Research On Adaptive Backstepping Control For Permanent Magnet Synchronous Motor Chaotic Systems

Permanent magnet synchronous motor (PMSM) has the advantage of the high starting torque, high power density, high torque to inertia ratio, high power factor, high efficiency and simple structure, it has been widely applied in the industry. However, the chaotic characteristics will appear in PMSM under some specific parameters and working conditions. This chaotic behavior will not only affect the system stability, security, and even endanger its load system. Therefore, based on problems of the harm brought by chaos in the system, this thesis mainly study the PMSM chaos generation mechanism and adopt effective methods to suppress or eliminate the chaotic phenomena in the operation of the machine when the PMSM chaos caused motor system instability. Figures(28), references(61).(1) PMSM chaotic mathematical model is established. Based on the mathematical model description on the chaotic phenomena, PMSM chaotic system Hopf bifurcation is studied. PMSM chaotic system in different parameter limit cycle, Hopf bifurcation and chaotic conditions are obtained. Numerical characteristics of chaotic behavior of PMSM system are studied, such as Lyapunov exponent, fractal dimension, power spectrum and Poincare mapping. Finally, the corresponding Matlab simulation Figure is given.(2) The parameter certainty of PMSM chaotic system is researched through the backstepping control method. First of all, the PMSM chaotic system is divided into three subsystems, the new state variable in the subsystem is set to the virtual control input. Then, based on the stability theory of Lyapunov function is constructed corresponding Lyapunov functions and virtual feedback so as to make the subsystem stabilized, until all subsystems design is completed. Thus PMSM chaotic system speed and current controller and sufficient condition for stability of the system are obtained.(3) The parameter uncertainty of PMSM chaotic system is researched by the adaptive control technology, which is combined with the backstepping and adaptive control strategy when load torque is unknown and permanent magnet flux changes in the PMSM chaos system. The speed, current controller and adaptive controller are designed, not only to complete the identification of the unknown parameters, parameter estimation of uniform convergence, but also to achieve the asymptotic tracking of rotational speed and current. Finally, the controlled system converges to a bounded point. Matlab simulation results are given to show that the adaptive controller is valid, the controlled system can quickly track the desired speed and keep it stable, and convergence of the estimated value of unknown parameter is achieved the practical value.