| With the rapid development of urban rail transit,people's requirements for train operation performance are increasing day by day.The braking performance of train is an important characterization of operation performance.In order to ensure the safe and stable operation of the train and improve the regenerative braking performance of the train,this paper applies the on-board and wayside energy storage system to the urban rail train,and carries out theoretical and experimental research on the failure of regenerative braking,the stability of regenerative braking and the degradation of regenerative braking control performance in low speed zone.Regenerative braking failure will lead to air braking input,affect the stability of braking,and cause a waste of energy.In order to achieve more safe,reliable,economical and green braking,and taking the nonlinear and multi constraint traction power supply system with on-board and wayside energy storage system as the optimization model,this paper proposes a coordinated control strategy which can run online and the effect is close to the global optimization.Based on the off-line global optimization results of genetic algorithm under typical working conditions,the strategy extracts the laws of linear results with single influencing factors,and carries out the secondary mining of laws for the results of nonlinear or multiple influencing factors,so as to transform the complex global optimization problem into a combination of rules and local optimization problems.Aiming at the local optimization problem refined in the process of secondary mining,this paper comprehensively considers the influencing factors such as train power,train position and the state of on-board / wayside energy storage devices,combined with local variational method and power flow analysis,obtains the mathematical relationship between the optimal decision variables and multiple influencing factors,which can be used for on-line solution.Based on the actual line data of Batong line,the effectiveness and superiority of the strategy are verified by simulation and experiment.In the process of regenerative braking,there is voltage oscillation in the traction network,and the addition of on-board / wayside energy storage system will affect the impedance of the original traction power supply system,thus affecting the law of voltage oscillation.In order to explore the influence of the addition of energy storage system on the stability of traction power supply system,this paper uses the small signal analysis method to model and analyze 12 typical train operating conditions,analyzes and compares the influence of different working conditions on stability.Aiming at the problems of difficult parameter adjustment and poor compensation effect of the existing active damping strategy,from the perspective of damping matching,based on the idea of series virtual damping,the optimal damping compensation form is designed theoretically,and the simplified compensation form that can be realized in engineering is obtained by simplification.Considering the differences of the optimal damping forms under different control structures of the energy storage device,six compensation structures are selected,the optimal damping compensation effects under different compensation structures are compared,and a variable structure optimal damping compensation strategy considering the variation of working conditions is proposed,which can achieve the optimal compensation effect under different working conditions.The regenerative braking of urban rail train is mainly realized by the control algorithm of traction motor.At low speed,the decline of output torque and measurement speed accuracy leads to the decline of motor control performance,and electric braking is difficult to be applied in low speed area.In order to improve the accuracy of output torque and speed observation in low speed region,a parallel identification algorithm of speed,stator resistance and rotor resistance is proposed to ensure the stability of low speed braking region.The algorithm is based on Lyapunov's second stability law.Different from the traditional design,which only uses single parameter,this paper uses the coupling relationship between speed and stator resistance to design the adaptive law of the two.Then,small signal injection is used to identify the rotor resistance accurately.Considering that the small signal injection will increase the output torque ripple,this paper designs a ripple elimination link to ensure the stability of the output torque.In order to verify the effectiveness of the proposed algorithm,the power hardware in the loop experimental platform and the traction motor matching platform are built.The power hardware in the loop experimental platform is based on RTLAB and physical energy storage device.It builds a complex system including energy storage device,traction power supply network and train,which can simulate a variety of working conditions in the process of train operation.The proposed coordinated control algorithm of onboard energy storage device and wayside energy storage device,as well as the variable structure damping compensation strategy,have been effectively verified on the platform.The multi parameter on-line identification algorithm is verified on the motor towing platform and successfully applied in the ground joint debugging test.Figures: 161.Tables: 21.References: 121. |
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