Sizing and Dynamic modeling of a Power System for the MUN Explorer Autonomous Underwater Vehicle using a Fuel Cell and Batteries

TL;DR

This paper explores integrating a fuel cell with batteries in an AUV to enhance power capacity, reduce recharge time, and improve operational efficiency, supported by system sizing and dynamic modeling.

Contribution

It presents a novel integrated power system design for an AUV combining fuel cells and batteries, with system sizing via HOMER and dynamic analysis in MATLAB/Simulink.

Findings

Fuel cell integration increases power capacity to 68 kWh.

System sizing suggests 1kW fuel cell and 8 batteries are optimal.

Dynamic model demonstrates system behavior and voltage regulation.

Abstract

The combination of a fuel cell and batteries has promising potential for powering autonomous vehicles. The MUN Explorer Autonomous Underwater Vehicle (AUV) is built to do mapping-type missions of seabeds as well as survey missions. These missions require a great deal of power to reach underwater depths (i.e. 3000 meters). The MUN Explorer uses 11 rechargeable Lithium-ion (Li-ion) batteries as the main power source with a total capacity of 14.6kWh to 17.952kWh, and the vehicle can run for 10 hours. The draw-backs of operating the existing power system of the MUN Explorer, which was done by the researcher at the Holyrood management facility, include mobilization costs, logistics and transport, and facility access, all of which should be taken into consideration. Recharging the batteries for at least 8 hours is also very challenging and time consuming. To overcome these challenges and run the MUN Explorer for a long time, it is essential to integrate a fuel cell into an existing power system (i.e. battery bank). The integration of the fuel cell not only will increase the system power, but it will also reduce the number of batteries needed as suggested by HOMER software. In this paper, an integrated fuel cell is designed to be added into the MUN Explorer AUV along with a battery bank system to increase its power system. The system sizing is performed using HOMER software. The results from HOMER software show that a 1kW fuel cell and 8 Li-ion batteries can increase the power system capacity to 68 kWh. The dynamic model is then built in MATLAB/Simulink environment to provide a better understanding of the system behavior.The 1kW fuel cell is connected to a DC/DC Boost Converter to increase the output voltage from 24V to 48V as required by the battery and DC motor.