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Balachandran, A., Jonsson, T. U. & Eriksson, L. (2023). DC Charging Capabilities of Battery-Integrated Modular Multilevel Converters Based on Maximum Tractive Power. Electricity, 4(1), 62-77
Open this publication in new window or tab >>DC Charging Capabilities of Battery-Integrated Modular Multilevel Converters Based on Maximum Tractive Power
2023 (English)In: Electricity, E-ISSN 2673-4826, Vol. 4, no 1, p. 62-77Article in journal (Refereed) Published
Abstract [en]

The increase in the average global temperature is a consequence of high greenhouse gas emissions. Therefore, using alternative energy carriers that can replace fossil fuels, especially for automotive applications, is of high importance. Introducing more electronics into an automotive battery pack provides more precise control and increases the available energy from the pack. Battery-integrated modular multilevel converters (BI-MMCs) have high efficiency, improved controllability, and better fault isolation capability. However, integrating the battery and inverter influences the maximum DC charging power. Therefore, the DC charging capabilities of 5 3-phase BI-MMCs for a 40-ton commercial vehicle designed for a maximum tractive power of 400 kW was investigated. Two continuous DC charging scenarios are considered for two cases: the first considers the total number of submodules during traction, and the second increases the total number of submodules to ensure a maximum DC charging voltage of 1250 V. The investigation shows that both DC charging scenarios have similar maximum power between 1 and 3 MW. Altering the number of submodules increases the maximum DC charging power at the cost of increased losses.

Place, publisher, year, edition, pages
MDPI, 2023
National Category
Energy Systems
Identifiers
urn:nbn:se:liu:diva-191802 (URN)10.3390/electricity4010005 (DOI)
Available from: 2023-02-15 Created: 2023-02-15 Last updated: 2023-03-16Bibliographically approved
Reindl, A., Eriksson, L., Niemetz, M., Sangyoung, P. & Meier, H. (2022). Control Concepts for a Decentralized Battery Management System to Optimize Reliability and Battery Operation. In: Proceedings of the 16th International Renewable Energy Storage Conference (IRES2022): . Paper presented at Proceedings of the 16th International Renewable Energy Storage Conference (IRES2022), 20 - 22 September 2022, Düsseldorf, Germany 2022.
Open this publication in new window or tab >>Control Concepts for a Decentralized Battery Management System to Optimize Reliability and Battery Operation
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2022 (English)In: Proceedings of the 16th International Renewable Energy Storage Conference (IRES2022), 2022Conference paper, Published paper (Other academic)
Abstract [en]

Battery systems are used in a wide range of safety-relevant applications, such as electric vehicles, unmanned aerial vehiclesand home storage systems. Safety, reliability and availability of the battery system therefore play a key role. In addition, theuseful service lifetime of the batteries determines the environmental impact and economic efficiency of the overall system. Onepossible solution is to give batteries a second life in applications with lower requirements in terms of dynamic behavior or capacity.Heterogeneous battery systems consist of batteries with differences in cell technology, age, capacity, and optimal operating range.To meet the safety, reliability, and availability requirements a scalable, Decentralized Battery Management System (DBMS) basedon a distributed control system is proposed. Batteries, generators, and loads have Local Control Units (LCUs) consisting of amicrocontroller, a measurement unit, and a DC/DC converter with adjustable voltage and current limits. These LCUs are the basis forthe communication-based, cooperative system control and enhance the reliability and scalability of the battery system compared toconventional centralized structures. They record and manage the operating parameters and provide the basis for predictive energymanagement and battery residual value estimation. As a fallback strategy, a droop-based control of the DC/DC converters is used inaddition to the communication-based one. Transition conditions between the control modes are defined and the control methods arecompared and differentiated. The performance and the resulting benefits of batteries are determined by the control strategies. In thispaper, the requirements for the control strategies for different operating modes, including startup, severe fluctuations of the DC powerline voltage, and safe shutdown, are analyzed.

Keywords
Renewable energy sources, battery management system, second life battery, decentralized control, distributed control, control strategies, droop control, battery optimal operation
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-192984 (URN)
Conference
Proceedings of the 16th International Renewable Energy Storage Conference (IRES2022), 20 - 22 September 2022, Düsseldorf, Germany 2022
Available from: 2023-04-06 Created: 2023-04-06 Last updated: 2023-04-12
Holmbom, R. & Eriksson, L. (2022). Development of a Control-Oriented Cylinder Air-Charge Model for Gasoline Engines with Dual Independent Cam Phasing. In: : . Paper presented at WCX SAE World Congress Experience, 2022.
Open this publication in new window or tab >>Development of a Control-Oriented Cylinder Air-Charge Model for Gasoline Engines with Dual Independent Cam Phasing
2022 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Cylinder air-charge is one of the most important parts of the torque control in a gasoline engine, due to the necessity to keep a stoichiometric air-fuel ratio, for the three-way catalyst to work efficiently. Throttle and phasing of the camshafts are actuators that have a big effect on the cylinder air-charge, this results in a cross-coupling between the actuators. One approach to handle the cross-coupling that occurs with multiple actuators is to use model predictive control (MPC), that handles the cross-coupling through the use of models and optimization. Models that support computation of gradients and hessians are desirable for use in MPC.To support the model design experimental data of cylinder pressure, from an inline four-cylinder engine with dual independent cam phasing, supported by gas exchange simulation, the effects from variable valve timing on the cylinder air-charge are investigated during the valve overlap period. The analysis highlights the effect of a phase described using the path of the least resistance as having an inhibiting effect on the backflow of residual gases during the overlap period. Making the flow reversal over the exhaust valves an important event to keep track of the residual gases.From the analysis of the effects on air-charge, a model is developed and proposed for the volumetric efficiency, the engine’s ability to fill the cylinders with fresh air. The model structure is derived using partial volumes, and it fits into the Mean Value Engine Model (MVEM) framework, making it is especially useful for control design. The model is validated against stationary measurements and the results show that the proposed model captures the important behaviors and changes in the air-charge related to the variable valve timing. Making it suitable for usage in an MPC framework.

National Category
Control Engineering Vehicle Engineering
Identifiers
urn:nbn:se:liu:diva-192270 (URN)10.4271/2022-01-0414 (DOI)
Conference
WCX SAE World Congress Experience, 2022
Available from: 2023-03-09 Created: 2023-03-09 Last updated: 2023-03-09
Xu, F., Tsunogawa, H., Kako, J., Hu, X., Li, S. E., Shen, T., . . . Guardiola, C. (2022). Real-time energy optimization of HEVs under-connected environment: a benchmark problem and receding horizon-based solution. CONTROL THEORY AND TECHNOLOGY, 20, 145-160
Open this publication in new window or tab >>Real-time energy optimization of HEVs under-connected environment: a benchmark problem and receding horizon-based solution
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2022 (English)In: CONTROL THEORY AND TECHNOLOGY, ISSN 2095-6983, Vol. 20, p. 145-160Article in journal (Refereed) Published
Abstract [en]

In this paper, we propose a benchmark problem for the challengers aiming to energy efficiency control of hybrid electric vehicles (HEVs) on a road with slope. Moreover, it is assumed that the targeted HEVs are in the connected environment with the obtainment of real-time information of vehicle-to-everything (V2X), including geographic information, vehicle-to-infrastructure (V2I) information and vehicle-to-vehicle (V2V) information. The provided simulator consists of an industrial-level HEV model and a traffic scenario database obtained through a commercial traffic simulator, where the running route is generated based on real-world data with slope and intersection position. The benchmark problem to be solved is the HEVs powertrain control using traffic information to fulfill fuel economy improvement while satisfying the constraints of driving safety and travel time. To show the HEV powertrain characteristics, a case study is given with the speed planning and energy management strategy.

Place, publisher, year, edition, pages
SPRINGERNATURE, 2022
Keywords
Powertrain control; Connected and automated vehicles; Hybrid electric vehicles; Vehicle-to-everything
National Category
Transport Systems and Logistics
Identifiers
urn:nbn:se:liu:diva-184262 (URN)10.1007/s11768-022-00086-y (DOI)000773874100001 ()
Available from: 2022-04-11 Created: 2022-04-11 Last updated: 2023-05-29Bibliographically approved
Leek, V. & Eriksson, L. (2021). Accurate Simulation for Numerical Optimal Control. In: Esko Juuso, Bernt Lie, Erik Dahlquist, and Jari Ruuska (Ed.), The First SIMS EUROSIM Conference on Simulation and Modelling SIMS EUROSIM 2021: The 62nd SIMS Conference on Simulation and Modelling SIMS 2021. Paper presented at SIMS EUROSIM 2021 (pp. 148-155). Linköping University Electronic Press
Open this publication in new window or tab >>Accurate Simulation for Numerical Optimal Control
2021 (English)In: The First SIMS EUROSIM Conference on Simulation and Modelling SIMS EUROSIM 2021: The 62nd SIMS Conference on Simulation and Modelling SIMS 2021 / [ed] Esko Juuso, Bernt Lie, Erik Dahlquist, and Jari Ruuska, Linköping University Electronic Press, 2021, p. 148-155Conference paper, Published paper (Refereed)
Abstract [en]

Accurate simulation of the numerical optimal control in software environments where call to simulation routines is explicit, for instance Matlab and SciPy. A discussion on the simulation aspects of numerical optimal control, how it may fail, and how such erroneous results can be detected using accurate simulation. The key contribution is how to accurately include a piecewise constant control input in the simulations, which is discussed in detail, including code examples. The technique is demonstrated on an example problem which show how simulation can be used to analyze optimal control problems with uncertainty, but also demonstrates how erroneous simulation may lead to erroneous conclusions.

Place, publisher, year, edition, pages
Linköping University Electronic Press, 2021
Series
Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 185
Keywords
simulation, optimal control, direct multiple shooting, direct collocation
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-189844 (URN)10.3384/ecp21185148 (DOI)978-91-7929-219-5 (ISBN)
Conference
SIMS EUROSIM 2021
Available from: 2022-11-09 Created: 2022-11-09 Last updated: 2022-11-09
Leek, V. & Eriksson, L. (2021). Developing a Dynamic Diesel Engine Model for Energy Optimal Control. In: Esko Juuso, Bernt Lie, Erik Dahlquist, and Jari Ruuska (Ed.), The First SIMS EUROSIM Conference on Simulation and Modelling SIMS EUROSIM 2021: The 62nd SIMS Conference on Simulation and Modelling SIMS 2021. Paper presented at SIMS EUROSIM 2021 (pp. 123-131). Linköping University Electronic Press
Open this publication in new window or tab >>Developing a Dynamic Diesel Engine Model for Energy Optimal Control
2021 (English)In: The First SIMS EUROSIM Conference on Simulation and Modelling SIMS EUROSIM 2021: The 62nd SIMS Conference on Simulation and Modelling SIMS 2021 / [ed] Esko Juuso, Bernt Lie, Erik Dahlquist, and Jari Ruuska, Linköping University Electronic Press, 2021, p. 123-131Conference paper, Published paper (Refereed)
Abstract [en]

A dynamic heavy-duty Euro 6 diesel engine model for energy optimal control is developed. The modeling focus ison accuracy in the entire engine operating range, with attention to the region of highest efficiency and physically plausible extrapolation. The effect of the air-to-fuel ratio on combustion efficiency is studied, and it is demonstrated how this influences the energy optimal transient control. A convenient, physics-based, method for pressure sensor bias estimation is also presented.

Place, publisher, year, edition, pages
Linköping University Electronic Press, 2021
Series
Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 185
Keywords
Diesel engine modeling, Optimal control
National Category
Energy Engineering
Identifiers
urn:nbn:se:liu:diva-189842 (URN)10.3384/ecp21185123 (DOI)978-91-7929-219-5 (ISBN)
Conference
SIMS EUROSIM 2021
Available from: 2022-11-09 Created: 2022-11-09 Last updated: 2022-11-09
Ekberg, K. & Eriksson, L. (2020). A Comparison of Optimal Gear Shifts for Stiff and Flexible Driveshafts During Accelerations. In: : . Paper presented at 21st IFAC World Congress 2020, Berlin 12 July 2020 through 17 July 2020 (pp. 14413-14419). Elsevier, 53(2)
Open this publication in new window or tab >>A Comparison of Optimal Gear Shifts for Stiff and Flexible Driveshafts During Accelerations
2020 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Reducing the fuel consumption is important and much development work is on engine optimization for best stationary fuel consumption. Here, a solution is developed for the transient operation to get fuel optimal accelerations, considering the actuation of fuel injection, wastegate control and gear utilization. The transient acceleration scenario studied is; a truck is approaching a red light at slow rolling speed, the light turns green and the truck shall be accelerated to 50 km/h with minimum fuel. Optimal control is used to find the fuel optimal control strategies. By using a dynamic engine model, taking the turbocharger dynamics into consideration, the engine air fuel ratio is taken into account. The differences and similarities between a stiff and flexible driveline model, are analyzed. The results show that the most dominating effect is the turbocharger dynamics of the engine. The two drivelines have similar gear changing strategies while the finer details differ due to the additional degrees of freedom that are present in the flexible driveline.

Place, publisher, year, edition, pages
Elsevier, 2020
Series
IFAC-PapersOnLine, ISSN 2405-8963
Keywords
Optimal control, gear changes, dynamic model, driveline
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-175497 (URN)10.1016/j.ifacol.2020.12.1410 (DOI)000652593600197 ()2-s2.0-85105028438 (Scopus ID)
Conference
21st IFAC World Congress 2020, Berlin 12 July 2020 through 17 July 2020
Note

Funding: Swedens Innovation Agency [2016-05152]; LINK-SIC Linkoping Center for Sensor Informatics and Control; Scania CV AB

Available from: 2021-05-05 Created: 2021-05-05 Last updated: 2022-01-19Bibliographically approved
Holmer, O., Willems, F., Blomgren, F. & Eriksson, L. (2020). Optimal Aftertreatment Pre-Heat Strategy for Minimum Tailpipe NOx Around Green Zones. In: WCX SAE World Congress Experience: . Paper presented at 2020 WCX SAE World Congress Experience. SAE International
Open this publication in new window or tab >>Optimal Aftertreatment Pre-Heat Strategy for Minimum Tailpipe NOx Around Green Zones
2020 (English)In: WCX SAE World Congress Experience, SAE International , 2020Conference paper, Published paper (Refereed)
Abstract [en]

Green zones are challenging problems for the thermal management systems of hybrid vehicles. This is because within the green zone the engine is turned off, and the only way to keep the aftertreatment system warm is lost. This means that there is a risk of leaving the green zone with a cold and ineffective aftertreatment system, resulting in high emissions.A thermal management strategy that heats the aftertreatment system prior to turning off the engine, in an optimal way, to reduce the NOx emissions when the engine is restarted, is developed. The strategy is also used to evaluate under what conditions pre-heating is a suitable strategy, by evaluating the performance in simulations using a model of a heavy-duty diesel powertrain and scenario designed for this purpose.The results show that, for the studied vehicle, pre-heating of the aftertreatment system is an effective strategy to reduce NOx for engine-off events shorter than two hours, and is most effective for engine off events of around 1.5 hours. The results also show that for engine-off events longer than two hours, pre-heating quickly becomes an inefficient strategy. At this point, ammonia storage when the engine is turned off is more important, and pre-heating can even make the results worse, since an increased SCR temperature results in lower ammonia storage before turning off the engine, which is detrimental for NOx conversion during the restart.

Place, publisher, year, edition, pages
SAE International, 2020
National Category
Vehicle Engineering Control Engineering
Identifiers
urn:nbn:se:liu:diva-169734 (URN)10.4271/2020-01-0361 (DOI)
Conference
2020 WCX SAE World Congress Experience
Available from: 2020-09-17 Created: 2020-09-17 Last updated: 2022-01-13
Eriksson, L. (2020). Robustness analysis of dual actuator EGR controllers in marine two-stroke diesel engines. Journal of Marine Engineering & Technology, 19(sup1), 17-30
Open this publication in new window or tab >>Robustness analysis of dual actuator EGR controllers in marine two-stroke diesel engines
2020 (English)In: Journal of Marine Engineering & Technology, ISSN 2046-4177, E-ISSN 2056-8487, Vol. 19, no sup1, p. 17-30Article in journal (Refereed) Published
Abstract [en]

Exhaust Gas Recirculation (EGR) was recently introduced in large marine two-stroke diesel engines to reduce NOx-emissions. Controlling EGR flow during accelerations, while keeping good acceleration performance is challenging, due to delays in the scavenge receiver oxygen measurement and upper limits on fuel for avoiding black smoke. Previous oxygen feedback controllers struggled during accelerations, but a new EGR-controller based on adaptive feedforward (AFF) has been successful. Nevertheless, further analysis and tests are required before deploying the controller to more EGR ships. A simulation platform is a great asset to test controllers before expensive real-world experiments are conducted. A new EGR flow controller is proposed and tested in a complete ship simulation model. Several acceleration scenarios show that the low load area is most challenging. Controller robustness is analysed in this area, showing that pressure sensor bias in the EGR flow estimator is the most critical factor, which could lead to black smoke formation. This can be prevented with sensor calibration or by using a differential pressure sensor. Errors in the parameters of the flow estimators are not as important. This is a useful result because the right parameters of the flow estimators might be difficult to obtain, on a new engine.

Place, publisher, year, edition, pages
Taylor & Francis, 2020
National Category
Vehicle Engineering Control Engineering Marine Engineering
Identifiers
urn:nbn:se:liu:diva-169743 (URN)10.1080/20464177.2020.1712065 (DOI)
Available from: 2020-09-17 Created: 2020-09-17 Last updated: 2020-10-12
Eriksson, L. (2019). An overview of various control benchmarks with a focus on automotive control. Control Theory and Technology, 17(2), 121-130
Open this publication in new window or tab >>An overview of various control benchmarks with a focus on automotive control
2019 (English)In: Control Theory and Technology, ISSN 2095-6983, Vol. 17, no 2, p. 121-130Article in journal (Refereed) Published
Abstract [en]

There exists a gap between control theory and control practice, i.e., all control methods suggested by researchers are not implemented in real systems and, on the other hand, many important industrial problems are not studied in the academic research. Benchmark problems can help close this gap and provide many opportunities for members in both the controls theory and application communities. The goal is to survey and give pointers to different general controls and modeling related benchmark problems that can serve as inspiration for future benchmarks and then specifically focus the benchmark coverage on automotive control engineering application. In the paper reflections are given on how different categories of benchmark designers, benchmark solvers and third part users can benefit from providing, solving, and studying benchmark problems. The paper also collects information about several benchmark problems and gives pointers to papers than give more detailed information about different problems that have been presented.

Place, publisher, year, edition, pages
South China University of Technology, Academy of Mathematics and Systems Science, CAS and Springer-Verlag GmbH Germany, 2019
Keywords
Benchmark, automotive control, robust control, robotics, engine control, powertrain control, system identification
National Category
Control Engineering Computer Sciences Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-156602 (URN)10.1007/s11768-019-8268-5 (DOI)000702362800002 ()
Available from: 2019-04-26 Created: 2019-04-26 Last updated: 2023-09-08
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-8646-8998

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