Application of wavelet network for induction motor in direct torque control system operating at low speed
-
摘要: 针对传统的异步电动机直接转矩控制系统低速运行时存在较大转矩脉动的问题,详细分析了定子电阻变化对系统控制性能的影响,提出了基于小波网络的定子电阻辨识方法.将定子电流的误差和定子电流误差的变化量作为小波网络的输入,网络输出为定子电阻误差的动态估计值;综合应用递推正交最小二乘法与改进的Givens变换训练小波网络参数,利用小波网络良好的时频局部特性可以准确的观测出定子磁链和转矩,优化了逆变器的控制策略.仿真结果对比表明该方法可以有效得改善电动机的低速运行性能,优于采用BP(Backward Propagation)神经网络的方法.Abstract: To improve the low-speed dynamic performance of induction motor DTC(direct torque control), a novel method of stator resistance identification based on WN(wavelet network) was presented. The inputs of the WN were the current error and the change in the current error and the output of the WN was the stator resistance error. The synthesized method of ROLSA(recursive orthogonal least squares algorithm) and improved Givens transform was used to fulfill the network structure and parameter identification. By the use of wavelet transform that accurately localized the characteristics of a signal both in the time and frequency domains, the occurring instants of the stator resistance change could be identified by the multi-scale representation of the signal. Once the instants were detected, the accurate stator flux vector and electromagnetic torque were acquired by the parameter estimator, which made the DTC applicable in the low region, and the inverter control strategy was optimized. The simulation results show that the proposed method can efficiently reduce the torque ripple and current ripple, and is superior to the BP(backward propagation) neural network.
-
[1] 赵争鸣,袁立强,孟朔,等.通用变频器矢量控制与直接转矩控制特性比较[J].电工技术学报,2004,19(4):81-84 Zhao Zhengming,Yuan Liqiang,Meng Shuo,et al. Comparison of vector control and direct torque control for general inverters[J]. Transactions of China Electrotechnical Society,2004,19(4):81-84(in Chinese) [2] 王萍,李斌,黄瑞祥,等.基于神经网络的无速度传感器直接转矩控制系统的研究[J].电工技术学报,2003,18(2):5-8 Wang Ping,Li Bin,Huang Ruixiang,et al. Study of speed-sensorless direct torque control system based on neural-network[J]. Transactions of China Electrotechnical Society,2003,18(2):5-8(in Chinese) [3] 王晓东,石海峰.基于自适应线性神经元速度观测器在直接转矩控制系统中的应用[J].电工技术学报,2003,18(1):27-32 Wang Xiaodong,Shi Haifeng. Application of direct torque control system based on speed observer of ADALINE[J]. Transactions of China Electrotechnical Society,2003,18(1):27-32(in Chinese) [4] 张春,郭兴众.模糊直接转矩控制系统的设计与仿真研究[J].电子科技大学学报,2004,33(5):582-585 Zhang Chun,Guo Xingzhong. Design and simulation of fuzzy direct torque control system[J]. Journal of UEST of China,2004,33(5):582-585(in Chinese) [5] Stephen A Billings,Hua Liangwei. A new class of wavelet networks for nonlinear system identification[J]. IEEE Transactions on Neural Network,2005,16(4):862-874 [6] 陈硕,迁峰男,山田英二. 感应电机无速度传感器矢量控制系统的定子电阻在线辨识[J].中国电机工程学报,2003,23(2):88-92 Chen Shuo,Tsuji Mineo,Yamada Eiji.On-line identification of stator resistance for sensorless vector control system of induction motors[J]. Proceedings of the CSEE,2003,23(2):88-92(in Chinese) [7] Chen S. Nonlinear times series modeling and prediction using Gaussian RBF network with enhanced clustering and RLS learning[J]. Inst Elect Electron Lett,1995,31(2):117-118 [8] Barry G J,Ding L Y. Selecting radial basis function network centers with recursive orthogonal least squares training[J]. IEEE Transactions on Neural Networks,2000,11(2):306-314
点击查看大图
计量
- 文章访问数: 3481
- HTML全文浏览量: 87
- PDF下载量: 798
- 被引次数: 0