Research On Vector Control Of Linear Induction Motor Based On IPSO-ILADRC Speed Loop

With the development of society,urban rail transit has entered a large-scale construction stage,in which low noise,low pollution and high safety performance of low and medium speed magnetic levitation systems have received widespread attention.At present,the low and medium speed maglev often uses Linear Induction Motor(LIM)as the driving device,but LIM is a high-order,time-varying,strongly coupled complex nonlinear controlled object,and in the operation process,the unknown disturbance will have a certain impact on the control effect.Therefore,the traditional PID vector control method based on the linear model cannot achieve effective control of the system performance.Linear Active Disturbance Rejection Controller(LADRC)can reduce the influence of nonlinearity and disturbance on the tracking effect without relying on the controlled object model,and greatly improve the system stability and disturbance resistance.The author takes LIM as the research object,based on the theory of LADRC,and improves LADRC to make it applicable to linear induction motor vector control system,as follows:Firstly,the author analyzes the working principle and characteristics of LIM,summarizes the unique four kinds of edge-end effects and proposes relevant solutions,then analyzes the LIM electromagnetic field through two-dimensional finite element simulation to verify the influence of dynamic longitudinal edge-end effects on the air-gap magnetic field,and then establishes a dynamic mathematical model of LIM considering edge-end effects according to the T-shaped equivalent circuit.In order to suppress the disturbances generated during the motor operation,the electromagnetic disturbances and load disturbances generated during the train operation are analyzed and studied to provide theoretical support for the subsequent design of the speed loop.Secondly,the speed differential equation containing electromagnetic disturbance and load disturbance is derived from the motor mathematical model,the LADRC speed regulator is designed,and the vector control system with LADRC speed outer loop and PI current inner loop is established.In order to speed up the convergence speed and reduce the observation error,the expansion state observer of the LADRC speed regulator is improved and designed,and its stability analysis is carried out by using Hurwitz theorem.The control effects of the improved LADRC(ILADRC)and LADRC are compared and analyzed through MATLAB simulation experiments,and the simulation results show that the improved LADRC has better performance in terms of dynamic performance,tracking performance,and immunity performance.Again,in order to rectify the three parameters of the improved LADRC,the Particle Swarm Optimization(PSO)algorithm is introduced to perform the optimization,and the traditional PSO has the problems of early convergence and easy to fall into local optimum,which is verified by performance tests,and illustrates that IPSO is better than traditional PSO in terms of convergence speed and optimization-seeking accuracy.The LIM vector control system with IPSO-optimized ILADRC speed loop parameters is then established to realize the parameter tuning of the speed controller.Finally,in order to further verify the effectiveness of the proposed algorithm,a semiphysical simulation experiment platform is built,and the motor control algorithm and motor model are imported into Rapid Control Prototyping(RCP)and Hardware-in-the-loop(HIL)respectively to simulate the real motor The PI,LADRC,ILADRC,and IPSO-ILADRC speed regulators are compared for no-load start-up,no-load speed abrupt change,and uniform speed abrupt load addition.The experimental results show that the IPSO-ILADRC controller has more advantages in terms of immunity,tracking and stability,and provides some reference value for the high performance control method of linear induction motor for rail transportation.