Optimization of Energy Management System for Fuel-Cell/Battery Hybrid Power in Unmanned Aerial Vehicle

Fuel-cell can be a competitive energy device in the future due to the features of zero emission and high efficiency. Generally, fuel-cell will be used with other energy storage devices because of its slow dynamic response. This paper presents an optimized energy management system for fuel-cell/battery hybrid power unmanned aerial vehicle (UAV). The fuel-cell/battery hybrid system consists of fuel-cells, lithium-ion batteries, along with associated dc/dc converters. Energy management systems are used in order to distribute demand power to power sources (fuel-cell and lithium-ion batteries). State-machine strategy is proposed because of limit calculated ability of UAV and easy for engineering implementation. This paper proposed corresponding power control method for fuel-cell and lithium-ion batteries. In order to minimize the weight of hybrid power system, we take the maximum output power of fuel cell as the input variable, establish the weight model of fuel cells and batteries, found the optimal sizing of FC/BAT. This hybrid power system simulation model has been built on Simulink. The energy management strategies have been tested in a full flight load profile. Results of simulation verified that energy management could distribute demand power reasonable and maintain voltage of DC-bus stable.