Research on discretization model of induction motor for low switching-to-fundamental frequency ratio traction system
Zhang Qinpei1, Li Jian1, Lu Yang1, Wu Linghao2, Yang Kai1, Sun jiawei3
1. State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology Wuhan 430074 China; 2. Engineering Research Center of Novel Electrical Machines and Special Electromagnetic Equipment,Ministry of Education Wuhan 430074 China; 3. CRRC Dalian R&D Co. Ltd Dalian 116052 China
Abstract:In high power and high speed motor drives, the control system will operate in low switching-to-fundamental frequency ratio condition . The traditional reduced order discrete model cannot be applied to the control system due to the large discretization error. To address this issue, this paper proposes an eigenvalue based discrete model of induction motor, which still has good steady-state accuracy and transient tracking performance under low switching-to-fundamental frequency ratio. At the same time, a quantitative analysis method of discretization error based on Bode diagram is proposed, and the error magnitude of the proposed model and the traditional discretization model in the observation amplitude and phase of magnetic linkage is quantitatively compared. Firstly, the mathematical model of the induction motor is modeled in the continuous domain by means of state space description. The full-rank state matrix is diagonalized through the transformation matrix. The elements on the diagonal of the diagonal matrix are the characteristic roots of the corresponding stator and rotor voltage equations of the induction motor. Then the exact solution of the system matrix can be obtained through the transformation matrix and the diagonal matrix, as a result of which, the eigenvalue based discrete model of induction motor is derived. At the same time, by deducing the z-domain transfer function of flux linkage observation of different discrete models, the Bode diagram is drawn. Taking the Bode diagram of continuous model as the evaluation standard, the error of the traditional discrete model and the proposed discrete model in the magnitude and phase of flux linkage observation is compared. The simulation and experimental results show that in terms of the steady-state observation accuracy, at the electric frequency of about 20 Hz, the observed current of the first-order discretization model has obvious observation error, while the observed current of the eigenvalue based discrete model has small observation error. When the switching-to-fundamental frequency ratio is seven, the observed current of the second-order bilinear model can maintain stability, but the observed current amplitude and phase have large errors, while the observed current of the characteristic root discretization model can well track the actual synchronous sampling current. In terms of dynamic observation accuracy, in the process of speed reduction, the zero-order holder discrete model has a certain amplitude and phase deviation in current observation, whose maximum amplitude deviation is up to 30%, and the deviation disappears after the speed enters the steady state. By comparison, the eigenvalue based discrete model has good performance in both transient and steady speed. The following conclusions can be drawn from the simulation and experimental results: 1) The proposed discrete model of the characteristic root of the induction motor can achieve high-precision rotor flux and stator current observation in the full speed range. When the switching-to-fundamental frequency ratio is as low as five, the observation error of the flux angle is less than 1 °. 2) Compared with the zero-order holder discretization model, the proposed eigenvalue based discrete model has higher current observation accuracy in the process of speed reduction.
张钦培, 李健, 卢阳, 吴凌豪, 杨凯, 孙佳伟. 低载波比牵引系统的感应电机特征根离散化模型研究[J]. 电工技术学报, 0, (): 117-117.
Zhang Qinpei, Li Jian, Lu Yang, Wu Linghao, Yang Kai, Sun jiawei. Research on discretization model of induction motor for low switching-to-fundamental frequency ratio traction system. Transactions of China Electrotechnical Society, 0, (): 117-117.
[1] ODHANO S A, PESCETTO P, AWAN H A A, 等. Parameter Identification and Self-Commissioning in AC Motor Drives: A Technology Status Review[J]. IEEE Transactions on Power Electronics, 2019, 34(4): 3603-3614. [2] ZHAO L, HUANG J, CHEN J, et al.A Parallel Speed and Rotor Time Constant Identification Scheme for Indirect Field Oriented Induction Motor Drives[J]. IEEE Transactions on Power Electronics, 2016, 31(9): 6494-6503. [3] 李婕, 杨淑英, 谢震, 张兴. 基于有效信息迭代快速粒子群优化算法的永磁同步电机参数在线辨识[J]. 电工技术学报, 2022, 37(18): 4604-4613. Li Jie, Yang Shuying, Xie Zhen, Zhang Xing.Online parameter identification of permanent magnet synchronous motor based on fast particle swarm optimization algorithm with effective information iterated[J]. Transactions of China Electrotechnical Society, 2022, 37(18): 4604-4613. [4] 徐伟, 董定昊, 葛健, 李伟业, 林国斌, 刘智成, 袁文烨. 基于在线参数辨识补偿的直线感应电机低开关频率模型预测控制策略[J]. 电工技术学报, 2022, 37(16): 4116-4133. Xu Wei, Dong Dinghao, Ge Jian, et al.Low switching frequency model predictive control strategy based on online parameter identification compensation of linear induction motor for urban rail application[J]. Transactions of China Electrotechnical Society, 2022, 37(16): 4116-4133. [5] 黄科元,周佳新,刘思美,黄守道. 考虑逆变器非线性永磁同步电机高频注入电感辨识方法[J]. 电工技术学报, 2021, 36(08): 1607-1616. Huang Keyuan, Zhou Jiaxin, Liu Simei, Huang Shoudao.Inductance identification method of permanent magnet synchronous motor considering inverter nonlinearity based on high-frequency injection[J]. Transactions of China Electrotechnical Society, 2021, 36(08): 1607-1616. [6] 刘亚静, 段超. 全数字自适应滤波器不同离散结构的性能对比分析[J]. 电工技术学报, 2021, 36(20): 4339-4349. Liu Yajing, Duan Chao.Performance comparison and analysis of all-digital adaptive filter with different discrete methods[J]. Transactions of China Electrotechnical Society, 2021, 36(20): 4339-4349. [7] XU Y, MORITO C, LORENZ R D.Accurate Discrete-Time Modeling for Improved Torque Control Accuracy for Induction Machine Drives at Very Low Sampling-to-Fundamental Frequency Ratios[J]. IEEE Transactions on Transportation Electrification, 2020, 6(2): 668-678. [8] 孙建业, 王志强, 谷鑫, 等. 高速低载波比下永磁同步电机预测电流控制[J]. 中国电机工程学报, 2020, 40(11): 3663-3673. Sun Jianye, Wang Zhiqiang, Gu xin, et al. Predictive current control of PMSM with high speed and low-frequency-ratio[J]. Proceedings of the CSEE, 2020, 40(11): 3663-3673. [9] 李杰, 詹榕, 宋文祥. 感应电机低采样频率的磁链观测器离散化模型研究[J]. 电工技术学报, 2019, 34(15): 3136-3146. Li Jie, Zhan Rong, Song Wenxiang, et al.Improved discrete observer model of induction motor at low sampling frequency[J]. Transactions of China Electrotechnical Society, 2019, 34(15): 3136-3146. [10] 罗慧. 感应电机全阶磁链观测器和转速估算方法研究[D]. 2009. [11] DIAO L, SUN D, DONG K, et al.Optimized Design of Discrete Traction Induction Motor Model at Low-Switching Frequency[J]. IEEE Transactions on Power Electronics, 2013, 28(10): 4803-4810. [12] WANG B, ZHAO Y, YU Y, et al.Speed-Sensorless Induction Machine Control in the Field-Weakening Region Using Discrete Speed-Adaptive Full-Order Observer[J]. IEEE Transactions on Power Electronics, 2016, 31(8): 5759-5773. [13] 李昱, 郭宏, 平朝春, 王晓辉, 张祯滨. 基于电流源变流器的永磁同步电机驱动系统全状态变量预测转矩控制[J]. 电工技术学报, 2021, 36(01): 15-26. Li Yu, Guo Hong, Ping Zhaochun, Wang Xiaohui, Zhang Zhenbin.A full-state variable predictive torque control of current source converter fed permanent magnet synchronous motor drives[J]. Transactions of China Electrotechnical Society, 2021, 36(01): 15-26. [14] HOLTZ J, QUAN J, SCHMITTT G, et al.Design of fast and robust current regulators for high power drives based on complex state variables[J]. 38th IAS Annual Meeting on Conference Record of the Industry Applications Conference, 2003, 3(5): 1388-1397. [15] 国敬, 范涛, 章回炫, 等. 高速低载波比下永磁同步电机电流环稳定性分析[J]. 中国电机工程学报, 2019, 39(24): 7336-7346+7506. Guo Jing, Fan Tao, Zhang Huixuan, Bian Yuanjun, et al. Stability analysis of permanent magnet synchronous motor current loop control at high speed and low carrier ratio[J]. Proceedings of the CSEE, 2019, 39(24): 7336-7346+7506. [16] KIM H, DEGNER M W, GUERRERO J M, 等. Discrete-time current regulator design for AC machine drives[J]. IEEE Transactions on Industry Applications, 2010, 46(4): 1425-1435. [17] JARZEBOWICZ L.Errors of a Linear Current Approximation in High-Speed PMSM Drives[J]. IEEE Transactions on Power Electronics, 2017, 32(11): 8254-8257. [18] JARZEBOWICZ L.Quasi-discrete modelling of PMSM phase currents in drives with low switching-to-fundamental frequency ratio[J]. IET Power Electronics, 2019, 12(12): 3280-3285. [19] DAI S, WANG J B, SUN Z, et al.Deadbeat Predictive Current Control for High-Speed PMSM Drives with Low Switching-to-Fundamental Frequency Ratios[J]. IEEE Transactions on Industrial Electronics, 2021: 1-1 [20] WEST N T, LORENZ R D.Digital implementation of stator and rotor flux-linkage observers and a stator-current observer for deadbeat direct torque control of induction machines[J]. IEEE Transactions on Industry Applications, 2009, 45(2): 729-736. [21] 赵雷廷, 刁利军, 董侃, 等. 基于状态空间拆分重组的牵引异步电机闭环离散全阶转子磁链观测器[J]. 电工技术学报, 2013, 28(10): 103-112. Zhao Leiting, Diao Lijun, Dong Kan, et al.A novel discretized closed-loop full-order rotor flux observer for induction motor based on re-organization of state space[J]. Transactions of China Electrotechnical Society, 2013, 28(10): 103-112. [22] Jean Claude Alacoque.Direct eigen control for induction machines and synchronous motors[M]. United Kingdom: John Wiley&Sons, 2013. [23] 陈杰,蔡涛,张娟. 离散时间控制系统[M]. 北京: 机械工业出版社, 2006.