Simulink and tested for different working conditions. Simulation results show that the proposed control strategy can stabilize the secondary ripple of the current in the energy storage converter, and the output power of the inverter.At the same time this can achieve the suppression of the fault overcurrent during the coordinated control of the active/reactive power, and the negative sequence current under imbalanced grid voltage.
引文
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[9]孙黎霞,王哲,朱鹏飞,等.电网电压不平衡时VSC-HVDC优化控制策略[J].高电压技术,2016,42(1):47-55.SUN Lixia,WANG Zhe,ZHU Pengfei,et al.Optimization control strategy for VSC-HVDC with unbalanced grid voltage conditions[J].High Voltage Engineering,2016,42(1):47-55.
[10]孙小燕,朱永强,贾利虎,等.电网不对称故障下光伏逆变器预测控制方法[J].电力系统自动化,2015,39(13):81-86.SUN Xiaoyan,ZHU Yongqiang,JIA Lihu,et al.Predictive control method for photovoltaic inverter under power grid unsymmetrical fault[J].Automation of Electric Power Systems,2015,39(13):81-86.
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[12]姜卫东,汪磊,王永生,等.电网不平衡时采用改进无差拍控制的并网变流器不同约束条件的实现[J].中国电机工程学报,2017,7(6):1777-1786.JIANG Weidong,WANG Lei,WANG Yongsheng,et al.Implementations of different constraint conditions based on improved deadbeat control for grid-connected converter under unbalanced grid voltage[J].Proceedings of the CSEE,2017,37(6):1777-1786.
[13]郭旭刚,高增伟,尹靖元,等.不平衡电网电压下的PWM整流器功率预测[J].电网技术,2013,37(8):2362-2367.GUO Xugang,GAO Zengwei,YIN Jingyuan,et al.Predictive direct power control for PWM rectifier under unbalanced grid voltage conditions[J].Power System Technology,2013,37(8):2362-2367.
[14]NIAN H,SHEN Y,YANG H,et al.Flexible grid connection technique of voltage-source inverter under unbalanced grid conditions based on direct power control[J].IEEE Transactions on Industry Applications,2015,51(5):4041-4050.
[15]宋平岗,吴继珍,邹欢.电网电压不平衡时模块化多电平换流器直接功率补偿控制策略[J].高电压技术,2016,42(7):2184-2192.SONG Pinggang,WU Jizhen,ZOU Huan.Direct power compensation control strategy for modular multilevel converter under unbalanced grid voltage conditions[J].High Voltage Engineering,2016,42(7):2184-2192.
[16]张永昌,曲昌琦.不平衡电网下脉宽调制整流器模型预测直接功率控制[J].电力系统自动化,2015,39(4):69-75.ZHANG Yongchang,QU Changqi.Model predictive direct power control of PWM rectifier under unbalanced grid voltage condition[J].Automation of Electric Power Systems,2015,39(4):69-75.
[17]JIN N,HU S,GAN C,et al.Finite states model predictive control for fault tolerant operation of three-phase bidirectional AC/DC converter under unbalanced grid voltages[J].IEEE Transactions on Industrial Electronics,2018,65(1):819-829.
[18]谭骞,徐永海,黄浩,等.不对称电压暂降情况下光伏逆变器输出电流峰值的控制策略[J].电网技术,2015,39(3):601-608.TAN Qian,XU Yonghai,HUANG Hao,et al.A control strategy for peak output current of PV inverter under unbalanced voltage sags[J].Power System Technology,2015,39(3):601-608.
[19]郭小强,刘文钊,王宝诚,等.光伏并网逆变器不平衡故障穿越限流控制策略[J].中国电机工程学报,2015,35(20):5155-5162.GUO Xiaoqiang,LIU Wenzhao,WANG Baocheng,et al.Fault ride through control of PV grid-connected inverter with current-limited capability under unbalanced grid voltage conditions[J].Proceedings of the CSEE,2015,35(20):5155-5162.
[20]王成山,李微,王议锋,等.直流微电网母线电压波动分类及抑制方法综述[J].中国电机工程学报,2017,37(1):84-97.WANG Chengshan,LI Wei,WANG Yifeng,et al.DC bus voltage fluctuation classification and restraint methods review for DC microgrid[J].Proceedings of the CSEE,2017,37(1):84-97.
[21]周小平,罗安,陈燕东,等.直流微电网中双向储能变换器的二次纹波电流抑制与不均衡控制策略[J].电网技术,2016,40(9):2682-2688.ZHOU Xiaoping,LUO An,CHEN Yandong,et al.Secondary ripple current suppression and imbalance control strategy in bidirectional storage converter of DC microgrid[J].Power System Technology,2016,40(9):2682-2688.
[22]祝国平,阮新波,王学华,等.两级式单相逆变器二次纹波电流的抑制与动态特性的改善[J].中国电机工程学报,2013,33(12):72-80.ZHU Guoping,RUAN Xinbo,WANG Xuehua,et al.Suppression of the second harmonic current and improvement of the dynamic performance for two-stage single-phase inverters[J].Proceedings of the CSEE,2013,33(12):72-80.
[23]AHMADI R,SAJADIAN S.Model predictive control of dual-mode operations Z-source inverter:islanded and grid-connected[J].IEEETransactions on Power Electronics,2017,33(5):4488-4497.
[24]于明,王毅,李永刚.基于预测方法的直流微网混合储能虚拟惯性控制[J].电网技术,2017,41(5):1526-1532.YU Ming,WANG Yi,LI Yonggang.Virtual inertia control of hybrid energy storage in DC microgrid based on predictive method[J].Power System Technology,2017,41(5):1526-1532.
[2]程启明,徐聪,程尹曼,等.基于混合储能技术的光储式充电站直流微网系统协调控制[J].高电压技术,2016,42(7):2073-2083.CHENG Qiming,XU Cong,CHENG Yinman,et al.Coordination control of PV charging station DC microgrid system based on hybrid energy storage technology[J].High Voltage Engineering,2016,42(7):2073-2083.
[3]MANANDHAR U,TUMMURU N R,KUMAR S,et al.Validation of faster joint control strategy for battery and supercapacitor based energy storage system[J].IEEE Transactions on Industrial Electronics,2018,65(4):3286-3295.
[4]KORADA N,MISHRA M K.Grid adaptive power management strategy for an integrated microgrid with hybrid energy storage[J].IEEETransactions on Industrial Electronics,2017,64(4):2884-2892.
[5]程志江,李永东,谢永流,等.带超级电容的光伏发电微网系统混合储能控制策略[J].电网技术,2015,39(10):2739-2745.CHENG Zhijiang,LI Yongdong,XIE Yongliu,et al.Control strategy for hybrid energy storage of photovoltaic generation microgrid system with super capacitor[J].Power System Technology,2015,39(10):2739-2745.
[6]阳同光,桂卫华.电网不平衡情况下并网逆变器控制策略综述[J].电工技术学报,2015,30(14):241-246.YANG Tongguang,GUI Weihua.An overview on control strategies of grid-connected inverter under unbalanced voltage conditions[J].Transactions of China Electrotechnical Society,2015,30(14):241-246.
[7]林永朋,陶顺,肖湘宁.电压不平衡条件下并网逆变器的直流电压控制[J].电网技术,2015,39(6):1643-1649.LIN Yongpeng,TAO Shun,XIAO Xiangning.DC voltage control of grid-connected inverters under imbalanced voltage[J].Power System Technology,2015,39(6):1643-1649.
[8]伞国成,漆汉宏,魏艳君,等.基于复功率的电网电压不平衡条件下并网逆变器控制策略[J].电工技术学报,2017,32(8):229-236.SAN Guocheng,QI Hanhong,WEI Yanjun,et al.Complex power based control strategy of grid-connected inverter under unbalanced grid voltage conditions[J].Transactions of China Electrotechnical Society,2017,32(8):229-236.
[9]孙黎霞,王哲,朱鹏飞,等.电网电压不平衡时VSC-HVDC优化控制策略[J].高电压技术,2016,42(1):47-55.SUN Lixia,WANG Zhe,ZHU Pengfei,et al.Optimization control strategy for VSC-HVDC with unbalanced grid voltage conditions[J].High Voltage Engineering,2016,42(1):47-55.
[10]孙小燕,朱永强,贾利虎,等.电网不对称故障下光伏逆变器预测控制方法[J].电力系统自动化,2015,39(13):81-86.SUN Xiaoyan,ZHU Yongqiang,JIA Lihu,et al.Predictive control method for photovoltaic inverter under power grid unsymmetrical fault[J].Automation of Electric Power Systems,2015,39(13):81-86.
[11]张永昌,彭玉宾,曲昌琦.不平衡电网电压下的PWM整流器预测电流控制[J].电工技术学报,2016,31(4):88-94.ZHANG Yongchang,PENG Yubin,QU Changqi.Predictive current control of PWM rectifier under unbalanced grid voltage condition[J].Transactions of China Electrotechnical Society,2016,31(4):88-94.
[12]姜卫东,汪磊,王永生,等.电网不平衡时采用改进无差拍控制的并网变流器不同约束条件的实现[J].中国电机工程学报,2017,7(6):1777-1786.JIANG Weidong,WANG Lei,WANG Yongsheng,et al.Implementations of different constraint conditions based on improved deadbeat control for grid-connected converter under unbalanced grid voltage[J].Proceedings of the CSEE,2017,37(6):1777-1786.
[13]郭旭刚,高增伟,尹靖元,等.不平衡电网电压下的PWM整流器功率预测[J].电网技术,2013,37(8):2362-2367.GUO Xugang,GAO Zengwei,YIN Jingyuan,et al.Predictive direct power control for PWM rectifier under unbalanced grid voltage conditions[J].Power System Technology,2013,37(8):2362-2367.
[14]NIAN H,SHEN Y,YANG H,et al.Flexible grid connection technique of voltage-source inverter under unbalanced grid conditions based on direct power control[J].IEEE Transactions on Industry Applications,2015,51(5):4041-4050.
[15]宋平岗,吴继珍,邹欢.电网电压不平衡时模块化多电平换流器直接功率补偿控制策略[J].高电压技术,2016,42(7):2184-2192.SONG Pinggang,WU Jizhen,ZOU Huan.Direct power compensation control strategy for modular multilevel converter under unbalanced grid voltage conditions[J].High Voltage Engineering,2016,42(7):2184-2192.
[16]张永昌,曲昌琦.不平衡电网下脉宽调制整流器模型预测直接功率控制[J].电力系统自动化,2015,39(4):69-75.ZHANG Yongchang,QU Changqi.Model predictive direct power control of PWM rectifier under unbalanced grid voltage condition[J].Automation of Electric Power Systems,2015,39(4):69-75.
[17]JIN N,HU S,GAN C,et al.Finite states model predictive control for fault tolerant operation of three-phase bidirectional AC/DC converter under unbalanced grid voltages[J].IEEE Transactions on Industrial Electronics,2018,65(1):819-829.
[18]谭骞,徐永海,黄浩,等.不对称电压暂降情况下光伏逆变器输出电流峰值的控制策略[J].电网技术,2015,39(3):601-608.TAN Qian,XU Yonghai,HUANG Hao,et al.A control strategy for peak output current of PV inverter under unbalanced voltage sags[J].Power System Technology,2015,39(3):601-608.
[19]郭小强,刘文钊,王宝诚,等.光伏并网逆变器不平衡故障穿越限流控制策略[J].中国电机工程学报,2015,35(20):5155-5162.GUO Xiaoqiang,LIU Wenzhao,WANG Baocheng,et al.Fault ride through control of PV grid-connected inverter with current-limited capability under unbalanced grid voltage conditions[J].Proceedings of the CSEE,2015,35(20):5155-5162.
[20]王成山,李微,王议锋,等.直流微电网母线电压波动分类及抑制方法综述[J].中国电机工程学报,2017,37(1):84-97.WANG Chengshan,LI Wei,WANG Yifeng,et al.DC bus voltage fluctuation classification and restraint methods review for DC microgrid[J].Proceedings of the CSEE,2017,37(1):84-97.
[21]周小平,罗安,陈燕东,等.直流微电网中双向储能变换器的二次纹波电流抑制与不均衡控制策略[J].电网技术,2016,40(9):2682-2688.ZHOU Xiaoping,LUO An,CHEN Yandong,et al.Secondary ripple current suppression and imbalance control strategy in bidirectional storage converter of DC microgrid[J].Power System Technology,2016,40(9):2682-2688.
[22]祝国平,阮新波,王学华,等.两级式单相逆变器二次纹波电流的抑制与动态特性的改善[J].中国电机工程学报,2013,33(12):72-80.ZHU Guoping,RUAN Xinbo,WANG Xuehua,et al.Suppression of the second harmonic current and improvement of the dynamic performance for two-stage single-phase inverters[J].Proceedings of the CSEE,2013,33(12):72-80.
[23]AHMADI R,SAJADIAN S.Model predictive control of dual-mode operations Z-source inverter:islanded and grid-connected[J].IEEETransactions on Power Electronics,2017,33(5):4488-4497.
[24]于明,王毅,李永刚.基于预测方法的直流微网混合储能虚拟惯性控制[J].电网技术,2017,41(5):1526-1532.YU Ming,WANG Yi,LI Yonggang.Virtual inertia control of hybrid energy storage in DC microgrid based on predictive method[J].Power System Technology,2017,41(5):1526-1532.