Application Of Energy Based Control Method On AC Motor

At present,the electric drive technology of AC motor is an important drive mode in modern industrial production,but the AC motor is a high-order,strong coupling and multivariable nonlinear system.The traditional linear control strategy can not effectively solve the input and output independence control and other related problems,especially in some areas with high speed regulation performance requirements,it is difficult to achieve the control requirements.Therefore,scholars have conducted widely and deeply analysis and research on the control of AC motor.Now,the control methods applied to AC motor include nonlinear control method and intelligent control method.The application of these control methods has greatly improved the control performance of the system,but they hardly consider the position control of the system,and rarely consider the control problem of AC motor from the perspective of energy.Therefore,this paper analyzes and studies the dynamic and static performance of the AC motor from the perspective of energy shaping.Firstly,the design method of control law based on energy(Controlled Lagrangians,CL)is introduced.In addition,the main steps,core points,advantages and disadvantages of CL method is introduced,Compared with the Port Controlled Hiltonian with Dissipation(PCHD)control method,the advantage of the CL method is obtained.Then the basic structure and mathematical model of AC motor is introduced,which lays an important foundation for the application of CL method to the control of AC motor.Then,for the characteristics of high order,strong coupling,non-linear and the input space dimension of the system is less than the number of degrees of freedom of the system,The CL method is applied to the control problems of AC asynchronous motor and permanent magnet synchronous motor(PMSM)respectively.According to the expected controlled energy of the system,CL and generalized force are constructed,and the controlled equation of the system is obtained.In order to ensure the matching between the controlled equation and the original equation,the conservative force with the first-order term of velocity is introduced into the generalized force,and the matching condition is obtained.By solving the partial differential equation in the matching condition,the parameter range of the system matching controller can be obtained,and then the specific matching control law of system can be obtained,which can realize the global asymptotic stabilization of the position and speed simultaneously.Next,the positive definite controlled energy function of the system is taken as Lyapunov function to prove the obtained matching control law can make the system globally stable at the expected equilibrium point,and asymptotic stability is proved by using La Salle invariance theorem.Finally,the main contents of this paper are briefly summarized,and it is shown that the robust CL method can be further studied in the future.