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Study On Control Strategy Of Linear Induction Motor Traction System Based On Backstepping

Posted on:2019-04-08Degree:MasterType:Thesis
Country:ChinaCandidate:J HuangFull Text:PDF
GTID:2382330548475987Subject:Electrical engineering
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Transportation industry is an important index to measure the level of national economy.Whether the economy of country is healthy and perfect can be seen from the current situation of urban traffic.The transportation industry has provided a very important support for the development of the economy of our country.The rail transit is an important way to relieve the increasing traffic pressure in the city.The main part of the whole rail transit is the traction system,and its research and development directly determine the future of the subway system.In the current development of urban transportation,the problems of traditional rail transit technology of rotating induction motor(RIM)are more and more serious,so that linear induction motor(LIM)traction system has entered the sight of people,which will gradually become an important part of urban rail transit because of its low cost,light noise,small vibration amplitude,strong traction capacity,high climbing angle,small curvature radius,small pollution and high safety factor.Based on the above research background,the robust speed control strategy of LIM traction system considering the influence of uncertain model parameters,external load disturbance,unknown nonlinear function caused by incomplete modeling,external environment change and so on is further explored in this paper on the basis of previous research.The main contents of this paper are summarized as follows:Firstly,this paper collates the main structure and characteristics of the LIM traction system,and summarized the research status of the end effect of LIM,and expounded the principle model of LIM.According to the principle of indirect field-oriented control,the mathematical model of LIM traction system based on IFOC is obtained.Two simulation cases using IFOC based on the traditional proportional-integral(PI)controller are given,which verifies the effectiveness of IFOC.However,the control precision of IFOC is not high,which is seriously affected by the change of motor parameters and the end effect.Then,a projection-based adaptive command-filtered backstepping controller(PACBC)is designed based on IFOC to deal with the problem of speed regulation of LIM traction system with the end effect,uncertain model parameters and external load disturbance.Based on the mathematical model of the LIM traction system using IFOC,the controller is designed by the backstepping method step by step.A constrained command filter is used to solve the differential expansion and the controller input saturation in the traditional backstepping,and compensating signals are designed to reduce the effect of the filtering errors caused by the constrained command filter.The adaptive laws are designed to estimate uncertain parameters(unknown total mass of the mover,viscous friction,and external load disturbances)in LIM by Lyapunov stability theory,and a projection operator is introduced to ensure the boundedness of the estimated parameters.Simulation example is given to show that the designed controller can effectively deal with the problem of the end effect,uncertain parameters and external disturbances in the operation of the LIM traction system,which improves the speed regulation performance.Next,an improverd adaptive command-filtered backstepping Control(IACBC)has been designed by summing up the essence of the adaptive law in PACBC which is to compensate the q-axis control current to deal with the model uncertainy caused by the changes in environmental factors,external disturbances and different road conditions in the actual operation of LIM traction system.IACBC avoids the adaptive estimation of all unknown parameters in the controller,simplifies theoretical deduction process,and reduces the number of adaptive parameters,but can also achieve the control objectives,which makes the research more practical.Simulation examples are given to prove the effectiveness of the designed controller when the parameters of the system model are changed by different factors.Finally,a projection-based adaptive command-filtered fuzzy backstepping controller(PACFBC)has been designed to focuses on the problem of the speed control for LIM traction system with the end effect,uncertain system parameters,external load disturbance and unknown nonlinear functions.The fuzzy logic systems(FLS)are used to approximate the unknown nonlinear functions and deal with uncertain parameters in the designed controller.The projection operator introduced in adaptive laws and FLS guarantees the boundedness of estimated functions and the robustness of designed controller against time-varying disturbances and uncertainties.The proposed control approach can guarantee that all response signals in the closed-loop system are bounded by stability analysis.The simulation comparison results show that the designed controller can track the desired speed signal accurately under the condition of the external disturbance,the unknown system model parameters and the unknown nonlinear function.
Keywords/Search Tags:linear induction motor traction system, backstepping, indirect vector control, adaptive control, indirect fuzzy control, constrained control, speed control
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