Research On Pure Electric Brake Technology Of Urban Rail Train

With the rapid development of the world economy,a sharp increase in urban population and the number of motor vehicles,urban rail train as urban rail transit an important means of transportation,due to its own carrying capacity,speed,and many other advantages zero blocked by people of all ages.Currently,the majority of urban rail train uses electro-pneumatic brake,the inherent differences in the brake characteristics of both electric brake and air brake,leading to the presence of electro-pneumatic brake pad wear,ride comfort and parking Location accuracy are both not ideal and so on.In view of the above problems,the use of pure electric brake parking technology can be better resolved.On the basis of summarizing the research and application of the pure electric brake parking at home and abroad,this thesis mainly studies the braking force control and reliable speed detection of the pure electric brake of urban rail trains.This thesis compares the electro-pneumatic brake technology commonly used in urban rail trains to explain the pure electric brake parking technology.Based on the analysis of the demand for pure electric brake of urban rail train,a new method of deceleration impulse rate control is designed according to the comfort and the evaluation index.and a corresponding deceleration impulse rate control method is designed.Based on the actual situation of Beijing Metro Line 10,the longitudinal force of the actual train is analyzed,the dynamic equation of the train is deduced,the load model of the urban rail train is established and the parameters are verified.The control strategy of pure electric brake based on FOC is studied.According to the principle of steady and dynamic mathematical model of asynchronous motor,the comparison of V/f constant voltage frequency ratio control method and FOC vector control method is carried out.The indirect vector control of the voltage-type rotor is analyzed in detail.A control strategy of voltage feed-forward decoupling is adopted to improve the control performance of asynchronous motor at low speed.The pure electric brake control model of urban rail trains in full speed range is established,and the influence of different control methods under regenerative brake and reverse brake is simulated.The simulation results show that the vector control FOC control method The superiority of the application in the whole system control of the urban rail train improves the control performance of the low-speed electric brake.The mechanical structure,the principle of speed measurement and the realization of the control system software of the speed sensor are studied.The causes of the speed error and the influence on the control precision are described.The speed sensor signal processing,proposes a method based on the effective velocity curve fitting method of least squares,the least squares fitting order,sampling interval length and calculation predictionpoint with simulation in detail.The urban rail train brake system belongs to the large inertia system and the braking process is afirst-order function.Therefore,the first-order function is used to fit.Due to the limitation of the DSP calculation ability,the sampling interval length should not be too long.According to the actual situation of the whole system construction lag,calculation prediction point should be in a reasonable range.This thesis presents a method to detect the zero velocity from the angle of the number of pulses,which improves the accuracy of urban rail train brake.Experimental verification of the actual speed curve fitting results closer to the train,effectively improve the overall performance of pure electric brake of-urban rail train.Based on the experiment platform of hybrid EMU,the pure electric brake control method proposed in this thesis is verified.The results show that the method can effectively realize the pure electric brake under the low speed of urban rail train.Based on the experimental platform,the pure electric braking control method is verified by experiments.The results show that the method used in this thesis can effectively realize all electric braking.