Modeling of Regenerative Braking Energy for Electric Multiple Units Passing Long Downhill Section

The process of electric multiple units (EMUs) passing long downhill sections is inevitable in the construction of mountain railways. Moreover, huge regenerative braking energy (RBE) will be sent back to the traction network, threatening voltage safety. Due to the lack of accurate vehicle-grid integrated models considering slope parameters in studying the RBE, this article proposes a modeling scheme, taking China railway high-speed 3 (CRH3) EMUs as an example. First, based on the extended dual pulsewidth modulation (PWM) mathematical model, the quantitative formula for calculating the motor braking power of the CRH3 EMUs is established. Moreover, the slope parameters are introduced into the vehicle-grid model via force analysis and regenerative braking power calculation. Then, by substituting the calculated results into the extended dual PWM mathematical model, the target instruction parameters are solved. Next, the accurate electrical characteristics, including catenary voltage, electromagnetic torque, and converter voltage, are simulated to evaluate the voltage safety. Finally, by comparing the simulation and semi-physical experiment results with the experimental data from the Chengdu to Chongqing railway line, the feasibility, validity, and accuracy of the model are verified.