Control and Optimization of Fuel Cell Based Powertrain for Automotive Applications
Doktorsavhandling, 2022

Fuel cell powered electric vehicles, with fast-refueling time, high energy density, and zero CO2 emissions, are becoming a promising solution for future fossil-free transportation. However, the relatively slow dynamic response and the inability of recovering the regenerative energy make vehicles solely powered by fuel cells not an immediately attractive solution. Instead, hybrid vehicles powered by fuel cells combined with energy buffers such as batteries and supercapacitors could be of more interest. Due to the unique characteristics of each energy buffer, the vehicle performance may vary with the hybrid energy storage system configuration. This thesis performs a comprehensive study on various energy storage configurations for applications in fuel cell hybrid electric vehicles.

This thesis first examines the fuel cell/supercapacitor passive hybrid configuration where the fuel cell and supercapacitor share the same DC-link voltage. The power distribution between them is inherently determined by their internal resistances. Therefore, the DC-link voltage varies and depends on the vehicle power demand. In this work, a fuel cell/supercapacitor passive hybrid powertrain is first modeled and evaluated. Simulation results show that the energy efficiency is 53%–71% during propulsion and 84%–94% during braking, respectively. Moreover, a 3 kW lab-scale fuel cell/supercapacitor passive hybrid system is designed and investigated. Experimental results show that the fuel cell takes time to respond to a load change, while the supercapacitor provides the transient power, which makes it possible to downsize the fuel cell.

Since the passive configuration loses the active controllability, this thesis further considers a fully-active fuel cell/supercapacitor system to improve the controllability of the power distribution. This configuration requires a boost converter for the fuel cell and a buck-boost converter for the supercapacitor. In this work, an adaptive power split method is used to smooth the fuel cell current and prevent the supercapacitor from exceeding its lower and upper charge limits. The cut-off frequency of the low-pass filter is adaptively controlled by the spectrum area ratio. Experimental results show that the supercapacitor state-of-charge is effectively controlled within the desired range. Moreover, a load disturbance compensator is proposed and demonstrated to improve the control performance such that the DC-link voltage fluctuation caused by the load current variation is significantly reduced.

This thesis also investigates the cost-effectiveness of different energy buffers hybridized with fuel cells in various trucking applications. First, a chance-constraint co-design optimization problem is formulated. Convex modeling steps are presented to show that the problem can be decomposed and solved using convex programming. Results show that the power rating of the electric machine can be dramatically reduced when the delivered power is satisfied in a probabilistic sense. Moreover, the hybridization of fuel cells with lithium-ion batteries results in the lowest cost while the vehicle using lithium-ion capacitors as the energy buffer can carry the heaviest payload. This work also develops a robust co-design optimization framework considering the uncertainties in parameters (e.g., vehicle movement) and design decision variables (e.g., scaling factors of fuel cells and batteries). Results show that these uncertainties might propagate to uncertainties in state variables (e.g., battery energy) and optimization variables (e.g., battery power), leading to a larger battery capacity and therefore a higher total cost in robust optimal solutions.

In summary, this thesis performs a comprehensive study on control and optimization of fuel cell based powertrains for automotive applications. This will provide a guidance on component selection and sizing, as well as powertrain system configuration and optimization for design of fuel cell powered electric vehicles.

DC-link voltage

Fuel cell

Batteries

Robust co-design optimization

Cut-off frequency

Supercapacitors

Load disturbance compensator

Electric vehicles

Power distribution

Convex programming

Chance-constraint co-design optimization

EE, lecture hall, Hörsalsvägen 11, EDIT trappa C, D och H

Författare

Qian Xun

Chalmers, Elektroteknik, Elkraftteknik, Elmaskiner och kraftelektronik

Joint Component Sizing and Energy Management for Fuel Cell Hybrid Electric Trucks

IEEE Transactions on Vehicular Technology,; Vol. In press(2022)

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An adaptive power split strategy with a load disturbance compensator for fuel cell/supercapacitor powertrains

Journal of Energy Storage,; Vol. 44(2021)

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Design and experimental verification of a fuel cell/supercapacitor passive configuration for a light vehicle

Journal of Energy Storage,; Vol. 33(2021)

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Drive Cycle Energy Efficiency of Fuel Cell/Supercapacitor Passive Hybrid Vehicle System

IEEE Transactions on Industry Applications,; Vol. 57(2021)p. 894-903

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Evaluation of fluctuating voltage topology with fuel cells and supercapacitors for automotive applications

International Journal of Energy Research,; Vol. 43(2019)p. 4807-4819

Artikel i vetenskaplig tidskrift

Intelligent Power Allocation with Load Disturbance Compensator in Fuel Cell/Supercapacitor System for Vehicle Applications

ITEC 2019 - 2019 IEEE Transportation Electrification Conference and Expo,; (2020)p. 489-494

Paper i proceeding

Energy Efficiency Comparison of Hybrid Powertrain Systems for Fuel-Cell-Based Electric Vehicles

ITEC 2019 - 2019 IEEE Transportation Electrification Conference and Expo,; (2020)

Paper i proceeding

Modelling and simulation of fuel cell/ supercapacitor passive hybrid vehicle system

2019 IEEE Energy Conversion Congress and Exposition, ECCE 2019,; (2019)p. 2690-2696

Paper i proceeding

A Comparative Study of Fuel Cell Electric Vehicles Hybridization with Battery or Supercapacitor

SPEEDAM 2018 Proceedings: International Symposium on Power Electronics, Electrical Drives, Automation and Motion,; (2018)p. 389-394

Paper i proceeding

Internal combustion engine vehicles in general emit a large amount of greenhouse gas (GHG). One way of reducing GHG emissions from transportation is electrification of vehicles, in combination with renewable energy sources. Vehicles powered by fuel cells, with fast refueling time, high energy density, and zero CO2 emissions, are becoming a promising solution for future fossil-free transportation. However, the relatively slow dynamic response and the inability of recovering the braking energy make vehicles solely powered by fuel cells not an immediately attractive solution. Instead, hybrid vehicles powered by fuel cells combined with energy buffers such as batteries and supercapacitors could be of more interest. Because of the unique characteristics of energy buffers, the vehicle performance may vary with the hybrid energy storage system configuration.

This study investigates the control and optimization strategies of fuel cell based powertrain configurations for automotive applications, including passenger cars, buses, and trucks. In the passive hybrid configuration with fuel cells and supercapacitors, the power distribution between these two components is inherently determined by their internal resistances, leading to a varied DC-link voltage. In this thesis, the energy efficiencies of the components and the entire powertrain are analyzed and evaluated. A lab-scale experiment platform is designed, implemented, and evaluated for light vehicle applications. To improve the controllability of the power distribution between different energy storage components, an adaptive power split method with a load disturbance compensator is proposed for a fully active hybrid powertrain configuration and its performance is experimentally verified under two bus driving cycles. This study also investigates the cost effectiveness of different energy buffers hybridized with fuel cells in various trucking applications. A robust co-design optimization framework is developed considering the uncertainties in driving conditions and design decision variables.

In summary, this thesis performs a comprehensive study on control and optimization of fuel cell based powertrains for automotive applications. This will provide guidance on component selection and sizing, as well as powertrain system configuration and optimization for design of fuel cell powered electric vehicles.

Trends in Energy Storage Technologies (TEST)

Chalmers, 2020-01-01 -- 2020-06-01.

Bränslecellsdrivsystem med svävande spänning

Energimyndigheten (44935-1), 2018-01-01 -- 2018-08-31.

Cost-effective drivetrains for fuel cell powered EVs

Kompetenscentrum för forskning och utveckling av el- och hybridfordon (SHC), 2017-01-01 -- 2019-06-30.

Drivkrafter

Hållbar utveckling

Styrkeområden

Energi

Ämneskategorier

Elektroteknik och elektronik

ISBN

978-91-7905-639-1

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5105

Utgivare

Chalmers

EE, lecture hall, Hörsalsvägen 11, EDIT trappa C, D och H

Mer information

Senast uppdaterat

2022-05-22