Paper Title
Optimal Control of On-Board Supercapacitor for Energy Saving in DC Mass Rapid Transit

Abstract
This article describes how to optimize the control of an on-board supercapacitor for energy saving in DC mass rapid transit by storing braking energy and returning it to the train while accelerating. The installation of supercapacitors on the train required control, and the method provided in the article was piece-wise line-ar state of charge (SOC), which is a voltage control method that changes between energy storage voltage and train voltage. Particle swarm optimization (PSO) and genetic algorithm optimization (GA) are the techniques applied in this article. The optimization of energy saving by regulating supercapacitors is separated into three case studies: the situation where the initial state of charge is 100%, 50%, and 0%, respectively, with the final condition at the end of service remaining 100%. In the case of a 100% initial state of charge, the test system can save around 430 kWh or 6% of the energy distribution, approximately 8 kWh or 10% of the energy loss, and store up to 390 kWh or 46% of the entire energy created by braking. The advantage of onboard supercapacitor can save an annual green-house gas (GHG) emission in the range of 8.62-9.72% or 1745.79 to 1968.032 metric tons CO2/kWh. Keywords - On-Board Energy Storage, Regenerative Energy, Multi-Train, Supercapacitor, Multi-Conductor.