Adaptive Speed Recovery Strategy of Doubly-Fed Induction Generator Based on Variable PI Control Coefficient
Wang Xin, Yang Dejian
Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology Ministry of Education Northeast Electric Power University Jilin 132012 China
Abstract：Doubly-fed induction generator (DFIG) participates in frequency regulation to support the reduced system inertia. After frequency regulation, the rotor speed is lower than the optimal speed. It is necessary to regain the rotor speed, otherwise, the rate of wind energy utilization would be reduced, or stalling of DFIG even be caused. The existing rotor speed recovery methods only unilaterally improved the performance of speed recovery or reduced the size of frequency secondary drop. To address these issues, this paper suggests a variable-coefficient-PI-control speed recovery strategy. Firstly, this paper revealed the influence mechanism of the amount of the active power reduction and the invitation of the recovery strategy on the frequency secondary drop and the speed recovery performance; secondly, a recovery strategy of the DFIG based on fixed-PI-coefficient control was proposed, the reduction output power with “rise after restrain” manner had been preliminarily constructed to speed recovery. Then, to solve the shortcomings of the recovery strategy with fixed-PI-coefficient, this paper established the coupling relationship between rotor speed of the doubly-fed induction generators and PI control coefficients according to different operating conditions, and then constructed an adaptive recovery strategy based on variable-PI-coefficient to ensure the speed recovery performance while suppressing the frequency secondary drop. Finally, power system model with various wind power penetrations and disturbances was modeled based on an EMTP-RV to investigate the effectiveness of the proposed rotor speed recovery strategy. Simulation results on the different speed recovery strategies illustrate that, under the disturbance of 90 MW with the wind power penetration of 20%, since the DFIG directly removed the frequency support control strategy, it caused a sudden power change of 0.116(pu) so as to result in a frequency secondary drop of 49.69 Hz; the DFIG absorbed more kinetic energy during the short period, the rotor speed regained to the initial value at 95 s; when the DFIG used the fixed-coefficient-PI-control speed recovery strategy, the sudden power variation was reduced by 0.082(pu), the frequency secondary nadir was improved by 0.030 Hz, however, the time for the speed recovery was extended to 120 s; the use of variable-coefficient-PI-control speed recovery strategy started speed recovery without sudden power variation, as a result, no frequency secondary drop was caused, the amount of the active power reduction increase leaded to faster speed recovery during the latter period. When the disturbances increased to 150 MW, the variable-PI-coefficient speed recovery strategy could still maintain the better speed recovery performance and avoid secondary frequency drop. In the case of a large disturbance with a high wind penetration level, the frequency secondary drops for the direct rotor speed recovery and fixed-PI-coefficient speed recovery strategy were lower than the first frequency nadir caused by the disturbance, however, the variable-PI-coefficient speed recovery strategy could guarantee the speed recovery performance without causing a second frequency drop. The following conclusions can be drawn from the simulation analysis: (1) In specific cases, the fixed-coefficient-PI-control speed recovery strategy can preliminarily constructed the “rise after restrain” manner of the active power reduction so as to mitigate the size of frequency secondary drop and ensure speed recovery performance by reasonably employing the parameters of PI controller. (2) The proposed variable-coefficient-PI-control speed recovery strategy can achieve the counterbalance between frequency secondary dip and rotor speed recovery performance compared to constant- coefficient-PI-control speed recovery strategy since the reduction output power with “rise after restrain” manner had been constructed to during the rotor speed recovery period.
王鑫, 杨德健. 基于变系数PI控制的双馈风电机组自适应转速恢复策略[J]. 电工技术学报, 2023, 38(15): 4120-4129.
Wang Xin, Yang Dejian. Adaptive Speed Recovery Strategy of Doubly-Fed Induction Generator Based on Variable PI Control Coefficient. Transactions of China Electrotechnical Society, 2023, 38(15): 4120-4129.
[1] 康重庆, 姚良忠. 高比例可再生能源电力系统的关键科学问题与理论研究框架[J]. 电力系统自动化, 2017, 41(9): 2-11. Kang Chongqing, Yao Liangzhong.Key scientific issues and theoretical research framework for power systems with high proportion of renewable energy[J]. Automation of Electric Power Systems, 2017, 41(9): 2-11. [2] 李军徽, 侯涛, 穆钢, 等. 电力市场环境下考虑风电调度和调频极限的储能优化控制[J]. 电工技术学报, 2021, 36(9): 1791-1804. Li Junhui, Hou Tao, Mu Gang, et al.Optimal control strategy for energy storage considering wind farm scheduling plan and modulation frequency limitation under electricity market environment[J]. Transactions of China Electrotechnical Society, 2021, 36(9): 1791-1804. [3] 朱博, 徐攀腾, 刘科, 等. 柔性直流与风电协同的受端系统频率调控方法[J]. 东北电力大学学报, 2021, 41(2): 86-93. Zhu Bo, Xu Panteng, Liu Ke, et al.Frequency control method for receiving end power system by DFIG and VSC-HVDC[J]. Journal of Northeast Electric Power University, 2021, 41(2): 86-93. [4] 王洋, 杜文娟, 王海风. 风电并网系统次同步振荡频率漂移问题[J]. 电工技术学报, 2020, 35(1): 146-157. Wang Yang, Du Wenjuan, Wang Haifeng.Frequency drift of sub-synchronous oscillation in wind turbine generator integrated power system[J]. Transactions of China Electrotechnical Society, 2020, 35(1): 146-157. [5] 颜湘武, 崔森, 常文斐. 考虑储能自适应调节的双馈感应发电机一次调频控制策略[J]. 电工技术学报, 2021, 36(5): 1027-1039. Yan Xiangwu, Cui Sen, Chang Wenfei.Primary frequency regulation control strategy of doubly-fed induction generator considering supercapacitor SOC feedback adaptive adjustment[J]. Transactions of China Electrotechnical Society, 2021, 36(5): 1027-1039. [6] 颜湘武, 孙雪薇, 崔森, 等. 基于转子动能与超级电容器储能的双馈风电机组惯量和一次调频改进控制策略[J]. 电工技术学报, 2021, 36(增刊1): 179-190. Yan Xiangwu, Sun Xuewei, Cui Sen, et al.Improved control strategy for inertia and primary frequency regulation of doubly fed induction generator based on rotor kinetic energy and supercapacitor energy storage[J]. Transactions of China Electrotechnical Society, 2021, 36(S1): 179-190. [7] 颜湘武, 王德胜, 杨琳琳, 等. 直驱风机惯量支撑与一次调频协调控制策略[J]. 电工技术学报, 2021, 36(15): 3282-3292. Yan Xiangwu, Wang Desheng, Yang Linlin, et al.Coordinated control strategy of inertia support and primary frequency regulation of PMSG[J]. Transactions of China Electrotechnical Society, 2021, 36(15): 3282-3292. [8] 国家市场监督管理总局, 国家标准化管理委员会. 风力发电机组电网适应性测试规程: GB/T 36994—2018[S]. 北京: 中国标准出版社, 2018. [9] National Grid. Mandatory frequency response nation al grid [EB/OL].2016. https://www.nationalgrid.com/ sites/default/files/documents/Mandatory%20Frequency%20Response%20Guide%20v1.1.pdf. [10] 单煜, 汪震, 周昌平, 等. 基于分段频率变化率的风电机组一次调频控制策略[J]. 电力系统自动化, 2022, 46(11): 19-26. Shan Yu, Wang Zhen, Zhou Changping, et al.Control strategy of primary frequency regulation for wind turbine based on segmented rate of change of frequency[J]. Automation of Electric Power Systems, 2022, 46(11): 19-26. [11] 兰飞, 潘益丰, 时萌, 等. 双馈风电机组变系数虚拟惯量优化控制[J]. 电力系统自动化, 2019, 43(12): 51-59. Lan Fei, Pan Yifeng, Shi Meng, et al.Optimal variable-coefficient virtual inertia control for DFIG-based wind turbines[J]. Automation of Electric Power Systems, 2019, 43(12): 51-59. [12] Lee J, Jang G, Muljadi E, et al.Stable short-term frequency support using adaptive gains for a DFIG-based wind power plant[J]. IEEE Transactions on Energy Conversion, 2016, 31(3): 1068-1079. [13] 刘辉, 葛俊, 巩宇, 等. 风电场参与电网一次调频最优方案选择与风储协调控制策略研究[J]. 全球能源互联网, 2019, 2(1): 44-52. Liu Hui, Ge Jun, Gong Yu, et al.Optimization scheme selection of wind farm participation in grid primary frequency modulation and study of wind-storage coordination control strategy[J]. Journal of Global Energy Interconnection, 2019, 2(1): 44-52. [14] 蔡国伟, 钟超, 吴刚, 等. 考虑风电机组超速减载与惯量控制的电力系统机组组合策略[J]. 电力系统自动化, 2021, 45(16): 134-142. Cai Guowei, Zhong Chao, Wu Gang, et al.Unit commitment strategy of power system considering overspeed load reduction and inertia control of wind turbine[J]. Automation of Electric Power Systems, 2021, 45(16): 134-142. [15] Tarnowski G C, Kjar P C, Sorensen P E, et al.Variable speed wind turbines capability for temporary over-production[C]//2009 IEEE Power & Energy Society General Meeting, Calgary, AB, Canada, 2009: 1-7. [16] Kheshti M, Ding Lei, Nayeripour M, et al.Active power support of wind turbines for grid frequency events using a reliable power reference scheme[J]. Renewable Energy, 2019, 139: 1241-1254. [17] Conroy J F, Watson R.Frequency response capability of full converter wind turbine generators in comparison to conventional generation[J]. IEEE Transactions on Power Systems, 2008, 23(2): 649-656. [18] 刘璋玮, 刘锋, 梅生伟, 等. 扩张状态观测器在双馈风机虚拟惯量控制转速恢复中的应用[J]. 中国电机工程学报, 2016, 36(5): 1207-1217. Liu Zhangwei, Liu Feng, Mei Shengwei, et al.Application of extended state observer in wind turbines speed recovery after inertia response control[J]. Proceedings of the CSEE, 2016, 36(5): 1207-1217. [19] 乔颖, 郭晓茜, 鲁宗相, 等. 考虑系统频率二次跌落的风电机组辅助调频参数确定方法[J]. 电网技术, 2020, 44(3): 807-815. Qiao Ying, Guo Xiaoqian, Lu Zongxiang, et al.Parameter setting of auxiliary frequency regulation of wind turbines considering secondary frequency drop[J]. Power System Technology, 2020, 44(3): 807-815. [20] 赵晶晶, 李敏, 何欣芹, 等. 基于限转矩控制的风储联合调频控制策略[J]. 电工技术学报, 2019, 34(23): 4982-4990. Zhao Jingjing, Li Min, He Xinqin, et al.Coordinated control strategy of wind power and energy storage in frequency regulation based on torque limit control[J]. Transactions of China Electrotechnical Society, 2019, 34(23): 4982-4990. [21] 劳焕景, 张黎, 宋鹏程, 等. 一种考虑最优状态动态恢复的风电持续调频策略[J]. 电网技术, 2020, 44(12): 4504-4512. Lao Huanjing, Zhang Li, Song Pengcheng, et al.Wind power sustained frequency regulation strategy with dynamic optimized state recovery behavior[J]. Power System Technology, 2020, 44(12): 4504-4512. [22] 劳焕景, 张黎, 赵彤, 等. 考虑分组控制和有序恢复的风电调频策略[J]. 电力系统自动化, 2020, 44(16): 114-120. Lao Huanjing, Zhang Li, Zhao Tong, et al.Frequency regulation strategy for wind power considering grouping control and orderly recovery[J]. Automation of Electric Power Systems, 2020, 44(16): 114-120. [23] Lao Huanjing, Zhang Li, Zhao Tong, et al.Innovated inertia control of DFIG with dynamic rotor speed recovery[J]. CSEE Journal of Power and Energy Systems, 2020, 8(5): 1417-1427. [24] 高峰, 凌新梅, 王伟. 大型风电机组独立变桨控制器PI参数联合整定[J]. 太阳能学报, 2018, 39(2): 307-314. Gao Feng, Ling Xinmei, Wang Wei.PI parameters joint tuning for individual pitch controller of large wind turbine[J]. Acta Energiae Solaris Sinica, 2018, 39(2): 307-314.
2023, Vol. 38 
