弱电网下基于模型预测控制的NPC三电平LCL型并网逆变器谐振抑制方法研究*

doi:10.11985/2021.02.024

摘要/Abstract

摘要：

为了抑制弱电网下NPC三电平LCL型并网逆变器系统存在的谐振,提高输出电能质量,同时抑制直流侧中点电压波动,建立了弱电网下三电平LCL型并网逆变器的逆变器侧电流和直流侧中点电压的预测模型。针对LCL型滤波器存在的谐振问题,从预测模型角度出发,提出了采用电容电压基频分量的MPC-i₁u_c_{_}_f谐振抑制策略,消除了谐振分量对系统的影响,进而实现了弱电网电感变化时系统谐振的抑制。与现有模型预测控制下的谐振抑制方法相比,所提方法降低了参数设计的复杂性,易于工程实现。试验结果显示,弱电网下所提出的MPC-i₁u_c_{_}_f方法能够实现系统谐振抑制,并网电流的控制良好,同时兼顾直流侧中点电压平衡。

关键词: 弱电网, LCL, 谐振抑制, 中点电压, 模型预测控制

Abstract:

In order to suppress the system resonance of the LCL-filtered NPC 3-level grid-connected inverter under the weak grid, improve the output power quality, and at the same time suppress the DC side midpoint voltage fluctuations. The prediction model of the inverter side current and the DC side midpoint voltage of the LCL-filtered 3-level grid-connected inverter is established under the weak grid. Aiming at the resonance problem of the LCL filter, the MPC-i₁u_c_{_}_f resonance suppression strategy is proposed from the perspective of prediction model, which using the fundamental frequency component of the capacitor voltage and eliminating the influence of resonance components on the system, and the resonance is suppressed when the inductance of the weak grid changes. Compared with the existing resonance suppression methods under model predictive control, the proposed method reduces the complexity of parameter design and is easy to implement in engineering. The experimental results show that under the weak grid conditions, the proposed method of MPC-i₁u_c_{_}_f can achieve system resonance suppression, and the grid-connected current can be well controlled, while taking into account the neutral voltage balance of the DC side.

Key words: Weak grid, LCL, resonance suppression, mid-point voltage, model predictive control

中图分类号:

TM464

丁金勇, 吕建国, 徐炜基, 孙状. 弱电网下基于模型预测控制的NPC三电平LCL型并网逆变器谐振抑制方法研究^*[J]. 电气工程学报, 2021, 16(2): 190-198.

DING Jinyong, LÜ Jianguo, XU Weiji, SUN Zhuang. Research on Resonance Suppression Method of LCL-filtered NPC 3-level Grid-connected Inverter Based on Model Predictive Control in Weak Grid[J]. Journal of Electrical Engineering, 2021, 16(2): 190-198.

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参考文献 25

[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):1-12,21.
	ZENG Zheng, ZHAO Rongxiang, TANG Shengqing, et al. Review of advanced grid-connected inverters for renewable energy dispersion access[J]. Proceedings of the CSEE, 2013, 33(24):1-12,21.
[2]	高家元, 赵晋斌, 陈晓博, 等. 电压并网逆变器的功率控制与设计[J]. 中国电机工程学报, 2018, 38(6):11,1788-1799.
	GAO Jiayuan, ZHAO Jinbin, CHEN Xiaobo, et al. Power control and design of voltage-controlled grid-connected inverter[J]. Proceedings of the CSEE, 2018, 38(6):11,1788-1799.
[3]	吴恒, 阮新波, 杨东升. 弱电网条件下锁相环对LCL型并网逆变器稳定性的影响研究及锁相环参数设计[J]. 中国电机工程学报, 2014, 34(30):5259-5268.
	WU Heng, RUAN Xinbo, YANG Dongsheng. Study on the influence of phase-locked loop on the stability of LCL grid-connected inverter under weak grid conditions and design of phase-locked loop parameters[J]. Proceedings of the CSEE, 2014, 34(30):5259-5268.
[4]	杨东升, 阮新波, 吴恒. 提高LCL型并网逆变器对弱电网适应能力的虚拟阻抗方法[J]. 中国电机工程学报, 2014, 34(15):2327-2335.
	YANG Dongsheng, RUAN Xinbo, WU Heng. Virtual impedance method to improve the adaptability of LCL grid-connected inverter to weak grid[J]. Proceedings of the CSEE, 2014, 34(15):2327-2335.
[5]	许津铭, 谢少军, 唐婷. 弱电网下LCL滤波并网逆变器自适应电流控制[J]. 中国电机工程学报, 2014, 34(24):4031-4039.
	XU Jinming, XIE Shaojun, TANG Ting. Adaptive current control of LCL filter grid-connected inverter in weak grid[J]. Proceedings of the CSEE, 2014, 34(24):4031-4039.
[6]	王洋, 程志江, 李永东. 三电平并网逆变器的低开关频率模型预测控制[J]. 可再生能源, 2018, 36(10):1473-1478.
	WANG Yang, CHENG Zhijiang, LI Yongdong. Low switching frequency model predictive control of three-level grid-connected inverter[J]. Renewable Energy, 2018, 36(10):1473-1478.
[7]	SCOLTOCK J, GEYER T, MADAWALA U K. Model predictive direct power control for grid-connected NPC converters[J]. IEEE Transactions on Industrial Electronics, 2015, 99:1-10.
[8]	SE B F, VAHEDI H, KANAAN H Y, et al. Design and implementation of space vector modulation-based sliding mode control for grid-connected 3l-NPC inverter[J]. IEEE Transactions on Industrial Electronics, 2016, 63(12):7854-7863. doi: 10.1109/TIE.2016.2563381
[9]	杨勇, 樊明迪, 谢门喜, 等. 三电平三相逆变器快速有限控制集模型预测控制方法[J]. 电机与控制学报, 2016, 20(8):83-91.
	YANG Yong, FAN Mingdi, XIE Menxi, et al. Model predictive control method for fast finite control set of three-level three-phase inverter[J]. Journal of Electric Machines and Control, 2016, 20(8):83-91.
[10]	金楠, 胡石阳, 崔光照, 等. 光伏并网逆变器有限状态模型预测电流控制[J]. 中国电机工程学报, 2015, 35(S1):190-196.
	JIN Nan, HU Shiyang, CUI Guangzhao, et al. Predictive current control of photovoltaic grid-connected inverter with finite state model[J]. Proceedings of the CSEE, 2015, 35(S1):190-196.
[11]	陈燕东, 罗安, 彭自强, 等. 光伏并网发电与无功补偿的鲁棒预测控制[J]. 电工技术学报, 2013, 28(11):239-246,253.
	CHEN Yandong, LUO An, PENG Ziqiang, et al. Robust predictive control of photovoltaic grid-connected power generation and reactive power compensation[J]. Transactions of China Electrotechnical Society, 2013, 28(11):239-246,253.
[12]	魏玉春, 夏长亮, 刘涛, 等. 两电机转矩同步系统有限集模型预测控制[J]. 电工技术学报, 2016, 31(19):115-122.
	WEI Yuchun, XIA Changliang, LIU Tao, et al. The finite set model predictive control of two-motor torque synchronous system[J]. Transactions of China Electrotechnical Society, 2016, 31(19):115-122.
[13]	闫涵, 吕建国, 丁金勇, 等. 非理想电网下NPC三电平逆变器多目标模型预测控制方法研究[J]. 电气工程学报, 2019, 14(3):23-32.
	YAN Han, LÜ Jianguo, DING Jinyong, et al. Research on the multi-target grid-connected control method of NPC three-level inverter based on model prediction under non-ideal grid conditions[J]. Electrical Engineering Journal, 2019, 14(3):23-32.
[14]	KOURO S, CORTES P, VARGAS R, et al. Model predictive control-a simple and powerful method to control power converters[J]. IEEE Transactions on Industrial Electronics, 2009, 56(6):1826-1838. doi: 10.1109/TIE.2008.2008349
[15]	CORTES P, KAZMIERKOWSKI M P, KENNEL R M, et al. Predictive control in power electronics and drives[J]. IEEE Transactions on Industrial Electronics, 2008, 55(12):4312-4324. doi: 10.1109/TIE.2008.2007480
[16]	王萌, 施艳艳, 沈明辉, 等. 三相电压型整流器模型电压预测控制[J]. 电工技术学报, 2015, 30(16):49-55.
	WANG Meng, SHI Yanyan, SHEN Minghui, et al. Model voltage prediction control of three-phase voltage-type rectifier[J]. Transactions of China Electrotechnical Society, 2015, 30(16):49-55.
[17]	WU Weimin, HE Yuanbin, TANG Tianhao, et al. A new design method for the passive damped LCL and LLCL filter-based single-phase grid-tied inverter[J]. IEEE Transactions on Industrial Electronics, 2013, 60(10):4339-4350. doi: 10.1109/TIE.2012.2217725
[18]	许德志, 汪飞, 阮毅. LCL、LLCL和LLCCL滤波器无源阻尼分析[J]. 中国电机工程学报, 2015, 35(18):4726-4736.
	XU Dezhi, WANG Fei, RUAN Yi. Passive damping of LCL,LLCL and LLCCL filters[J]. Proceedings of the CSEE, 2015, 35(18):4726-4736.
[19]	BAO C, RUAN X, WANG X, et al. Step-by-step controller design for LCL-type grid-connected inverter with capacitor current feedback active-damping[J]. IEEE Transactions on Power Electronics, 2014, 29(3):1239-1253. doi: 10.1109/TPEL.2013.2262378
[20]	HE J, LI Y W. Generalized closed-loop control schemes with embedded virtual impedances for voltage source converters with LC or LCL filters[J]. IEEE Transactions on Power Electronics, 2012, 27(4):1850-1861. doi: 10.1109/TPEL.2011.2168427
[21]	于文倩, 同向前, 燕聪, 等. 提高弱电网下LCL型并网逆变器稳定性的改进电网电压前馈策略[J]. 电气工程学报, 2019, 14(2):79-85.
	YU Wenqian, TONG Xiangqian, YAN Cong, et al. An improved grid voltage feedforward strategy for LCL-type grid-connected inverters in weak grid[J]. Journal of Electrical Engineering, 2019, 14(2):79-85.
[22]	LI W, RUAN X, PAN D, et al. Full-feedforward schemes of grid voltages for a three-phase LCL-type grid-connected inverter[J]. IEEE Transactions on Industrial Electronics, 2013, 60(6):2237-2250. doi: 10.1109/TIE.2012.2193864
[23]	ZHANG X, WANG Y, YU C, et al. Hysteresis model predictive control for high-power grid-connected inverters with output LCL filter[J]. IEEE Transactions on Industrial Electronics, 2016, 63(1):246-256. doi: 10.1109/TIE.2015.2477060
[24]	FALKOWSKI P, SIKORSKI A. Finite control set model predictive control for grid-connected AC-DC converters with LCL filter[J]. IEEE Transactions on Industrial Electronics, 2018, 65(4):2844-2852. doi: 10.1109/TIE.2017.2750627
[25]	LÜ J, HU W, WU F, et al. Variable modulation offset SPWM control to balance the neutral-point voltage for three-level inverters[J]. IEEE Transactions on Power Electronics, 2015, 30(12):7181-7192. doi: 10.1109/TPEL.2015.2392106

参数	数值
电网电压e_g/V	80
电网基频f/Hz	50
直流侧电压V_dc/V	220
直流侧电容C₁(=C₂)/µF	150
采样周期T_s/µs	50
逆变器侧电感L₁/mH	3
电感L₁寄生电阻R₁/Ω	0.5
交流侧电容C_f/µF	20
网侧电感L₂/mH	1.5