Giordano Domenico, Signorino Davide, Gallo Daniele, Brom Helko E van den, Sira Martin
Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy.
Politecnico di Torino, 10129 Torino, Italy.
Sensors (Basel). 2020 Dec 4;20(23):6935. doi: 10.3390/s20236935.
The energy efficiency of transportation is a crucial point for the rail and metro system today. The optimized recovery of the energy provided by the electrical braking can lead to savings of about 10% to 30%. Such figures can be reached by infrastructure measures which allow the recovery of the breaking energy that is not directly consumed by the rail system and dissipated in rheostat resistors. A methodology for the accurate estimate of such energy is valuable for a reliable evaluation of the cost-benefit ratio associated with the infrastructural investment. The energy can be estimated by measuring a braking current flowing in the rheostats. The varying duty-cycle associated with the high dynamic variation, from zero to thousands of amperes, makes the current measurement very challenging. Moreover, the digitization of such waveforms introduces systematic errors that affect the energy estimation. To overcome these issues, this paper proposes a technique to measure the power and energy dissipated by the rheostat of a DC operated train with high accuracy. By means of an accurate model of the electrical braking circuit (chopper and rheostat) and the frequency characterization of the current transducer, a correction coefficient as a function of the duty-cycle is estimated. The method is then applied to data recorded during a measurement campaign performed on-board a 1.5 kV train of Metro de Madrid during normal operation. Using the proposed technique, the estimation of the dissipated braking energy is improved by 20%.
如今，交通运输的能源效率是铁路和地铁系统的关键所在。优化回收电制动提供的能量可节省约10%至30%。通过基础设施措施能够实现这样的节省比例，这些措施可以回收未被铁路系统直接消耗并在变阻器电阻中耗散的制动能量。准确估算此类能量的方法对于可靠评估与基础设施投资相关的成本效益比非常有价值。能量可以通过测量在变阻器中流动的制动电流来估算。从零到数千安培的高动态变化所带来的不同占空比，使得电流测量极具挑战性。此外，此类波形的数字化会引入影响能量估算的系统误差。为克服这些问题，本文提出一种高精度测量直流运行列车变阻器所耗散功率和能量的技术。借助电制动电路（斩波器和变阻器）的精确模型以及电流传感器的频率特性，估算出作为占空比函数的校正系数。然后将该方法应用于在马德里地铁1.5 kV列车正常运行期间进行的测量活动中记录的数据。使用所提出的技术，制动能量耗散的估算精度提高了20%。
