Stability of indirect field-oriented control (IFOC) of induction motor drives is greatly influenced by estimated value of rotor time constant.By choosing estimation error of rotor time constant as bifurcation paramete...Stability of indirect field-oriented control (IFOC) of induction motor drives is greatly influenced by estimated value of rotor time constant.By choosing estimation error of rotor time constant as bifurcation parameter,the conditions of generating Hopf bifurcation in IFOC drives are analyzed.Dynamic responses and Lyapunov exponents show that chaos and limit cycles will arise for some ranges of load torque with certain PI speed controller setting.Stable drives are required for conventional applications,but chaotic rotation can promote efficiency or improve dynamic characteristics of drives.Thus,the study may be a guideline for designing a stable system or an oscillating system.展开更多
In this paper, the stability of stochastic Hopfield neural network with distributed parameters is studied. To discuss the stability of systems, the main idea is to integrate the solution to systems in the space variab...In this paper, the stability of stochastic Hopfield neural network with distributed parameters is studied. To discuss the stability of systems, the main idea is to integrate the solution to systems in the space variable. Then, the integration is considered as the solution process of corresponding neural networks described by stochastic ordinary differential equations. A Lyapunov function is constructed and Ito formula is employed to compute the derivative of the mean Lyapunov function along the systems, with respect to the space variable. It is difficult to treat stochastic systems with distributed parameters since there is no corresponding Ito formula for this kind of system. Our method can overcome this difficulty. Till now, the research of stability and stabilization of stochastic neural networks with distributed parameters has not been considered.展开更多
基金This work was supported by the National Natural Science Foundation of China (No,50177009) and Guangdong Natural Science Foundation (No.011652) .
文摘Stability of indirect field-oriented control (IFOC) of induction motor drives is greatly influenced by estimated value of rotor time constant.By choosing estimation error of rotor time constant as bifurcation parameter,the conditions of generating Hopf bifurcation in IFOC drives are analyzed.Dynamic responses and Lyapunov exponents show that chaos and limit cycles will arise for some ranges of load torque with certain PI speed controller setting.Stable drives are required for conventional applications,but chaotic rotation can promote efficiency or improve dynamic characteristics of drives.Thus,the study may be a guideline for designing a stable system or an oscillating system.
文摘In this paper, the stability of stochastic Hopfield neural network with distributed parameters is studied. To discuss the stability of systems, the main idea is to integrate the solution to systems in the space variable. Then, the integration is considered as the solution process of corresponding neural networks described by stochastic ordinary differential equations. A Lyapunov function is constructed and Ito formula is employed to compute the derivative of the mean Lyapunov function along the systems, with respect to the space variable. It is difficult to treat stochastic systems with distributed parameters since there is no corresponding Ito formula for this kind of system. Our method can overcome this difficulty. Till now, the research of stability and stabilization of stochastic neural networks with distributed parameters has not been considered.
