## 1 Introduction
To achieve better efficiency of a hybrid LF-LRV system, [PERSON] et al. [19; 20] proposed a state machine strategy based on droop control to coordinate multiple power sources following the states of load change. The obtained results confirmed that the proposed algorithm could satisfy the rapid variations of power demand, ensure the steady operation during the most of diving cycle, and enhance overall tramway efficiency. Despite achieving good performance of power distribution, this method remains a drawback of not flexible operation because of switching modes that are usually based on the on/off mechanism to adapt to the particular working conditions. This may cause instability and delay to the system if the order of charge and discharge for ESDs is not appropriate such as power shortage for the hybrid system in the case of a sudden load change. Considered a powerful tool, the fuzzy logic method has been applied to solve the complex issues of the logical process, especially in the power allocation for the hybrid system. Unlike the classical logic algorithm that requires clear knowledge, accurate equations, and exact numeric data of a system, fuzzy logic combines a different way of thinking, which allows complicated systems to be modeled using a higher degree of flexibility based on human knowledge and experience. In the fuel cell hybrid vehicular system, the fuzzy logic-based approach has been applied to develop the power management strategy in many works. [PERSON] et al. [21] employed the fuzzy logic control (FLC)-based EMS, developed based on the rule-based method from the previous work [22], to satisfy the power demand, reduce fuel consumption and maintain storage devices' SOC for excavators. For an electric vehicle application, [PERSON] et al. [23] used FLC to build EMSs for hybrid FC-BAT and FC-BAT-SC configurations to improve the fuel economy of the car and extend the mileage of the journey. In [24], [PERSON] et al. exploited the master-slave model-based FLC strategy for an EMS design to improve the system efficiency and prolong the component lifespan for a renewable hybrid system. [PERSON] et al. constructed a fuzzy-based EMS with a genetic algorithm for a PEMFC integrated with BATs-SCs to improve the hybrid vehicle behaviors [25]. The feasibility of the FLC methods for the PEMFC hybrid system-based transportation applications was investigated in some papers [26; 27; 28; 29; 30; 31; 32]. For the hybrid tramway systems, the use of FLC was first recommended by [PERSON] et al. [33]. In this work, the multi-level Haar-Wavelet transform was incorporated into the structure of the 2-FLC approach to separate the high- and low-frequency features of the power demand. The results indicated that the proposed strategy achieved high efficiency without compromising the stack efficiency of the PEMFC and coordinated the power demand to each power source appropriately. In [34], [PERSON] et al. designed a fuzzy controller for a locomotive system with input variables of load power demand and BAT SOC and output variable of the PEMFC required power. The study indicated that using this controller could not only keep the dynamic response of the PEMFC in the optimal region but also satisfy the dynamic requirements of the hybrid system. Besides, it also maintained the BAT SOC between 0.6 and 0.8 during the various operating conditions or quick changes of load. To guarantee an ideal BAT power in an FC-BAT-SC tramway system, [PERSON] et al. [35] applied the FLC to find out the suitable factor of the BAT. In this strategy, the BAT power, BAT SOC, and SC SOC were input variables while the BAT corrective factor was the output variable. The simulation was implemented with a real driving cycle and the results proved that the suggested strategy not only made a sufficient BAT power to meet sudden and unexpected demand variations but also avoided critical SOC levels of the BAT and SC. Based on the advantages of FLC, [PERSON] et al.