Study On Nonlinear Dynamical Behavior And Chaos Control In Motor Or Generator Networks

Permanent magnet synchronous motor(PMSM)and permanent magnet synchronous generator(PMSG)are two different types of energy conversion devices,which have widely used in industrial production.It was well known that the dynamic models of PMSM and PMSG are multivariable,nonlinear and strongly coupled.Therefore these systems can exhibit chaotic behaviors when their systemic parameters fall into a certain area,which can lead to the instability and the collapse of the systems.With the development of science and technology,the single motor or generator has not been able to meet production requirement.The networks composed by multiple PMSMs or PMSGs can boost efficiency and promote the automation process but the complexity of the structure in motor or generator networks is increased,which will add more factors of threaten the secure and stable operation for the motor or generator systems.So,it is significant to study on nonlinear dynamical behavior and chaos control in motor or generator networks.In this paper,study on control of chaos for complex motor or generator networks is mainly divided into two aspects:the one is focus on synchronization control schemes and the other one is to suppress chaotic phenomenon.The main research work of the dissertation is as follows:(1)We introduce the mathematical models of PMSM and PMSG,and their chaotic phenomena are described when parameters lie within a certain range.Then identical PMSM or PMSG systems are selected as nodes to construct the linearly coupled networks,while the dynamical behaviors for the networks of PMSMs or PMSGs are investigated.(2)Taking the single permanent magnet synchronous generator into account as a network node,and a method of controlling chaos in the generator networks with Watts-Strogatz small-world topology is studied.First,a novel hybrid controller is presented based on feedback control and finite-time stability theory.The control scheme can take the nodes of generator network to be equilibrium point and guarantee generator network to be stable within finite-time,then the sufficient conditions were derived for finite-time chaos suppression of the generator networks by finite-time stability theory.The fast stabilization problem for generator networks can be solved by adjusting the convergence time of chaos control.(3)It is recently found that the critical value of coupling strength for synchronization of uncoupled outer oscillators is decreased by introducing the dynamic relaying,mediated by mismatched inner oscillator.Namely,dynamic relaying units can enhance synchronization between the outer uncoupled systems.Base on this characteristic,the synchronization of chaos in bidirectional complex motor network with Newman-Watts small-world topology can be realized by introducing the dynamic relaying.The mismatched relay nodes are added to the complex motor network,which can reduce the coupling threshold for synchronization of the whole complex motor network and improve the ability of synchronization about overall network.The control law is easy to implement because the relay node is equivalent to the synchronization controller can achieve chaotic synchronization of the motor network.(4)A novel adaptive pinning controller is proposed for chaotic PMSM network with uncertain parameters.The control strategy can track equilibrium point automatically and ensure the stability of chaotic PMSM network by pinning partial nodes.On the basis of Lyapunov stability theory,we obtained suitable adaptive feedback gain and the number of nodes to be pinned.The proposed scheme can realize stability control with low control cost in complex motor networks.