This work addresses the problem of self-excited vibration,which degrades the stability of the levitation control,decreases the ride comfort,and restricts the construction cost of maglev system.Firstly,a minimum model ...This work addresses the problem of self-excited vibration,which degrades the stability of the levitation control,decreases the ride comfort,and restricts the construction cost of maglev system.Firstly,a minimum model containing a flexible bridge and a single levitation unit is presented.Based on the simplified model,the principle underlying the self-excited vibration is explored.After investigations about the energy transmission between the levitation system and bridge,it is concluded that the increment of modal damping can dissipate the accumulated energy by the bridge and the self-excited vibration may be avoided.To enlarge the equivalent modal damping of bridge,the sky-hooked damper is adopted.Furthermore,to avoid the hardware addition of real sky-hooked damper,considering the fact that the electromagnet itself is an excellent actuator that is capable of providing sufficiently fast and large force acting on the bridge to emulate the influence of the real sky-hooked damper,the technique of the virtual sky-hooked damper is proposed.The principle underlying the virtual sky-hooked damper by electromagnet is explored and the vertical velocity of bridge is estimated.Finally,numerical and experimental results illustrating the stability improvement of the vehicle-bridge interaction system are provided.展开更多
Deregulation of power system industry is a very large complex exercise based on respective national energy strategies and policies. A lot of matters and knowledge need to be studied before the idea of deregulation can...Deregulation of power system industry is a very large complex exercise based on respective national energy strategies and policies. A lot of matters and knowledge need to be studied before the idea of deregulation can be implemented. Theoretically, it is said that deregulation can make a large impact to increase efficiency and encourage the competitiveness among related parties. However, to implement the concept of deregulation to electric power supply is very tough challenge. In deregulation environment, regardless of market structure, to know the transmission usage allocation is vital and very a complex problem. Thus, a lot of algorithms have been proposed to overcome it. This paper intends to solve the transmission usage allocation problem using optimization approach. The optimization tool that will be utilized is Genetic Algorithm （GA）. GA is probabilistic search technique that has its roots in the principle of genetics and strives for survival. In addition, GA is very robust. Since the nonlinear nature of power flow, it is expected that GA can give optimize results that equitable and acceptable. In this paper, 4-bus and Klos-Kerner 11-bus systems are used for analysis studies. Comparison with other method is also given in this paper.展开更多
基金Projects(11302252,11202230) supported by the National Natural Science Foundation of China
文摘This work addresses the problem of self-excited vibration,which degrades the stability of the levitation control,decreases the ride comfort,and restricts the construction cost of maglev system.Firstly,a minimum model containing a flexible bridge and a single levitation unit is presented.Based on the simplified model,the principle underlying the self-excited vibration is explored.After investigations about the energy transmission between the levitation system and bridge,it is concluded that the increment of modal damping can dissipate the accumulated energy by the bridge and the self-excited vibration may be avoided.To enlarge the equivalent modal damping of bridge,the sky-hooked damper is adopted.Furthermore,to avoid the hardware addition of real sky-hooked damper,considering the fact that the electromagnet itself is an excellent actuator that is capable of providing sufficiently fast and large force acting on the bridge to emulate the influence of the real sky-hooked damper,the technique of the virtual sky-hooked damper is proposed.The principle underlying the virtual sky-hooked damper by electromagnet is explored and the vertical velocity of bridge is estimated.Finally,numerical and experimental results illustrating the stability improvement of the vehicle-bridge interaction system are provided.
文摘Deregulation of power system industry is a very large complex exercise based on respective national energy strategies and policies. A lot of matters and knowledge need to be studied before the idea of deregulation can be implemented. Theoretically, it is said that deregulation can make a large impact to increase efficiency and encourage the competitiveness among related parties. However, to implement the concept of deregulation to electric power supply is very tough challenge. In deregulation environment, regardless of market structure, to know the transmission usage allocation is vital and very a complex problem. Thus, a lot of algorithms have been proposed to overcome it. This paper intends to solve the transmission usage allocation problem using optimization approach. The optimization tool that will be utilized is Genetic Algorithm （GA）. GA is probabilistic search technique that has its roots in the principle of genetics and strives for survival. In addition, GA is very robust. Since the nonlinear nature of power flow, it is expected that GA can give optimize results that equitable and acceptable. In this paper, 4-bus and Klos-Kerner 11-bus systems are used for analysis studies. Comparison with other method is also given in this paper.
