| Electric multi-rotor UAV has been widely used in military and civil fields due to its advantages of convenient operation,high mobility and low cost.However,the short cruise duration has become one of the key factors restricting its application.In this thesis,a design scheme of hybrid power system for fuel cell UAV is proposed.The system consists of PEMFC,lithium-ion battery,multiple-input converter,fuel cell controller,central controller and other components,in which the PEMFC provides the main energy for the long duration of flight;the lithium-ion battery provides the instantaneous high power;the MIC controls the output current of fuel cell and lithium-ion battery;the central controller is responsible for energy scheduling,management and distribution.Firstly,this thesis establishes the overall model of the power system,designs the overall scheme of the system,and determines the main functions and technical indexes of the system based on the requirement analysis,then calculates and analyzes the system configuration according to the weight constraints and power constraints.Secondly,an energy management strategy of hybrid power system for fuel cell UAV is proposed.The shape of fuzzy control membership function is optimized by using neural network.The algorithm is simulated and the results show that the overall performance of fuzzy neural network control algorithm is better than that of the switch control.Thirdly,the system controller is developed.The hardware is designed based on STM32,and the optimized energy management algorithm is implemented on the controller.Finally,a test system is built,and a flight test is performed on the basis of the platform test.The test results show that the hybrid power system can meet the requirements of rapid changing load of UAV,and the full-load cruise duration can reach 60 minutes.The fuel cell works in a high-efficiency range,the charge and discharge status of lithium-ion battery is well,while the equipment works in the best condition. |
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