Two-Degree-of-Freedom Internal Model Control Of Two Motor System Based On Neural Network Generalized Inverse

Accompanied by the development of modern industry,multi-motor variable frequency speed-regulating system is widely applied in factory yield,such as,textile, metallurgy,machine,paper,steel rolling,and so on.Realization of high control performance of these systems can improve product quality and productivity.But these kind of systems belong to a multi-variable,high coupling control systems.How to gain great control performance has become an key issue in modern electrical driver area.With the financial aid of National Nature Science Fund(60874014),China Ministry of Education Fund(20050299009) and Natural Science Fund of Jiangsu Province(BK2007094),focusing on a two-motor variable frequency speed-regulating system composed of two AC induction motors and inverters,two-degree-of-freedom internal model control(2-DOF IMC) method based on neural network generalized inverse was proposed.Firstly,the generalized reversibility of this two-motor system working on vector control mode was testified.On the basis of reversibility analysis of original system, the generalized inverse model approximated by the dynamical BP neural network was cascaded with the original system.Secondly,the principle and realized step of internal model control were introduced.Due to the disadvantages of common structure of internal model control,a modified two-degree-of-freedom internal model control method was proposed,which benefits the improvement of control performance.Thirdly,based on MATLAB,the model of this two-motor variable frequency system was constructed by S-FUNCTION,and then the feasibility of two-degree-of-freedom internal model control method based on neural network generalized inverse was testified by simulation.Finally,based on S7-300 PLC,the neural network generalized inverse control system was constructed in PLC,and then both the open loop and close loop characteristics of control system were studied.The results demonstrate that the generalized inverse can transform the MIMO nonlinear system into a number of SISO linear subsystems with open-loop stability,and then benefits the integration of this system.Morever,the decoupling control of the system can be realized successfully and the high control performance can be ensured when the system has changeable load.Meanwhile,the control method proposed in the paper is feasible and can be applied in many industrial control environments.