Model-Free Predictive Voltage Control Strategy for LC-Filtered Voltage Source Inverter
Yin Zheng1, Hu Cungang1, Rui Tao2, Feng Zhuangzhuang1, Lu Geye3
1. School of Electrical Engineering and Automation Anhui University Hefei 230601 China; 2. School of Internet Anhui University Hefei 230601 China; 3. State Key Lab of Security Control and Simulation of Power Systems and Large Scale Generation Equipment Tsinghua University Beijing 100084 China
Abstract：This paper proposes a model-free predictive voltage control strategy for LC-filtered voltage source inverters to solve the problem that the prediction error increases when the parameters of conventional model predictive control are mismatched. The strategy establishes a look-up table based on the double gradients of voltage and current. By calculating and storing the voltage and current gradients under the action of the application vectors at the previous time, combined with the sampling values at the current time, the voltage and current at the future time can be predicted. The state space prediction equation is further reconstructed. The gradient value of the unapplied vector is updated according to the voltage and current gradients under the action of the applied vector. The voltage and current cost functions evaluate and select the optimal vector in the next control period. This method is independent of system parameters and simple, which can eliminate the stagnation of gradient updating in the conventional model-free prediction and improve the output voltage performance. Finally, simulation and experiment verify the effectiveness and superiority of the proposed method. Firstly, the look-up table of the capacitor voltage gradient and the inverter-side current gradient is designed. Based on the gradient information, the voltage and current can be predicted without parameters. Secondly, the proposed method reconstructs the state-space prediction equation to ensure real-time updates of all gradients in each control period, eliminating the stagnation phenomenon of conventional model-free predictive control. In addition, the output voltage quality is further improved using the cost function with two control targets. Finally, the effectiveness of the proposed method is verified by experiments. Simulation results on the voltage-current gradient updating show that the root mean square error (RMSE) of the conventional updating method is 6.91 V, and the RMSE of the proposed model-free predictive voltage control (MFPVC) updating method is 3.66 V, which is 3.25 V lower than that of the conventional updating method. Experimental results on the accurate model parameters show that the proposed method can achieve similar voltage performance with the conventional model predictive voltage control (MPVC). Experimental results on the inaccurate model parameters show that when the controller parameter mismatches the actual parameter, the proposed MFPVC produces smaller prediction errors than the conventional MPVC. Hence, the parameter robustness of the proposed MFPVC can be verified.1231223The following conclusions can be drawn from the simulation and experimental analysis: (1) The proposed method has good parameter robustness. When the parameters change, the output voltage error of the inverter is significantly reduced, the voltage quality is improved, and the voltage performance is similar to that of MPVC under the condition of accurate parameters. (2) This method proposes an advanced voltage and current gradient updating method, which can update the voltage and current gradient under all vectors in real time, eliminate the stagnation phenomenon and the predicted spikes, and further improve the output voltage quality. In future studies, the proposed method can be extended to the LCL filter type VSI, or the voltage ripple can be further reduced by vector combination.
尹政, 胡存刚, 芮涛, 冯壮壮, 陆格野. LC滤波型电压源逆变器无模型预测电压控制策略[J]. 电工技术学报, 2023, 38(14): 3723-3732.
Yin Zheng, Hu Cungang, Rui Tao, Feng Zhuangzhuang, Lu Geye. Model-Free Predictive Voltage Control Strategy for LC-Filtered Voltage Source Inverter. Transactions of China Electrotechnical Society, 2023, 38(14): 3723-3732.
[1] Rocabert J, Luna A, Blaabjerg F, et al.Control of power converters in AC microgrids[J]. IEEE Transa- ctions on Power Electronics, 2012, 27(11): 4734-4749. [2] 郭磊磊, 金楠, 李琰琰, 等. 电压源逆变器虚拟矢量模型预测共模电压抑制方法[J]. 电工技术学报, 2020, 35(4): 839-849. Guo Leilei, Jin Nan, Li Yanyan, et al.Virtual vector based model predictive common-mode voltage redu- ction method for voltage source inverters[J]. Transa- ctions of China Electrotechnical Society, 2020, 35(4): 839-849. [3] 柳志飞, 杜贵平, 杜发达. 有限集模型预测控制在电力电子系统中的研究现状和发展趋势[J]. 电工技术学报, 2017, 32(22): 58-69. Liu Zhifei, Du Guiping, Du Fada.Research status and development trend of finite control set model predi- ctive control in power electronics[J]. Transactions of China Electrotechnical Society, 2017, 32(22): 58-69. [4] 郭磊磊, 金楠, 李琰琰, 等. 并网逆变器无电网电压传感器模型预测控制[J]. 电工技术学报, 2020, 35(12): 108-114. Guo Leilei, Jin Nan, Li Yanyan, et al.Grid voltage sensorless model predictive control for grid- connected inverters[J]. Transactions of China Electro- technical Society, 2020, 35(12): 108-114. [5] 李伟, 张勇军, 肖雄. 实时电感辨识的模型预测并网逆变器控制方法[J]. 电工技术学报, 2018, 33(15): 3450-3460. Li Wei, Zhang Yongjun, Xiao Xiong.The model predictive grid-connected inverter control method based on real-time inductance identification[J]. Transactions of China Electrotechnical Society, 2018, 33(15): 3450-3460. [6] Cortes P, Ortiz G, Yuz J I, et al.Model predictive control of an inverter with output $LC$ filter for UPS applications[J]. IEEE Transactions on Industrial Electronics, 2009, 56(6): 1875-1883. [7] Yaramasu V, Rivera M, Narimani M, et al.Model predictive approach for a simple and effective load voltage control of four-leg inverter with an output LC filter[J]. IEEE Transactions on Industrial Electronics, 2014, 61(10): 5259-5270. [8] Dragičević T.Model predictive control of power converters for robust and fast operation of AC microgrids[J]. IEEE Transactions on Power Elec- tronics, 2018, 33(7): 6304-6317. [9] Zheng Changming, Dragičević T, Majmunović B, et al.Constrained modulated model-predictive control of an LC-filtered voltage-source converter[J]. IEEE Transactions on Power Electronics, 2020, 35(2): 1967-1977. [10] Zhang Yongchang, Jiang Tao, Jiao Jian.Model-free predictive current control of a DFIG using an ultra- local model for grid synchronization and power regu- lation[J]. IEEE Transactions on Energy Conversion, 2020, 35(4): 2269-2280. [11] 芮涛, 尹政, 汪凤翔, 等. 基于双矢量的并网逆变器无模型预测电流控制策略[J]. 电工技术学报, 2023, DOI: 10.19595/j.cnki.1000-6753.tces.221461. Rui Tao, Yin Zheng, Wang Fengxiang, et al.Model- free predictive current control strategy of grid- connected inverter based on double-vector[J]. Transa- ctions of China Electrotechnical Society, 2023,DOI: 10.19595/j.cnki.1000-6753.tces.221461. [12] 张永昌, 屈祈延, 杨海涛. 基于空间矢量调制的Vienna整流器无模型预测电流控制[J]. 电工技术学报, 2022, 37(21): 5541-5547. Zhang Yongchang, Qu Qiyan, Yang Haitao.Model free predictive current control of Vienna rectifier based on space vector modulation[J]. Transactions of China Electrotechnical Society, 2022, 37(21): 5541-5547. [13] Heydari R, Young H, Flores-Bahamonde F, et al.Model-free predictive control of grid-forming inver- ters with LCL filters[J]. IEEE Transactions on Power Electronics, 2022, 37(8): 9200-9211. [14] Lin Chengkai, Liu Tianhua, Yu J T, et al.Model-free predictive current control for interior permanent- magnet synchronous motor drives based on current difference detection technique[J]. IEEE Transactions on Industrial Electronics, 2014, 61(2): 667-681. [15] Lin Chengkai, Yu J T, Lai Y S, et al.Improved model-free predictive current control for synchronous reluctance motor drives[J]. IEEE Transactions on Industrial Electronics, 2016, 63(6): 3942-3953. [16] Carlet P G, Tinazzi F, Bolognani S, et al.An effective model-free predictive current control for synchronous reluctance motor drives[J]. IEEE Transactions on Industry Applications, 2019, 55(4): 3781-3790. [17] Hu Cungang, Yin Zheng, Rui Tao, et al.A novel double-voltage-vector model-free predictive current control method for two-level voltage source inver- ters[J]. IEEE Transactions on Industrial Electronics, 2023, 70(6): 5872-5884. [18] Rui Tao, Yin Zheng, Hu Cungang, et al.Modulated model-free predictive current control for voltage source inverters with stagnation elimination and sampling disturbance suppression[J]. IEEE Transa- ctions on Power Electronics, 2023, 38(6): 6996-7008. [19] Yu Feng, Zhou Chenhui, Liu Xing, et al.Model-free predictive current control for three-level inverter-fed IPMSM with an improved current difference updating technique[J]. IEEE Transactions on Energy Con- version, 2021, 36(4): 3334-3343. [20] Agustin C A, Yu J T, Cheng Yushan, et al.Model-free predictive current control for SynRM drives based on optimized modulation of triple-voltage-vector[J]. IEEE Access, 2021, 9: 130472-130483.
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