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Research On Energy Recovery Technology Of Metro Hybrid Regenerative Braking

Posted on:2020-04-30Degree:MasterType:Thesis
Country:ChinaCandidate:S R ZhongFull Text:PDF
GTID:2392330620451022Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
With the rapid development of China's economy and urbanization,traffic congestion and environmental pollution have gradually emerged in cities,and have become one of the factors restricting the further development of cities.As the backbone of traffic in large cities,Metro has the advantages of green safety,convenience,punctuality and large traffic volume.It plays an irreplaceable role in alleviating urban traffic pressure and improving urban traffic efficiency.Because of the short distance between metro stations and frequent start-up and braking of Metro stations,abundant and considerable feedback energy will be generated in the process of Metro braking.If the braking energy can not be absorbed,it will cause energy waste and increase the DC bus voltage.The traditional energy-absorbing absorption scheme uses electric resistance to consume the subway feedback energy in the form of resistance heating.It not only does not meet the current concept of energy saving and emission reduction,but also needs to be equipped with a corresponding cooling system,which not only occupies the space of the subway but also increases the operational burden of the subway.At present,most of absorption schemes are based on resistance plus super-capacitor or resistance plus energy feedbak system.However,due to the low energy density of super-capacitor and the weak energy resistance of energy feedback system against power shock,it is often necessary to equip super-capacitor or energy feedback system with large capacity and volume,low economy,and the existence of brake resistance weakens significance of regenerative braking.Therefore,it is of great practical significance and practical value to study a new energy absorption scheme that meets the requirements of sustainable energy utilization and green development and meets the power and energy characteristics of Metro braking.This paper mainly studies the regenerative braking energy absorption scheme of the combined system with super-capacitor and low voltage energy feed.The regenerative braking energy feedback model of Metro is built by MATLAB/Simulink platform.The 24-pulse uncontrolled rectifier is used in the metro traction power supply system.The Metro locomotive adopts the parametric model of type A locomotive in the form of 6-drive-2 towing group,and the traction motor adopts vector control method;the super-capacitor energy storage device and the low-voltage energy feedback system are parallel connected on the DC bus of thetraction network,and the traditional control method adopts the voltage-current double closed-loop control strategy,which can achieve the purpose of stabilizing DC bus voltage of traction network.,but it can not effectively control the distribution of the feedback energy between the super-capacitor and the energy feedback system.In this paper,a power-current double closed-loop control strategy is proposed to achieve the desired energy distribution by tracking the power.In order to optimize the utilization efficiency of the energy converter system and the utilization efficiency of the super-capacitor capacity,this paper proposes a scheme for optimally distributing the feedback energy absorbed by the energy storage device and the energy feedback system by dynamically adjusting the maximum absorbed power of the energy feedback system.According to the curve of the subway braking power and the basic laws of kinematics,the relationship between the braking time and the initial braking speed is deduced.On the basis of considering the difference of power characteristics and the difference of energy recovery cost per unit,the optimal energy distribution objective function of the metro braking is established,and the maximum absorbed power of the energy feedback system is obtained through mathematical analysis.In the subway braking,the maximum absorbed power of the energy feedback system is dynamically adjusted by sampling the peak power of the subway to achieve the best feedback energy absorption effect.
Keywords/Search Tags:Subway, Regenerative braking, Supercapacitor, Low-voltage energy feedback system, Optimal energy distribution strategy
PDF Full Text Request
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