Application of Energy Storage Technologies for Electric Railway Vehicles—Examples with Hybrid Electric Railway Vehicles

Abstract

Regenerative braking of railway electric vehicles is effective when other powering vehicles, in other words electrical load, exist near the regenerating train on the same electrified line. So, at early mornings and late nights, or in the low-density district lines, regeneration cancellation phenomenon often occurs and the regenerative brake force cannot be operated in accordance with the commanded value. The new high-performance energy storage devices tackle the issues of energy storage and reuse technologies for on-ground and on-vehicle situations. A hybrid energy source is one effective solution. In this paper, the effective use of regenerating braking and the expected electricity storage technology in future for further energy conservation in the electric railway field will be outlined, with actual examples. 

Reduction of Reactor Weight by Using Electromagnetic Coupling

“…The energy storage system onboard train is necessary to the chopper system for charging and discharging. For example, actual vehicles with onboard energy storage systems use a chopper to convert DC 1,500 V/600 V into DC 750 V [1]. This paper estimates the effect of electromagnetic coupling when…”

“…6, are used on the chopper systems of electric vehicle developed by RTRI [1]. It has three phases and choppers operate with equal-phase switching.…”

“…However, energy storage devices on board trains must be accompanied by on-board DC-DC converter systems. For example, the "Hi-tram," developed by RTRI, has two three-phase current reversible choppers [1]. Onboard DC-DC converter systems increase vehicle weight.…”

Reducing DMU fuel consumption by means of hybrid energy storage

“…In contrast electric vehicles typically recuperate 12 to 42% of line energy (depending on type of service, driving style, network characteristics, vehicle type…) [5,12,13]. One option to recuperate braking energy in DMUs is the use of onboard energy storages [14][15][16][17]. Measurements done on diesel electric multiple units with two 200 kW energy storages showed a fuel consumption reduction of more than 8% during driving [18].…”

A Dual-Stage Modeling and Optimization Framework for Wayside Energy Storage in Electric Rail Transit Systems

“…Another literature highlights the use of SCs in the metropolitan railway systems of Colombia and sheds light on the dependence of regenerative braking energy recovery on train scheduling [5]. The performance of different types of ESSs in serving various functionalities, such as voltage quality, emergency power supply, and load levelling, when deployed in the rail transportation system of Japan has been demonstrated in [6,7]. Other similar demonstration projects comprise the use of a sodium-sulphide battery system for Long Island, an SC system for Madrid de Metro, and a flywheel for London Underground, which have been reviewed for effectiveness and return on investment [4,8].…”