Abstract：Grid-forming（GFM）converters under asymmetric faults generate significant fault currents, where negative-sequence components impair system control. Traditional virtual-impedance-based current suppression alters system-wide equivalent impedance and affects steady-state current, thereby limiting dynamic reactive power support during fault ride-through（FRT). Moreover, conventional methods require additional negative-sequence extraction, increasing complexity. This paper proposes an FRT strategy combining model predictive control（MPC）with a resonant controller. The method suppresses transient currents under both symmetrical and asymmetrical faults through coordinated control, without affecting steady-state performance, enabling faster reactive power response. Under steady state, it achieves flexible control objectives by adjusting negative-sequence voltage references via a multivariable cost function without explicit sequence extraction. Validation on a 3.5 kW grid-connected experimental platform confirms its effectiveness. The system behavior under asymmetrical faults is first analyzed. At the instant of fault occurrence, the voltage difference between the terminal voltage and the grid voltage induces a large fault current, which consists of a decaying DC offset and a steady-state AC component, as derived from a first-order differential equation. Under steady-state fault conditions, positive-and negative-sequence grid voltage components generate negative-sequence current, and their interaction introduces double-frequency oscillations in the output power. To ensure that the voltage reference output by the VSG does not contain negative-sequence components, a notch filter is applied to the feedback power. Based on the DC characteristic of the transient current, a high-pass filter in the synchronous reference frame extracts the transient component, which is then fed back to the positive-sequence capacitor voltage reference through a resonant controller. This transient suppression strategy is effective under both symmetrical and asymmetrical faults. In steady-state operation, this paper sets four control objectives under asymmetric fault conditions: no negative-sequence current; absorb negative-sequence reactive current; constant reactive power; and constant active power. The relationship between the output negative-sequence terminal voltage and the grid voltage is derived. Using the extracted positive-and negative-sequence components of the grid voltage, the corresponding negative-sequence voltage references are computed and then converted into current references. All voltage and current references are incorporated into a unified multivariable cost function in the stationary frame, where the optimal voltage vector is selected to drive the inverter. The proposed method only needs to modify the reference value of the negative-sequence component. It does not need to extract the positive-and negative-sequence components of the feedback signal, thereby simplifying the control structure. Experimental comparisons with a virtual-resistance-based FRT method show that, under an 80% single-phase voltage dip, the proposed strategy achieves a reactive power response time of 40 ms, compared to 70 ms with the virtual-resistance method. During grid restoration, the active power response time is 50 ms, significantly shorter than the 150 ms of the conventional method. Under steady-state testing, the proposed strategy fulfills the four control objectives, as evidenced by improvements in grid current unbalance, negative-sequence reactive current, and deviations in active and reactive power.
蒋涛, 张永昌. 不对称故障下基于模型预测控制和谐振控制器的构网型变流器故障穿越方法[J]. 电工技术学报, 2026, 41(16): 5609-5621.
Jiang Tao, Zhang Yongchang. Fault Ride-Through Method for Grid-Forming Converters Based on Model Predictive Control and Resonant Control Under Asymmetrical Fault. Transactions of China Electrotechnical Society, 2026, 41(16): 5609-5621.
[1] 李亚楼, 赵飞, 樊雪君. 构网型储能及其应用综述[J]. 发电技术, 2025, 46(2): 386-398. Li Yalou, Zhao Fei, Fan Xuejun.Review of grid-forming energy storage and its applications[J]. Power Generation Technology, 2025, 46(2): 386-398. [2] 詹长江, 吴恒, 王雄飞, 等. 构网型变流器稳定性研究综述[J]. 中国电机工程学报, 2023, 43(6): 2339-2358. Zhan Changjiang, Wu Heng, Wang Xiongfei, et al.Review on stability of grid converter[J]. Proceedings of the CSEE, 2023, 43(6): 2339-2358. [3] Liu Jia, Miura Y, Ise T.Comparison of dynamic characteristics between virtual synchronous generator and droop control in inverter-based distributed generators[J]. IEEE Transactions on Power Electro-nics, 2016, 31(5): 3600-3611. [4] 徐菘, 杨博, 刘浩, 等. 一种提高虚拟同步机电流质量的电压-电流级联闭环控制方案[J]. 电工技术学报, 2024, 39(6): 1871-1885. Xu Song, Yang Bo, Liu Hao, et al.A cascaded harmonic voltage and current closed-loop control method to improve the current quality of virtual synchronous generators[J]. Transactions of China Electrotechnical Society, 2024, 39(6): 1871-1885. [5] Hou Xiaochao, Sun Yao, Zhang Xin, et al.Impro-vement of frequency regulation in VSG-based AC microgrid via adaptive virtual inertia[J]. IEEE Transa-ctions on Power Electronics, 2020, 35(2): 1589-1602. [6] Jongudomkarn J, Liu Jia, Ise T.Virtual synchronous generator control with reliable fault ride-through ability: a solution based on finite-set model predictive control[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2020, 8(4): 3811-3824. [7] Zheng Changming, Dragičević T, Blaabjerg F.Model predictive control-based virtual inertia emulator for an islanded alternating current microgrid[J]. IEEE Transactions on Industrial Electronics, 2021, 68(8): 7167-7177. [8] Shuai Zhikang, Huang Wen, Shen Chao, et al.Chara-cteristics and restraining method of fast transient inrush fault currents in synchronverters[J]. IEEE Transactions on Industrial Electronics, 2017, 64(9): 7487-7497. [9] 李建林, 邹菲, 游洪灏, 等. 构网型储能变流器自适应低电压穿越控制策略[J]. 电工技术学报, 2025, 40(9): 2724-2737. Li Jianlin, Zou Fei, You Honghao, et al.Adaptive low-voltage ride-through control strategy of grid-forming energy storage converter[J]. Transactions of China Electrotechnical Society, 2025, 40(9): 2724-2737. [10] 徐海亮, 吴瀚, 李志, 等. 低短路比电网下含负序控制双馈风机稳定性研究的几个关键问题[J]. 电工技术学报, 2021, 36(22): 4688-4702. Xu Hailiang, Wu Han, Li Zhi, et al.Several key issues on stability study of DFIG-based wind turbines with negative sequence control during low short-circuit ratio power grids[J]. Transactions of China Electro-technical Society, 2021, 36(22): 4688-4702. [11] 熊亮雳, 游力, 韩刚, 等. 基于统一不平衡/谐波电压-电流下垂的构网型变流器电能质量控制[J]. 电源学报, 2025, 23(4): 186-199. Xiong Liangli, You Li, Han Gang, et al.Power quality control for grid-forming converters based on unified unbalanced/harmonic voltage-current droop[J]. Journal of Power Supply, 2025, 23(4): 186-199. [12] Schweizer M, Almér S, Pettersson S, et al.Grid-forming vector current control[J]. IEEE Transactions on Power Electronics, 2022, 37(11): 13091-13106. [13] Lin Xinchun, Zheng Yun, Liang Zhigang, et al.The suppression of voltage overshoot and oscillation during the fast recovery process from load short-circuit fault for three-phase stand-alone inverter[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2021, 9(1): 858-871. [14] Mahamedi B, Eskandari M, Fletcher J E, et al.Sequence-based control strategy with current limiting for the fault ride-through of inverter-interfaced dis-tributed generators[J]. IEEE Transactions on Susta-inable Energy, 2020, 11(1): 165-174. [15] Ge Pingjuan, Xiao Fan, Tu Chunming, et al.Transient power angle control for a droop-controlled voltage source converter considering fault current limita-tion[J]. CSEE Journal of Power and Energy Systems, 2025, 11(5): 2283-2292. [16] 贾科, 刘芸, 毕天姝, 等. 基于自适应虚拟阻抗的构网型新能源电源不对称故障穿越控制[J]. 中国电机工程学报, 2025, 45(8): 2946-2956. Jia Ke, Liu Yun, Bi Tianshu, et al.Asymmetric fault ride through of grid-forming control of renewable energy based on adaptive virtual impedance[J]. Proceedings of the CSEE, 2025, 45(8): 2946-2956. [17] Li Zilin, Chan K W, Hu Jiefeng, et al.An adaptive fault ride-through scheme for grid-forming inverters under asymmetrical grid faults[J]. IEEE Transactions on Industrial Electronics, 2022, 69(12): 12912-12923. [18] 沈霞, 黄文, 帅智康. 基于准PR控制的虚拟同步逆变器故障冲击电流快速抑制方法研究[J]. 中国电机工程学报, 2018, 38(16): 4768-4776, 4981. Shen Xia, Huang Wen, Shuai Zhikang.Research of inrush current restraining strategy based on quasi-PR control for synchronverter during grid fault[J]. Pro-ceedings of the CSEE, 2018, 38(16): 4768-4776, 4981. [19] Wang Yichao, Kuang Yulin, Xu Qianming.A current-limiting scheme for voltage-controlled inverter using instantaneous current to generate virtual impedance[J]. IEEE Journal on Emerging and Selected Topics in Circuits and Systems, 2023, 13(2): 524-535. [20] Pouresmaeil M, Sangrody R, Taheri S, et al.Enhancing fault ride through capability of grid-forming virtual synchronous generators using model predictive control[J]. IEEE Journal of Emerging and Selected Topics in Industrial Electronics, 2024, 5(3): 1192-1203. [21] 潘子迅, 杨晓峰, 赵锐, 等. 不平衡电网下虚拟同步机的多模式协调策略[J]. 电工技术学报, 2023, 38(16): 4274-4285. Pan Zixun, Yang Xiaofeng, Zhao Rui, et al.Multi-mode coordination control of virtual synchronous generator under unbalanced power grid[J]. Transa-ctions of China Electrotechnical Society, 2023, 38(16): 4274-4285. [22] 董纪清, 潘佳清, 毛行奎. 自适应正负序复合控制的VSG低电压穿越策略[J]. 电网技术, 2023, 47(2): 815-822. Dong Jiqing, Pan Jiaqing, Mao Xingkui.Low voltage ride-through strategy of VSG based on adaptive positive and negative sequence composite control[J]. Power System Technology, 2023, 47(2): 815-822. [23] 吕立傲, 胡存刚, 芮涛, 等. 基于无模型预测与无参数参考的LC型滤波逆变器三矢量预测控制方法[J]. 电工技术学报, 2025, 40(16): 5306-5316. Lü Li'ao, Hu Cungang, Rui Tao, et al.Model-free prediction and parameter-less reference based on LC-filtered voltage source inverter triple-vector predi-ctive control[J]. Transactions of China Electrote-chnical Society, 2025, 40(16): 5306-5316. [24] Liu Tong, Chen Alian, Gao Feng, et al.Double-loop control strategy with cascaded model predictive control to improve frequency regulation for islanded microgrids[J]. IEEE Transactions on Smart Grid, 2022, 13(5): 3954-3967. [25] 缪惠宇, 梅飞, 张宸宇, 等. 基于虚拟阻抗的虚拟同步整流器三相不平衡控制策略[J]. 电工技术学报, 2019, 34(17): 3622-3630. Miao Huiyu, Mei Fei, Zhang Chenyu, et al.Three phase unbalanced control strategy for virtual syn-chronous rectifier based on virtual impedance[J]. Transactions of China Electrotechnical Society, 2019, 34(17): 3622-3630. [26] 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. [27] 国家市场监督管理总局国家标准化管理委员会. 风电场接入电力系统技术规定第1部分: 陆上风电: GB/T 19963.1—2021[S]. 北京: 中国标准出版社, 2021. [28] Peng Hanting, Zhou Xiaoping, Zhang Lei, et al.A current-limiting method based on two-stage adaptive virtual impedance for improved grid-supporting capa-bility of grid-forming inverters[J]. IEEE Transactions on Power Electronics, 2025, 40(5): 6539-6554.
2026, Vol. 41 
