Design And Research Of Hybrid Power System Based On Hydrogen Fuel Cell Unmanned Ship

In the environment led by new policies of environmental protection and resource conservation,especially at present in the middle and late stages of the New Crown epidemic,how to quickly recover and develop the economy has become a global hot issue.The new energy led by solar energy and fuel cells is sought after by consumers for its green,non-polluting and renewable characteristics,and its share in the global energy consumption upgrade is increasing.At present,China’s unmanned ship is still powered by a single energy source mainly battery,this topic refers to the practice of domestic hybrid ships.The fuel cell,battery and photovoltaic system are used as the basis to form a hybrid energy source to power the unmanned ship load through a reasonable topology,giving full play to the advantages of different power supply systems and improving the range of the unmanned ship while meeting its navigation requirements.In this thesis the hydrogen fuel cell system,photovoltaic cell system,and battery system that make up the hybrid power system are selected,modeled,and simulated.For the hydrogen fuel cell system with rated output power of 100 W.The variation of the fuel cell output characteristics under different operating conditions is studied.And a solar system consisting of a monocrystalline solar panel rated at 50 W and a lead battery is modeled and simulated to study the state of charging and discharging of the system.In this thesis we analyze the output characteristics of fuel cell and photovoltaic,and design a DC/DC circuit to compose a hybrid power system.In view of the low efficiency and large ripple of the traditional DC/DC circuit,we design a soft switch to improve the traditional DC/DC circuit,realize zero-current start and zero-voltage shutdown of the switching tube,improve the conversion efficiency of the boost circuit,reduce power loss,and reduce the size of ripple.In this thesis we design a modified DC/DC circuit for a hybrid system,design and select components.Design the corresponding sampling circuit,MOS tube driver circuit,linear voltage regulator circuit,relay circuit,etc.,draw into PCB board,patch and make the real thing.Use STM32 as the main control board,write the relevant control program and conduct relevant experiments.Simulation results show that the improved Buck circuit can achieve fast buck and stabilize at about 12 V.The output voltage loss is lower,the gain is higher,the voltage value is increased by about 1.7%,and the ripple of the output voltage is also reduced by about 50% compared to the output voltage ripple of the conventional Buck circuit.The improved Boost circuit steps up the voltage from 8 V to 12 V with lower voltage losses and about 5% higher conversion efficiency.The tracking speed is also faster in relative terms,taking only about 2.5 seconds.The output voltage ripple phenomenon has also been improved.Finally,the unmanned boat hybrid system was tested and the results showed that the load voltage is about 12 V and the load power is between 75 W and 125 W.With the change of power,the hybrid system can meet the propeller power change demand and the improved DC/DC circuit can work properly.