The Variable DC Approach for Improved Powertrain Energy Efficiency in Fuel Cell-Fed Marine Vessels

Arbër Haxhiu

The Variable DC Approach for Improved Powertrain Energy Efficiency in Fuel Cell-Fed Marine Vessels

Julkaisun otsikon käännös: Vaihtuva tasavirtamenetelmä polttokennokäyttöisten merialusten voimansiirron energiatehokkuuden parantamiseksi

Arbër Haxhiu

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Meriteollisuudessa on meneillään merkittävä siirtymä hiilipohjaisista polttoaineista ympäristölle vähemmän haitallisiin polttoaineisiin. Siirtymää ohjaavat ensisijaisesti kansainväliset määräykset, jotka vaativat merkittäviä rajoituksia ympäristölle haitallisten päästöjen enimmäismäärälle. Vetyä ja polttokennoja pidetään usein yhtenä tehokkaana keinona meriteollisuuden hiilidioksidipäästöjen vähentämiseksi. Niiden käyttöönotto merialuksilla on kuitenkin vielä erittäin alkuvaiheessa ja yksiä tärkeimpiä syitä hitaalle käyttöönotolle on sekä korkeat investointi- että käyttökustannukset. Tässä opinnäytetyössä kehitetään uutta sähköistä integrointi- ja toimintakonseptia tasasähköön perustuviin polttokennokäyttöisiin laivojen voimajärjestelmiin. Konsepti on suunniteltu merkittävästi vähentämään voimansiirron kokonaisenergiahäviöitä ja siten alentamaan polttoaineen kulutusta, mikä edelleen johtaa aluksen käyttökustannusten alenemiseen. Käyttökustannusten aleneminen on erittäin edullista polttokennojen omaksumisen nopeuttamiseksi merialusten päävoimanlähteiksi, mikä puolestaan parantaisi myös merenkulun ympäristövaikutuksia. Opinnäytetyössä tutkittu konsepti on nimeltään Variable DC Approach, ja se perustuu operointiin muuttuvalla tasavirtajakelujännitteellä. Yksinkertaisuudessaan konsepti jättää pois yhden tehon muunnosvaiheen, joka on tyypillisesti olemassa polttokennojen ja yhteisen tasajännitekiskoston välillä. Tehonmuunnosvaiheen poisjättäminen eliminoi kaikki korkeataajuiseen kytkentään liittyvät energiahäviöt mainitussa tehonmuuntovaiheessa. Tässä opinnäytetyössä kehitetään ja esitellään kehittyneitä tehon ja jännitteen ohjausjärjestelmiä, joita tarvitaan Variable DC Approach -konseptin tehokkaaseen hyödyntämiseen. Variable DC Approach - konseptin toteutettavuus validoidaan käyttämällä reaaliaikaista hardware-in-loop testeausjärjestelymää, joka on suunniteltu erityisesti merialusten tehojärjestelmän testaukseen. Suoritettujen testien perusteella konsepti toimii hyvin sekä normaaleissa että vikoja sisältävissä käyttöolosuhteissa. Lisäksi testit osoittavat konseptin mahdollistavan jopa 28% paremman kokonaisvoimansiirron energiatehokkuuden verrattuna toimintaan tavanomaisella kiinteällä tasajännitteellä. Lisäksi konseptin toinen myönteinen etu on korkeataajuisen polttokennovirran aaltoilun eliminointi, mikä voi pitkällä aikavälillä johtaa polttokennojen tehokkaampaan toimintaan.

Julkaisun otsikon käännös	Vaihtuva tasavirtamenetelmä polttokennokäyttöisten merialusten voimansiirron energiatehokkuuden parantamiseksi
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Valvoja/neuvonantaja	Kyyrä, Jorma, Vastuuprofessori Kanerva, Sami, Ohjaaja, Ulkoinen henkilö
Kustantaja	Aalto University
Painoksen ISBN	978-952-64-1004-3
Sähköinen ISBN	978-952-64-1005-0
Tila	Julkaistu - 2022
OKM-julkaisutyyppi	G5 Artikkeliväitöskirja

Tutkimusalat

hybridi
hyötysuhde
häviöt
merenkulku
polttokennot
sähköjärjestelmän ohjaus
vaihtuva dc jännite
voimansiirto

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http://urn.fi/URN:ISBN:978-952-64-1005-0

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@phdthesis{7b9f062ac4784e3683211e9f1bf92268,

title = "The Variable DC Approach for Improved Powertrain Energy Efficiency in Fuel Cell-Fed Marine Vessels",

abstract = "The maritime industry is undergoing a significant transition from carbon-based fuels towards less environmentally harmful fuels. This transition is primarily being driven by international regulations calling for significant limitations on maximum-allowed environmentally harmful emissions. Hydrogen and fuel cells are often touted as one potential means for the decarbonization of the maritime industry. However, their adoption on board marine vessels is still in its infancy; some of the main reasons for the slow adoption being both high investment and operating costs. This dissertation proposes a new electric integration and operation concept for DC-based fuel cell-fed marine vessel power systems. The concept is designed to enable significant reductions in total powertrain energy losses, thereby reducing operating fuel consumption, which further leads to reduced vessel operating costs. The reduced cost of operation is highly beneficial in order to accelerate the adoption of fuel cells as main power sources for marine vessels, which in turn would also improve the environmental impact of the maritime shipping industry. The proposed concept is entitled the Variable DC Approach and is based on the variable operation of a common DC bus voltage. In its simplicity, the Variable DC Approach omits one power conversion stage which typically exists between fuel cells and a common DC bus. The omission of the power conversion stage eliminates all energy losses associated with high-frequency switching in the said power conversion stage. This dissertation develops and presents advanced power and voltage control systems necessary for efficient utilization of the Variable DC Approach concept. The feasibility of the Variable DC Approach is validated using a real-time hardware-in-loop test setup specifically designed for marine vessel power system testing. The performed validation tests show good performances during both normal and failure-containing operating conditions. Furthermore, the tests show the Variable DC Approach enables an improvement of as much as 28% in total powertrain energy efficiency compared to operating with conventional fixed DC bus voltage. In addition, another positive benefit of the Variable DC Approach is found in its elimination of the high-frequency fuel cell current ripple, which can lead to improved long-term operation of the fuel cell power sources.",

keywords = "drivetrain, efﬁciency, fuel cells, hybrid, losses, marine, power system control, variable dc voltage, hybridi, hy{\"o}tysuhde, h{\"a}vi{\"o}t, merenkulku, polttokennot, s{\"a}hk{\"o}j{\"a}rjestelm{\"a}n ohjaus, vaihtuva dc j{\"a}nnite, voimansiirto, drivetrain, efﬁciency, fuel cells, hybrid, losses, marine, power system control, variable dc voltage",

author = "Arb{\"e}r Haxhiu",

year = "2022",

language = "English",

isbn = "978-952-64-1004-3",

series = "Aalto University publication series DOCTORAL THESES",

publisher = "Aalto University",

number = "160",

address = "Finland",

school = "Aalto University",

}

TY - BOOK

T1 - The Variable DC Approach for Improved Powertrain Energy Efficiency in Fuel Cell-Fed Marine Vessels

AU - Haxhiu, Arbër

PY - 2022

Y1 - 2022

N2 - The maritime industry is undergoing a significant transition from carbon-based fuels towards less environmentally harmful fuels. This transition is primarily being driven by international regulations calling for significant limitations on maximum-allowed environmentally harmful emissions. Hydrogen and fuel cells are often touted as one potential means for the decarbonization of the maritime industry. However, their adoption on board marine vessels is still in its infancy; some of the main reasons for the slow adoption being both high investment and operating costs. This dissertation proposes a new electric integration and operation concept for DC-based fuel cell-fed marine vessel power systems. The concept is designed to enable significant reductions in total powertrain energy losses, thereby reducing operating fuel consumption, which further leads to reduced vessel operating costs. The reduced cost of operation is highly beneficial in order to accelerate the adoption of fuel cells as main power sources for marine vessels, which in turn would also improve the environmental impact of the maritime shipping industry. The proposed concept is entitled the Variable DC Approach and is based on the variable operation of a common DC bus voltage. In its simplicity, the Variable DC Approach omits one power conversion stage which typically exists between fuel cells and a common DC bus. The omission of the power conversion stage eliminates all energy losses associated with high-frequency switching in the said power conversion stage. This dissertation develops and presents advanced power and voltage control systems necessary for efficient utilization of the Variable DC Approach concept. The feasibility of the Variable DC Approach is validated using a real-time hardware-in-loop test setup specifically designed for marine vessel power system testing. The performed validation tests show good performances during both normal and failure-containing operating conditions. Furthermore, the tests show the Variable DC Approach enables an improvement of as much as 28% in total powertrain energy efficiency compared to operating with conventional fixed DC bus voltage. In addition, another positive benefit of the Variable DC Approach is found in its elimination of the high-frequency fuel cell current ripple, which can lead to improved long-term operation of the fuel cell power sources.

AB - The maritime industry is undergoing a significant transition from carbon-based fuels towards less environmentally harmful fuels. This transition is primarily being driven by international regulations calling for significant limitations on maximum-allowed environmentally harmful emissions. Hydrogen and fuel cells are often touted as one potential means for the decarbonization of the maritime industry. However, their adoption on board marine vessels is still in its infancy; some of the main reasons for the slow adoption being both high investment and operating costs. This dissertation proposes a new electric integration and operation concept for DC-based fuel cell-fed marine vessel power systems. The concept is designed to enable significant reductions in total powertrain energy losses, thereby reducing operating fuel consumption, which further leads to reduced vessel operating costs. The reduced cost of operation is highly beneficial in order to accelerate the adoption of fuel cells as main power sources for marine vessels, which in turn would also improve the environmental impact of the maritime shipping industry. The proposed concept is entitled the Variable DC Approach and is based on the variable operation of a common DC bus voltage. In its simplicity, the Variable DC Approach omits one power conversion stage which typically exists between fuel cells and a common DC bus. The omission of the power conversion stage eliminates all energy losses associated with high-frequency switching in the said power conversion stage. This dissertation develops and presents advanced power and voltage control systems necessary for efficient utilization of the Variable DC Approach concept. The feasibility of the Variable DC Approach is validated using a real-time hardware-in-loop test setup specifically designed for marine vessel power system testing. The performed validation tests show good performances during both normal and failure-containing operating conditions. Furthermore, the tests show the Variable DC Approach enables an improvement of as much as 28% in total powertrain energy efficiency compared to operating with conventional fixed DC bus voltage. In addition, another positive benefit of the Variable DC Approach is found in its elimination of the high-frequency fuel cell current ripple, which can lead to improved long-term operation of the fuel cell power sources.

KW - drivetrain

KW - efﬁciency

KW - fuel cells

KW - hybrid

KW - losses

KW - marine

KW - power system control

KW - variable dc voltage

KW - hybridi

KW - hyötysuhde

KW - häviöt

KW - merenkulku

KW - polttokennot

KW - sähköjärjestelmän ohjaus

KW - vaihtuva dc jännite

KW - voimansiirto

KW - drivetrain

KW - efﬁciency

KW - fuel cells

KW - hybrid

KW - losses

KW - marine

KW - power system control

KW - variable dc voltage

M3 - Doctoral Thesis

SN - 978-952-64-1004-3

T3 - Aalto University publication series DOCTORAL THESES

PB - Aalto University

ER -

The Variable DC Approach for Improved Powertrain Energy Efficiency in Fuel Cell-Fed Marine Vessels

Abstrakti

Tutkimusalat

YK:n kestävän kehityksen tavoitteet

Pääsy asiakirjaan

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