Modelling a fuel cell propulsion system for multicopters

Date
2019-04
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: Multirotors are used in many applications - PwC predicts that drones have a potential market value of $127.3 bn. It is expected that if beyond-visual-lineof- sight becomes legalized, current multirotor light time will be insuffcient in these applications, and investment in increasing multirotor light time will increase. The most mature technology to increase multirotor UAV light time is fuel cells. This technology has been proven to increase the light time twoto threefold, compared to LiPo-based multirotors, the current state-of-the-art technology. However, these multirotor systems are more complex to design, and no publicly-available software design tools exist. In order to solve this, a software design tool was developed. The components of a fuel cell multirotor system were modelled. Models were developed in Matlab/SimscapeTM. Experimental data was obtained using either the author's own experiments, data from manufacturers or data found in literature. The experimental data was then used to identify the unknown model constants. The component models are quite accurate, with the error mostly being small in comparison to the effect of varying a parameter. Also, % RMSE values are mostly below 3% and the R2 values are all greater than 0.97. These component models were combined to form a design tool. The usefulness of the design tool was demonstrated by running a preliminary optimization study - the light time was maximized with battery remaining state of charge as a constraint. A theoretical design was obtained with 2.39 hours light time and 38% SOC remaining.
AFRIKAANSE OPSOMMING: Multirotors word in baie toepassings gebruik - PwC voorspel dat drones 'n potensiële markwaarde van $ 127,3 miljard het. Daar word verwag dat indien die buite-visuele lyn van sig gewettig word, die huidige multirotoriese vlugtyd onvoldoende sal wees in hierdie aansoeke, en belegging in toenemende multirotoriese vlugtyd sal toeneem. Die mees volwasse tegnologie om multirotoriese UAV-vlugtyd te verhoog, is brandstofselle. Hierdie tegnologie het bewys dat die vlugtyd twee- tot drievoudig vergroot word, in vergelyking met LiPo-gebaseerde multirotors, die huidige state-of-the-art tegnologie. Hierdie multirotor-stelsels is egter meer kompleks om te ontwerp, en daar bestaan geen publieke beskikbare sagtewareontwerpgereedskap nie. Om dit op te los, is 'n sagteware-ontwerpinstrument ontwikkel. Die komponente van 'n brandstofsel multirotoriese stelsel is gemodelleer. Modelle is ontwikkel in Matlab/SimscapeTM. Eksperimentele data is verkry deur gebruik te maak van óf die outeur se eie eksperimente, data van vervaardigers of data wat in die literatuur voorkom. Die eksperimentele data is dan gebruik om die onbekende modelkonstantes te identifseer. Die komponentmodelle is redelik akkuraat, met die fout meestal klein in vergelyking met die effek om 'n parameter te verander. Ook, % RMSE waardes is meestal minder as 3% en die R2 waardes is almal groter as 0.97. Hierdie komponentmodelle is gekombineer om 'n ontwerpgereedskap te vorm. Die nut van die ontwerpgereedskap is getoon deur 'n voorlopige optimaliseringsstudie uit te voer. Die vlugtyd is gemaksimeer met die oorblywende toestand van die battery as 'n beperking. 'n Teoretiese ontwerp is verkry met 2.39 hure vlugtyd en 38% SOC oorblywend.
Description
Thesis (MEng)--Stelllenbosch University, 2019.
Keywords
Fuel tanks -- Drone aircraft, Multirotor, Drones (Aircraft), UCTD
Citation