Research On Control Strategy Of UAV Composite Power

In recent years,drones have taken on increasingly important roles in various aspects,including: power systems,agriculture,exploration,military,etc.In the power system,the use of drones instead of manual line patrol can improve the efficiency of patrol inspection and reduce the labor intensity of workers.At present,UAVs are mainly powered by lithium batteries and have continuous high current output during flight.The significant advantages of lithium batteries are high energy density and stable output,but its disadvantages are low power density and high current output will reduce the service life of lithium batteries.In this paper,the composite power supply is applied to drone power supply and its control Research strategies to improve the life of lithium batteries.Firstly,this article analyzes the composite power supply,including lithium battery,super capacitor,bidirectional DC/DC,establishes an equivalent model,selects super capacitor and bidirectional DC/DC in series,and then connects in parallel with the lithium battery as the power supply method of the UAV power supply.Analyze the control method of the converter and build a simulation model.Based on the characteristics of the UAV motor,the motor speed control strategy is designed,and the control method adopts the traditional PI control method.Secondly,the UAV's composite power system is designed.Through the analysis of the UAV's demand,the main functions and technical indicators that the UAV's composite power system should meet are determined.According to the power required by the UAV in flight,the lithium battery and The type and number of super capacitors,the overall scheme and software design of the composite power system.For the power management module of the composite power supply system,two control strategies are studied.One is the logic threshold control strategy,which uses the average power of the drone as the limit to distribute lithium battery and super capacitor power;the other is the fuzzy control strategy,which uses lithium battery charge The power state,the state of charge of the super capacitor,and the power required by the drone are used as a reference to allocate the power of the drone.Finally,build a simulation model in Matlab/Simulink.Simulate the motor under no-load and variable load conditions to verify the motor speed control strategy.The power supply part is simulated,and the power,current,and state of charge of the composite power supply under a single lithium battery and two control strategies are compared and analyzed,proving that the composite power supply is suitable for drones,and the fuzzy control strategy is more effective.The fuzzy control strategy is further verified by simulating the extreme case where the load power increases frequently.The results show that the control strategy is correct.In this paper,the composite power supply is applied to UAV power supply.The control strategy also makes the UAV composite power supply overcome the problems of traditional single lithium battery high current discharge and shorten the life of the lithium battery.It can provide a stable power output for the UAV.To a certain extent,the drone's flight time can also be extended.