Optimal Sizing Model of the Energy Storage Type Tramway Considering the Integration of on-Board Energy Storage and off-Board Energy Supply

To realize the economical operation of energy storage type tramway system, a novel optimal sizing method considering the on-board energy storage and off-board energy supply is proposed. Based on the operating conditions of tramway system and the energy efficiency of charging stations, a synthetic cost function including the whole life-time cost of on-board energy storage system (OESS) and the cost of energy supply is formulated. Combined with the particle swarm optimization (PSO), the optimal sizing model is established. Furthermore, compared with the existing pure ultracapacitor (UC) system charging at every stop mode, a hybrid energy storage system (HESS) is discussed from the economic point of view. For balancing the size of OESS and the capacity of charging stations, the proposed fuzzy control not only distributes the power, but also regulates the depth of discharge (DOD) of UC system. Finally, by analyzing the actual operation conditions, the calculation results verify the effectiveness of the proposed size optimization. Compared with the pure UC scheme, the synthetic cost reduces 15.6%, and the peak capacity of charging stations decreases 68%. © 2019, Electrical Technology Press Co. Ltd. All right reserved.