An optimized energy management strategy for fuel cell hybrid power system based on maximum efficiency range identification

Abstract

This study proposes an optimized energy management strategy (EMS) based on maximum efficiency range (MER) identification for a fuel cell/battery hybrid sightseeing car. And the aim of this study is to optimize hydrogen consumption of hybrid system and make sure that the power distribution between the fuel cell (FC) system and battery is optimal. FC system has the MER and is also a strongly coupled system. The MER of FC system will move with the change of operating conditions, and consequently, a parameter identification technique is needed to estimate the boundary powers of MER. This goal is achieved in this paper by using a forgetting factor recursive least square (FFRLS) online identification approach. Then the sequential quadratic programming (SQP) algorithm is used to solve the majorization problem of equivalent consumption minimum strategy (ECMS) so that the FC system operates as much as possible in the MER, while ensuring that the battery state of charge (SOC) fluctuates within the limited range. This helps to improve the efficiency, performance, and durability of the FC system and reduce the equivalent hydrogen consumption of the battery. A reduce-scale test platform is designed to verify the feasibility of the proposed optimized ECMS (OECMS). In addition, the conventional ECMS and rule-based state machine control (SMC) strategy are utilized in this paper to highlight the advantages of the proposed strategy. The experiment results show that the proposed OECMS helps to improve FC performance and optimize system hydrogen consumption.