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  • 1.
    Bachmann, Bernhard
    et al.
    Dept. Mathematics and Engineering, University of Applied Sciences, Bielefeld, Germany.
    Ochel, Lennart
    Dept. Mathematics and Engineering, University of Applied Sciences, Bielefeld, Germany.
    Ruge, Vitalij
    Dept. Mathematics and Engineering, University of Applied Sciences, Bielefeld, Germany.
    Gebremedhin, Mahder
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar.
    Fritzson, Peter
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar.
    Nezhadali, Vaheed
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska fakulteten.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska fakulteten.
    Sivertsson, Martin
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska fakulteten.
    Parallel Multiple-Shooting and Collocation Optimization with OpenModelica2012Ingår i: Proceedings of the 9th International MODELICA Conference; September 3-5; 2012; Munich; Germany, Linköping University Electronic Press, 2012, s. 659-668, artikel-id 067Konferensbidrag (Refereegranskat)
    Abstract [en]

    Nonlinear model predictive control (NMPC) has become increasingly important for today’s control engineers during the last decade. In order to apply NMPC a nonlinear optimal control problem (NOCP) must be solved which needs a high computational effort.

    State-of-the-art solution algorithms are based on multiple shooting or collocation algorithms; which are required to solve the underlying dynamic model formulation. This paper describes a general discretization scheme applied to the dynamic model description which can be further concretized to reproduce the mul-tiple shooting or collocation approach. Furthermore; this approach can be refined to represent a total collocation method in order to solve the underlying NOCP much more efficiently. Further speedup of optimization has been achieved by parallelizing the calculation of model specific parts (e.g. constraints; Jacobians; etc.) and is presented in the coming sections.

    The corresponding discretized optimization problem has been solved by the interior optimizer Ipopt. The proposed parallelized algorithms have been tested on different applications. As industrial relevant application an optimal control of a Diesel-Electric power train has been investigated. The modeling and problem description has been done in Optimica and Modelica. The simulation has been performed using OpenModelica. Speedup curves for parallel execution are presented.

  • 2.
    Nezhadali, Vaheed
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Sivertsson, Martin
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Turbocharger Dynamics Influence on Optimal Control of Diesel Engine Powered Systems2014Ingår i: SAE International Journal of Engines, ISSN 1946-3936, Vol. 7, nr 1, s. 6-13Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The importance of including turbocharger dynamics in diesel engine models are studied, especially when optimization techniques are to be used to derive the optimal controls. This is done for two applications of diesel engines where in the first application, a diesel engine in wheel loader powertrain interacts with other subsystems to perform a loading operation and engine speed is dictated by the wheel speed, while in the second application, the engine operates in a diesel-electric powertrain as a separate system and the engine speed remains a free variable. In both applications, mean value engine models of different complexities are used while the rest of system components are modeled with the aim of control study. Optimal control problems are formulated, solved, and results are analyzed for various engine loading scenarios in the two applications with and without turbocharger dynamics. It is shown that depending on the engine loading transients, fuel consumption and operation time can widely vary when the turbocharger dynamics are considered in the diesel engine model. Including these, have minor effects on fuel consumption and operation time at minimum fuel operations of the first application (~0.1 %) while the changes are considerable in the second application (up to 60%). In case of minimum time operations however, fuel consumption and operation time are highly affected in both applications implying that not considering turbocharger dynamics in the diesel engine models may lead to overestimation of the engine performance especially when the results are going to be used for control purposes.

  • 3.
    Sciarretta, A.
    et al.
    IFP Energies Nouvelles, France .
    Serrao, L.
    Dana Corporation, Italy.
    Dewangan, P.C.
    IFP Energies Nouvelles, France; IFP School, France .
    Tona, P.
    IFP Energies Nouvelles, France .
    Bergshoeff, E.N. D.
    TU Eindhoven, Netherlands.
    Bordons, C.
    University of Seville, Spain .
    Charmpa, L.
    IFP Sch, France Continental, France .
    Elbert, Ph.
    ETH Zurich, Switzerland.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Hofman, T.
    TU Eindhoven, Netherlands .
    Hubacher, M.
    TU Eindhoven, Netherlands .
    Isenegger, R.
    TU Eindhoven, Netherlands .
    Lacandia, F.
    Ohio State University, USA.
    Laveau, A.
    IFP School, France.
    Li, H.
    IFP School, France.
    Marcos, D.
    University of Seville, Spain .
    Nueesch, T.
    ETH Zurich, Switzerland.
    Onori, S.
    Ohio State University, USA .
    Pisu, P.
    Clemson University, USA .
    Rios, J.
    Clemson University, USA .
    Silvas, E.
    TU Eindhoven, Netherlands .
    Sivertsson, Martin
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Tribioli, L.
    Ohio State University, USA .
    van der Hoeven, A.-J.
    TU Eindhoven, Netherlands .
    Wu, M.
    IFP School, France.
    A control benchmark on the energy management of a plug-in hybrid electric vehicle2014Ingår i: Control Engineering Practice, ISSN 0967-0661, E-ISSN 1873-6939, Vol. 29, s. 287-298Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A benchmark control problem was developed for a special session of the IFAC Workshop on Engine and Powertrain Control, Simulation and Modeling (E-COSM 12), held in Rueil-Malmaison, France, in October 2012. The online energy management of a plug-in hybrid-electric vehicle was to be developed by the benchmark participants. The simulator, provided by the benchmark organizers, implements a model of the GM Voltec powertrain. Each solution was evaluated according to several metrics, comprising of energy and fuel economy on two driving profiles unknown to the participants, acceleration and braking performance, computational performance. The nine solutions received are analyzed in terms of the control technique adopted (heuristic rule-based energy management vs. equivalent consumption minimization strategies, ECMS), battery discharge strategy (charge depleting-charge sustaining vs. blended mode), ECMS implementation (vector-based vs. map-based), ways to improve the implementation and improve the computational performance. The solution having achieved the best combined score is compared with a global optimal solution calculated offline using the Pontryagins minimum principle-derived optimization tool HOT.

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  • 4.
    Sivertsson, Martin
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Adaptive Control Using Map-Based ECMS for a PHEV2012Ingår i: E-COSM'12 -- IFAC Workshop on Engine and Powertrain Control, Simulation and Modeling, 2012, s. 357-362Konferensbidrag (Refereegranskat)
    Abstract [en]

    A plug-in hybrid electric vehicle(PHEV) is a promising way of achieving the benefits of the electric vehicle without being limited by the electric range. This paper develops an adaptive control strategy based on a map-based ECMS approach. The control is developed andimplemented in a simulator provided by IFP Energies nouvelles for the PHEV benchmark. The implemented control strives to be as blended as possible, whilst still ensuring that all electric energy is used in the driving mission. The controller is adaptive to reduce the importance ofcorrect initial values but since the initial values aect the consumption a method is developed to estimate the optimal initial value for the controller based on driving cycle information. This is seen to work well for most driving cycles with promising consumption results. The controller also fulfills all requirements set by the PHEV Benchmark.

    Ladda ner fulltext (pdf)
    fulltext
  • 5. Beställ onlineKöp publikationen >>
    Sivertsson, Martin
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Optimal Control of Electrified Powertrains2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Elektrifiering av drivlinan i fordon är ett sätt att möta kraven på transporter med hög effektivitet och låga utsläpp. Att byta ut förbränningsmotorn mot en elmotor kan ge vinningar avseende effektivitet, prestanda och utsläpp, men till en kostnad av lägre mobilitet på grund av eletriska energilagers relativt låga energitäthet i jämförelse med fossila bränslen. Att istället komplettera förbränningsmotorn med en elmotor erbjuder möjligheten att kombinera de två systemens fördelar och samtidigt undvika nackdelarna.

    Att använda mer än en motor i drivlinan ökar komplexiteten eftersom fler frihetsgrader har introducerats. Detta ställer ökade krav på utformningen av reglersystemet för att få ut det mesta av potentialen i drivlinan. I optimal styrning använder man matematiska modeller och optimeringsalgoritmer för att beräkna hur man bäst styr det modellerade systemet. Storleken på det elektriska energilagret påverkar dock valet av optimal styrnings-metod samt vilken detaljnivå på modellerna som behövs. I avhandlingen används optimal styrning i en serie studier av hur man bäst utnyttjar de extra frihetsgraderna som elektrifieringen har introducerat.

    I en diesel-elektrisk drivlina finns det ingen mekanisk koppling mellan motorn och hjulen, likt en växellåda i ett vanligt fordon, vilket gör att dieselmotorns varvtal är en frihetsgrad som måste styras. Avsaknaden av elektriskt energilager leder också till att all elektrisk energi till elmotorn måste produceras av förbränningsmotorn exakt då den behövs. Dessa två egenskaper, i kombination med den långsamma dynamiken hos turboaggregatet, ställer detta höga krav på god transientreglering. För att studera optimal styrning krävs bra modeller med goda extrapoleringsegenskaper. Med avseende på detta utvecklas två fysik-baserade modeller som uppfyller dessa krav och dessutom är tillräckligt glatta i det relevanta arbetsområdet för att möjliggöra gradient-baserade optimeringstekniker. Med optimal styrning och en av de utvecklade modellerna visas turbons dynamik ha stor påverkan på hur drivlinan bör styras. Att försumma turbodynamiken kan leda till felaktiga uppskattningar, både av drivlinans responstid, men även hur den bör styras. Kriteriet, det vill säga om bränsle eller tidsåtgången minimeras, påverkar också vilken motorvarvtal-motormoment-väg som är optimal, även om det visas att den tidsoptimala lösningen är nästan bränsleoptimal. För att ytterligare öka frihetsgraden i drivlinan kan ett elektriskt energilager användas för att assistera i transienterna. Detta visar sig vara särskilt användbart för att minska responstiden hos drivlinan, men hur det ska använda beror på tidshorisonten på optimeringsproblemet

    De resulterande optimala styrsignalerna är i vissa fall oscillerande där konstanta styrsignaler förväntas. Detta visas vara vare sig en effekt av den använda diskretiseringen eller modelleringsvalen som är gjorda. Istället är det för de lösta problemen faktiskt optimalt att använda periodiska styrsignaler för vissa stationära arbetspunkter. I experiment visas att pumparbetet skiljer sig beroende på om periodiska eller konstanta styrsignaler används, även om medelvärdet är detsamma. Huruvida detta ökar effektiviteten eller inte beror på arbetspunkt och periodtid.

    För hybridelektriska fordon (HEV) så minskar batteriets storlek effekten av dålig transientreglering då batteriet kan användas för att kompensera för den långsamma förbränningsmotordynamiken. Istället blir problemet i huvudsak hur mycket och när batteriet ska användas för att få god bränsleekonomi. En adaptiv mapp-baserad ekvivalentförbruknings-minimerande styrlag (ECMS) med återkopplad reglering baserad på batteriets laddningsnivå, utvecklas och testas i riktigt fordon med gott resultat, även vid dålig initialisering av regulatorn.

    För plug-in hybrider (PHEV) är batteriet större och kan dessutom laddas från elnätet, vilket medför möjlighet till rent elektrisk drift och att det är önskvärt att använda energin i batteriet under köruppdraget. För att minska energiåtgången är det däremot ofta lönsamt att blanda energin från bränsle och batteriet kontinuerligt under köruppdraget och se till att batteriet töms lagom till slutet av köruppdraget. För att åstadkomma detta måste då även urladdningstakten bestämmas. En regulator utvecklas för att minimera energiåtgången för en PHEV, det vill säga som försöker använda lagom av batteriet så det ska räcka hela vägen, men inte längre. Denna regulator implementeras för ett referensproblem, med gott resultat även för okända körcykler, trots ett minimum av framtidskunskap.

    Delarbeten
    1. Optimal Transient Control Trajectories in Diesel-Electric Systems-Part I: Modeling, Problem Formulation, and Engine Properties
    Öppna denna publikation i ny flik eller fönster >>Optimal Transient Control Trajectories in Diesel-Electric Systems-Part I: Modeling, Problem Formulation, and Engine Properties
    2015 (Engelska)Ingår i: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 137, nr 2, artikel-id 021601Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A nonlinear four state-three input mean value engine model (MVEM), incorporating the important turbocharger dynamics, is used to study optimal control of a diesel-electric powertrain during transients. The optimization is conducted for the two criteria, minimum time and fuel, where both engine speed and engine power are considered free variables in the optimization. First, steps from idle to a target power are studied and for steps to higher powers the controls for both criteria follow a similar structure, dictated by the maximum torque line and the smoke-limiter. The end operating point, and how it is approached is, however, different. Then, the power transients are extended to driving missions, defined as, that a certain power has to be met as well as a certain energy has to be produced. This is done both with fixed output profiles and with the output power being a free variable. The time optimal control follows the fixed output profile even when the output power is free. These solutions are found to be almost fuel optimal despite being substantially faster than the minimum fuel solution with variable output power. The discussed control strategies are also seen to hold for sequences of power and energy steps.

    Ort, förlag, år, upplaga, sidor
    American Society of Mechanical Engineers (ASME), 2015
    Nationell ämneskategori
    Elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-114415 (URN)10.1115/1.4028359 (DOI)000348050800006 ()
    Tillgänglig från: 2015-03-02 Skapad: 2015-02-20 Senast uppdaterad: 2018-01-30
    2. Optimal Transient Control Trajectories in Diesel-Electric Systems-Part II: Generator and Energy Storage Effects
    Öppna denna publikation i ny flik eller fönster >>Optimal Transient Control Trajectories in Diesel-Electric Systems-Part II: Generator and Energy Storage Effects
    2015 (Engelska)Ingår i: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 137, nr 2, artikel-id 021602Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The effects of generator model and energy storage on the optimal control of a diesel-electric powertrain in transient operation are studied. Two different types of problems are solved, minimum fuel and minimum time, with different generator models and limits as well as with an extra energy storage. For this aim, a four-state mean value engine model (MVEM) is used together with models for the generator and energy storage losses. In the optimization both the engines output power and speed are free variables. The considered transients are steps from idle to target power with different amounts of freedom, defined as requirements on produced energy, before the requested power has to be met. The main characteristics are seen to be independent of generator model and limits; they, however, shift the peak efficiency regions and therefore the stationary points. For minimum fuel transients, the energy storage remains virtually unused for all requested energies, for minimum time it is used to reduce the response time. The generator limits are found to have the biggest impact on the fuel economy, whereas an energy storage could significantly reduce the response time. The possibility to reduce the response time is seen to hold for a large range of values of energy storage parameters. The minimum fuel solutions remain unaffected when changing the energy storage parameters, implying it is not beneficial to use an energy storage if fuel consumption is to be minimized. Close to the minimum time solution, the fuel consumption with low required energy is quite sensitive to variations in duration, for larger energies it is not. Near the minimum fuel solution changes in duration have only minor effects on the fuel consumption.

    Ort, förlag, år, upplaga, sidor
    American Society of Mechanical Engineers (ASME), 2015
    Nationell ämneskategori
    Elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-114416 (URN)10.1115/1.4028360 (DOI)000348050800007 ()
    Tillgänglig från: 2015-03-02 Skapad: 2015-02-20 Senast uppdaterad: 2018-01-30
    3. Turbocharger Dynamics Influence on Optimal Control of Diesel Engine Powered Systems
    Öppna denna publikation i ny flik eller fönster >>Turbocharger Dynamics Influence on Optimal Control of Diesel Engine Powered Systems
    2014 (Engelska)Ingår i: SAE International Journal of Engines, ISSN 1946-3936, Vol. 7, nr 1, s. 6-13Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The importance of including turbocharger dynamics in diesel engine models are studied, especially when optimization techniques are to be used to derive the optimal controls. This is done for two applications of diesel engines where in the first application, a diesel engine in wheel loader powertrain interacts with other subsystems to perform a loading operation and engine speed is dictated by the wheel speed, while in the second application, the engine operates in a diesel-electric powertrain as a separate system and the engine speed remains a free variable. In both applications, mean value engine models of different complexities are used while the rest of system components are modeled with the aim of control study. Optimal control problems are formulated, solved, and results are analyzed for various engine loading scenarios in the two applications with and without turbocharger dynamics. It is shown that depending on the engine loading transients, fuel consumption and operation time can widely vary when the turbocharger dynamics are considered in the diesel engine model. Including these, have minor effects on fuel consumption and operation time at minimum fuel operations of the first application (~0.1 %) while the changes are considerable in the second application (up to 60%). In case of minimum time operations however, fuel consumption and operation time are highly affected in both applications implying that not considering turbocharger dynamics in the diesel engine models may lead to overestimation of the engine performance especially when the results are going to be used for control purposes.

    Ort, förlag, år, upplaga, sidor
    SAE International, 2014
    Nationell ämneskategori
    Reglerteknik
    Identifikatorer
    urn:nbn:se:liu:diva-117316 (URN)10.4271/2014-01-0290 (DOI)
    Tillgänglig från: 2015-04-23 Skapad: 2015-04-23 Senast uppdaterad: 2018-01-30
    4. Optimal and real-time control potential of a diesel-electric powertrain
    Öppna denna publikation i ny flik eller fönster >>Optimal and real-time control potential of a diesel-electric powertrain
    2014 (Engelska)Ingår i: Proceedings of the 19th World CongressThe International Federation of Automatic ControlCape Town, South Africa. August 24-29, 2014 / [ed] Edward Boje and Xiaohua Xia, Cape Town: International Federation of Automatic Control , 2014, Vol. 19, s. 4825-4830Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Real-time control strategies and their performance related to the optimal control trajectories for a diesel-electric powertrain in transient operation are studied. The considered transients are steps from idle to target power. A non-linear four state-three input mean value engine model, incorporating the important turbocharger dynamics, is used for this study. The strategies are implemented using the SAE J1939-standard for engine control and evaluated compared to both the optimal solution and the solution when the engine is restricted to follow its stationary optimal line. It is shown that with the control parameters tuned for a specific criteria both engine control strategies in the SAE J1939-standard, speed control and load control, can achieve almost optimal results, where engine load controlled shows a better trade-off between fuel economy and duration. The controllers are then extended and it is shown that it is possible to control the powertrain in a close to optimal way using the SAE J1939-standard, both with the engine speed and load controlled. However the mode where the engine is load controlled is seen to be more robust.

    Ort, förlag, år, upplaga, sidor
    Cape Town: International Federation of Automatic Control, 2014
    Serie
    World Congress, ISSN 1474-6670 ; Volume 19, Part 1
    Nyckelord
    Nonlinear and optimal automotive control; Control architectures in automotive control; Engine modelling and control
    Nationell ämneskategori
    Reglerteknik
    Identifikatorer
    urn:nbn:se:liu:diva-117333 (URN)10.3182/20140824-6-ZA-1003.01969 (DOI)978-3-902823-62-5 (ISBN)
    Konferens
    The 19th World Congress The International Federation of Automatic Control Cape Town, South Africa. August 24-29, 2014
    Tillgänglig från: 2015-04-23 Skapad: 2015-04-23 Senast uppdaterad: 2018-01-30Bibliografiskt granskad
    5. Modeling for Optimal Control: A Validated Diesel-Electric Powertrain Model
    Öppna denna publikation i ny flik eller fönster >>Modeling for Optimal Control: A Validated Diesel-Electric Powertrain Model
    2014 (Engelska)Ingår i: Proceedings of the 55th Conference on Simulation and Modelling (SIMS 55), Modelling, Simulation and Optimization, 21-22 October 2014, Aalborg, Denmark / [ed] Alireza Rezania Kolai, Kim Sørensen & Mads Pagh Nielsen, Linköping: Linköping University Electronic Press, 2014, s. 49-58Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    An optimal control ready model of a diesel-electric powertrain is developed,validated and provided to the research community. The aim ofthe model is to facilitate studies of the transient control of diesel-electricpowertrains and also to provide a model for developers of optimizationtools. The resulting model is a four state three control mean valueengine model that captures the significant nonlinearity of the diesel engine, while still being continuously differentiable.

    Ort, förlag, år, upplaga, sidor
    Linköping: Linköping University Electronic Press, 2014
    Serie
    Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 108
    Nationell ämneskategori
    Reglerteknik
    Identifikatorer
    urn:nbn:se:liu:diva-117334 (URN)978-91-7519-376-2 (ISBN)
    Konferens
    SIMS 2014 - 55th International Conference on Simulation and Modelling
    Tillgänglig från: 2015-04-23 Skapad: 2015-04-23 Senast uppdaterad: 2018-02-15Bibliografiskt granskad
    6. An Optimal Control Benchmark: Transient Optimization of a Diesel-Electric Powertrain
    Öppna denna publikation i ny flik eller fönster >>An Optimal Control Benchmark: Transient Optimization of a Diesel-Electric Powertrain
    2014 (Engelska)Ingår i: Proceedings of the 55th International Conference on Simulation and Modelling (SIMS 55), 21-22 October, Modelling, Simulation and Optimization / [ed] Alireza Rezania Kolai, Kim Sørensen & Mads Pagh Nielsen, Linköping University Electronic Press, 2014, s. 59-63Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    An optimal control benchmark is presented and discussed. The benchmark is optimal transient control of a nonlinear four state three control model of a diesel-electric powertrain and constructed in such a manner that it is available in several versions to be of interest for developers of optimal control tools at different levels of development. This includes with and without time as a parameter as well as with and without time varying constraints.

    Ort, förlag, år, upplaga, sidor
    Linköping University Electronic Press, 2014
    Serie
    Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 108
    Nationell ämneskategori
    Reglerteknik
    Identifikatorer
    urn:nbn:se:liu:diva-117335 (URN)978-91-7519-376-2 (ISBN)
    Konferens
    SIMS 2014 - 55th International Conference on Simulation and Modelling, October 21-22, Aalborg, Denmark
    Tillgänglig från: 2015-04-23 Skapad: 2015-04-23 Senast uppdaterad: 2018-02-20Bibliografiskt granskad
    7. Model and discretization impact on oscillatory optimal control for a diesel-electric powertrain
    Öppna denna publikation i ny flik eller fönster >>Model and discretization impact on oscillatory optimal control for a diesel-electric powertrain
    2015 (Engelska)Ingår i: 4th IFAC Workshop on Engine and Powertrain Control, Simulation and Modeling E-COSM 2015 Columbus, Ohio, USA, 23-26 August 2015, Elsevier, 2015, Vol. 48(15), s. 66-71Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    A mean value engine model is used to study optimal control of a diesel-electric powertrain. The resulting optimal controls are shown to be highly oscillating for certain operating points, raising the question whether this is an artifact of discretization, modeling choices or a phenomenon available in real engines. Several model extensions are investigated and their corresponding optimal control trajectories are studied. It is shown that the oscillating controls cannot be explained by the implemented extensions to the previously published model, nor by the discretization, showing that for certain operating points the optimal solution is periodic.

    Ort, förlag, år, upplaga, sidor
    Elsevier, 2015
    Serie
    IFAC-PapersOnLine, ISSN 2405-8963
    Nationell ämneskategori
    Reglerteknik
    Identifikatorer
    urn:nbn:se:liu:diva-117336 (URN)10.1016/j.ifacol.2015.10.010 (DOI)
    Konferens
    4th IFAC Workshop on Engine and Powertrain Control, Simulation and Modeling E-COSM 2015 Columbus, Ohio, USA, 23-26 August 2015
    Anmärkning

    At the time for thesis presentation publication was in status: Manuscript

    Tillgänglig från: 2015-04-23 Skapad: 2015-04-23 Senast uppdaterad: 2018-01-30Bibliografiskt granskad
    8. Optimal stationary control of diesel engines using periodic control
    Öppna denna publikation i ny flik eller fönster >>Optimal stationary control of diesel engines using periodic control
    2017 (Engelska)Ingår i: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering, ISSN 0954-4070, E-ISSN 2041-2991, Vol. 231, nr 4, s. 457-475Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Measurements and optimal control are used to study whether the fuel economy of a diesel engine can be improved through periodic control of the wastegate, illustrating how modern optimal control tools can be used to identify non-trivial solutions that can improve performance. The measurements show that the pumping torque of the engine is changed when the wastegate is controlled in a periodic manner versus stationary even if the mean position is the same. If this decreases the fuel consumption or not is seen to be frequency and operating point dependent. The measurements indicate that the phenomenon occurs in the time scales capturable by mean value engine models (MVEM). The operating points are further analyzed using a MVEM and optimal control. It is shown that whether the optimal solution exhibits periodic oscillations or not is operating point dependent, but is not due to the instantaneous nature of the controls. Even if an actuator model is added the oscillations persist for reasonable time constants, the frequency of the oscillations is however affected. Further it is shown that the periodic control can be predicted by optimal periodic control theory and that the frequency of the control affects the resulting efficiency.

    Ort, förlag, år, upplaga, sidor
    Sage Publications, 2017
    Nyckelord
    Optimal periodic control, diesel engines, optimal control, internal combustion engines, wastegate control
    Nationell ämneskategori
    Reglerteknik
    Identifikatorer
    urn:nbn:se:liu:diva-117337 (URN)10.1177/0954407016640631 (DOI)000397211700002 ()2-s2.0-85014504643 (Scopus ID)
    Anmärkning

    At the time for thesis presentation publication was in status: Manuscript

    Tillgänglig från: 2015-04-23 Skapad: 2015-04-23 Senast uppdaterad: 2018-01-30Bibliografiskt granskad
    9. Adaptive Control of a Hybrid Powertrain with Map-based ECMS
    Öppna denna publikation i ny flik eller fönster >>Adaptive Control of a Hybrid Powertrain with Map-based ECMS
    2011 (Engelska)Ingår i: Proceedings of the 18th IFAC World Congress, 2011 / [ed] Sergio Bittanti, Angelo Cenedese, Sandro Zampieri, 2011, s. 2949-2954Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    To fully utilize the fuel reduction potential of a hybrid powertrain requires a careful design of the energy management control algorithms. Here a controller is created using mapbased equivalent consumption minimization strategy and implemented to function without any knowledge of the future driving mission. The optimal torque distribution is calculated oine and stored in tables. Despite only considering stationary operating conditions and average battery parameters, the result is close to that of deterministic dynamic programming. Eects of making the discretization of the tables sparser are also studied and found to have only minor eects on the fuel consumption. The controller optimizes the torque distribution for the current gear as well as assists the driver by recommending the gear that would give the lowest consumption. Two ways of adapting the control according to the battery state of charge are proposed and investigated. One of the adaptive strategies is experimentally evaluated and found to ensure charge sustenance despite poor initial values.

    Serie
    World Congress, ISSN 1474-6670 ; Volume 18, Part 1
    Nyckelord
    Hybrid Vehicles, Adaptive Control, Automotive Control, Optimal Control
    Nationell ämneskategori
    Reglerteknik
    Identifikatorer
    urn:nbn:se:liu:diva-84957 (URN)10.3182/20110828-6-IT-1002.02091 (DOI)978-390266193-7 (ISBN)
    Konferens
    18th IFAC World Congress; August 28-September 2, Milano; Italy
    Tillgänglig från: 2012-10-29 Skapad: 2012-10-29 Senast uppdaterad: 2018-01-30Bibliografiskt granskad
    10. A control benchmark on the energy management of a plug-in hybrid electric vehicle
    Öppna denna publikation i ny flik eller fönster >>A control benchmark on the energy management of a plug-in hybrid electric vehicle
    Visa övriga...
    2014 (Engelska)Ingår i: Control Engineering Practice, ISSN 0967-0661, E-ISSN 1873-6939, Vol. 29, s. 287-298Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A benchmark control problem was developed for a special session of the IFAC Workshop on Engine and Powertrain Control, Simulation and Modeling (E-COSM 12), held in Rueil-Malmaison, France, in October 2012. The online energy management of a plug-in hybrid-electric vehicle was to be developed by the benchmark participants. The simulator, provided by the benchmark organizers, implements a model of the GM Voltec powertrain. Each solution was evaluated according to several metrics, comprising of energy and fuel economy on two driving profiles unknown to the participants, acceleration and braking performance, computational performance. The nine solutions received are analyzed in terms of the control technique adopted (heuristic rule-based energy management vs. equivalent consumption minimization strategies, ECMS), battery discharge strategy (charge depleting-charge sustaining vs. blended mode), ECMS implementation (vector-based vs. map-based), ways to improve the implementation and improve the computational performance. The solution having achieved the best combined score is compared with a global optimal solution calculated offline using the Pontryagins minimum principle-derived optimization tool HOT.

    Ort, förlag, år, upplaga, sidor
    Pergamon Press, 2014
    Nyckelord
    Supervisory control; Plug-in hybrid electric vehicles; Energy management; Optimal control; Rule-based control
    Nationell ämneskategori
    Elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-109361 (URN)10.1016/j.conengprac.2013.11.020 (DOI)000339133700026 ()
    Tillgänglig från: 2014-08-15 Skapad: 2014-08-15 Senast uppdaterad: 2018-01-30Bibliografiskt granskad
    11. Design and Evaluation of Energy Management using Map-Based ECMS for the PHEV Benchmark
    Öppna denna publikation i ny flik eller fönster >>Design and Evaluation of Energy Management using Map-Based ECMS for the PHEV Benchmark
    2015 (Engelska)Ingår i: Oil & gas science and technology, ISSN 1294-4475, E-ISSN 1953-8189, Vol. 70, nr 1, s. 195-211Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Plug-in Hybrid Electric Vehicles (PHEV) provide a promising way of achieving the benefits of the electric vehicle without being limited by the electric range, but they increase the importance of the supervisory control to fully utilize the potential of the powertrain. The winning contribution in the PHEV Benchmark organized by IFP Energies nouvelles is described and evaluated. The control is an adaptive strategy based on a map-based Equivalent Consumption Minimization Strategy (ECMS) approach, developed and implemented in the simulator provided for the PHEV Benchmark. The implemented control strives to be as blended as possible, whilst still ensuring that all electric energy is used in the driving mission. The controller is adaptive to reduce the importance of correct initial values, but since the initial values affect the consumption, a method is developed to estimate the optimal initial value for the controller based on driving cycle information. This works well for most driving cycles with promising consumption results. The controller performs well in the benchmark; however, the driving cycles used show potential for improvement. A robustness built into the controller affects the consumption more than necessary, and in the case of altitude variations the control does not make use of all the energy available. The control is therefore extended to also make use of topography information that could be provided by a GPS which shows a potential further decrease in fuel consumption.

    Ort, förlag, år, upplaga, sidor
    Institut Francais du Petrole, 2015
    Nationell ämneskategori
    Elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-117268 (URN)10.2516/ogst/2014018 (DOI)000351444400013 ()
    Tillgänglig från: 2015-04-22 Skapad: 2015-04-21 Senast uppdaterad: 2019-01-04
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  • 6.
    Sivertsson, Martin
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    An Optimal Control Benchmark: Transient Optimization of a Diesel-Electric Powertrain2014Ingår i: Proceedings of the 55th International Conference on Simulation and Modelling (SIMS 55), 21-22 October, Modelling, Simulation and Optimization / [ed] Alireza Rezania Kolai, Kim Sørensen & Mads Pagh Nielsen, Linköping University Electronic Press, 2014, s. 59-63Konferensbidrag (Refereegranskat)
    Abstract [en]

    An optimal control benchmark is presented and discussed. The benchmark is optimal transient control of a nonlinear four state three control model of a diesel-electric powertrain and constructed in such a manner that it is available in several versions to be of interest for developers of optimal control tools at different levels of development. This includes with and without time as a parameter as well as with and without time varying constraints.

    Ladda ner fulltext (pdf)
    fulltext
  • 7.
    Sivertsson, Martin
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Design and Evaluation of Energy Management using Map-Based ECMS for the PHEV Benchmark2015Ingår i: Oil & gas science and technology, ISSN 1294-4475, E-ISSN 1953-8189, Vol. 70, nr 1, s. 195-211Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Plug-in Hybrid Electric Vehicles (PHEV) provide a promising way of achieving the benefits of the electric vehicle without being limited by the electric range, but they increase the importance of the supervisory control to fully utilize the potential of the powertrain. The winning contribution in the PHEV Benchmark organized by IFP Energies nouvelles is described and evaluated. The control is an adaptive strategy based on a map-based Equivalent Consumption Minimization Strategy (ECMS) approach, developed and implemented in the simulator provided for the PHEV Benchmark. The implemented control strives to be as blended as possible, whilst still ensuring that all electric energy is used in the driving mission. The controller is adaptive to reduce the importance of correct initial values, but since the initial values affect the consumption, a method is developed to estimate the optimal initial value for the controller based on driving cycle information. This works well for most driving cycles with promising consumption results. The controller performs well in the benchmark; however, the driving cycles used show potential for improvement. A robustness built into the controller affects the consumption more than necessary, and in the case of altitude variations the control does not make use of all the energy available. The control is therefore extended to also make use of topography information that could be provided by a GPS which shows a potential further decrease in fuel consumption.

  • 8.
    Sivertsson, Martin
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Generator Effects on the Optimal Control of a Power Assisted Diesel-Electric Powertrain2013Ingår i: IEEE VPPC 2013 – The 9th IEEE Vehicle Power and Propulsion Conference, Institute of Electrical and Electronics Engineers (IEEE), 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Optimal control of a diesel-electric powertrain in transient operation is studied. The attention is on how generator limits affect the solution, as well as how the addition of a small energy storage can assist in the transients. Two different types of problems are solved, minimum fuel and minimum time, with different generator limits as well as with and without an extra energy storage. In the optimization both the output power and engine speed are free variables. For this aim a 4-state mean value engine model is used together with models for the generator and energy storage losses. The considered transients are steps from idle to target power with different amounts of freedom, defined as requirements on produced energy, before the requested power has to be met. For minimum fuel transients the energy storage remains virtually unused for all requested energies, for minimum time it does not. The generator limits are found to have the biggest impact on the fuel economy, whereas an energy storage could significantly reduce the response time.

  • 9.
    Sivertsson, Martin
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Model and discretization impact on oscillatory optimal control for a diesel-electric powertrain2015Ingår i: 4th IFAC Workshop on Engine and Powertrain Control, Simulation and Modeling E-COSM 2015 Columbus, Ohio, USA, 23-26 August 2015, Elsevier, 2015, Vol. 48(15), s. 66-71Konferensbidrag (Refereegranskat)
    Abstract [en]

    A mean value engine model is used to study optimal control of a diesel-electric powertrain. The resulting optimal controls are shown to be highly oscillating for certain operating points, raising the question whether this is an artifact of discretization, modeling choices or a phenomenon available in real engines. Several model extensions are investigated and their corresponding optimal control trajectories are studied. It is shown that the oscillating controls cannot be explained by the implemented extensions to the previously published model, nor by the discretization, showing that for certain operating points the optimal solution is periodic.

  • 10.
    Sivertsson, Martin
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Modeling for Optimal Control: A Validated Diesel-Electric Powertrain Model2014Ingår i: Proceedings of the 55th Conference on Simulation and Modelling (SIMS 55), Modelling, Simulation and Optimization, 21-22 October 2014, Aalborg, Denmark / [ed] Alireza Rezania Kolai, Kim Sørensen & Mads Pagh Nielsen, Linköping: Linköping University Electronic Press, 2014, s. 49-58Konferensbidrag (Refereegranskat)
    Abstract [en]

    An optimal control ready model of a diesel-electric powertrain is developed,validated and provided to the research community. The aim ofthe model is to facilitate studies of the transient control of diesel-electricpowertrains and also to provide a model for developers of optimizationtools. The resulting model is a four state three control mean valueengine model that captures the significant nonlinearity of the diesel engine, while still being continuously differentiable.

    Ladda ner fulltext (pdf)
    fulltext
  • 11.
    Sivertsson, Martin
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Optimal and real-time control potential of a diesel-electric powertrain2014Ingår i: Proceedings of the 19th World CongressThe International Federation of Automatic ControlCape Town, South Africa. August 24-29, 2014 / [ed] Edward Boje and Xiaohua Xia, Cape Town: International Federation of Automatic Control , 2014, Vol. 19, s. 4825-4830Konferensbidrag (Refereegranskat)
    Abstract [en]

    Real-time control strategies and their performance related to the optimal control trajectories for a diesel-electric powertrain in transient operation are studied. The considered transients are steps from idle to target power. A non-linear four state-three input mean value engine model, incorporating the important turbocharger dynamics, is used for this study. The strategies are implemented using the SAE J1939-standard for engine control and evaluated compared to both the optimal solution and the solution when the engine is restricted to follow its stationary optimal line. It is shown that with the control parameters tuned for a specific criteria both engine control strategies in the SAE J1939-standard, speed control and load control, can achieve almost optimal results, where engine load controlled shows a better trade-off between fuel economy and duration. The controllers are then extended and it is shown that it is possible to control the powertrain in a close to optimal way using the SAE J1939-standard, both with the engine speed and load controlled. However the mode where the engine is load controlled is seen to be more robust.

    Ladda ner fulltext (pdf)
    fulltext
  • 12.
    Sivertsson, Martin
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Optimal Short Driving Mission Control for a Diesel-Electric Powertrain2012Ingår i: IEEE VPPC 2012 -- The 8th IEEE Vehicle Power and Propulsion Conference, IEEE , 2012, s. 413-418Konferensbidrag (Refereegranskat)
    Abstract [en]

    Time and fuel optimal control for a diesel-electric powertrain in transient operation is studied using a four state, three controls non-linear mean value engine model. In the studied transients the engine starts at idle and stops when the generated energy fulfills the driving mission requirement. During the driving mission both the engine speed and output power are allowed to vary, but with a constraint on power. Two strategiesare then developed and evaluated. One where the driving mission is optimized with the generator power considered a free variable,and a second strategy where the accelerating phase of the transient is first optimized and then the optimal controls fora fixed generator power are used. The time optimal control is shown to be almost as fuel efficient as the fuel optimal controleven though the gain in time is large. The time optimal control also has the advantage of using constant power output, making itsimple and easily implementable, whilst the fuel optimal control is more complex and changes with the length of the driving mission.

    Ladda ner fulltext (pdf)
    fulltext
  • 13.
    Sivertsson, Martin
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Optimal stationary control of diesel engines using periodic control2017Ingår i: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering, ISSN 0954-4070, E-ISSN 2041-2991, Vol. 231, nr 4, s. 457-475Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Measurements and optimal control are used to study whether the fuel economy of a diesel engine can be improved through periodic control of the wastegate, illustrating how modern optimal control tools can be used to identify non-trivial solutions that can improve performance. The measurements show that the pumping torque of the engine is changed when the wastegate is controlled in a periodic manner versus stationary even if the mean position is the same. If this decreases the fuel consumption or not is seen to be frequency and operating point dependent. The measurements indicate that the phenomenon occurs in the time scales capturable by mean value engine models (MVEM). The operating points are further analyzed using a MVEM and optimal control. It is shown that whether the optimal solution exhibits periodic oscillations or not is operating point dependent, but is not due to the instantaneous nature of the controls. Even if an actuator model is added the oscillations persist for reasonable time constants, the frequency of the oscillations is however affected. Further it is shown that the periodic control can be predicted by optimal periodic control theory and that the frequency of the control affects the resulting efficiency.

  • 14.
    Sivertsson, Martin
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Optimal Step Responses in Diesel-Electric Systems2012Ingår i: Mechatronics'12 -- The 13th Mechatronics Forum International Conference, 2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    A non-linear four state-three input mean value engine model, incorporating the important turbocharger dynamics,is used to study optimal control of a diesel-electric powertrain during transients. The optimization is conducted for two differentcriteria, both time and fuel optimal control, and both engine speed and output power are considered free variables in theoptimization. The transients considered are steps from idle to a target power and the results of the optimization show thatthe solutions can be divided into two categories, depending on requested power. The resulting control strategies are also seento be valid for other initial conditions than idle. For steps to high power the controls for both criteria follow a similarstructure, a structure given by the maximum torque line and the smoke-limiter. The main difference between fuel and timeoptimal control is the end operating point, and how this is approached. The fuel optimal control builds more kinetic energyin the turbocharger, reducing the necessary amount of kinetic energy in the system to produce the requested power. It is foundthat the fact that it does not approach the fuel optimal operating point relates to the amount of produced energy required to getthere. For steps to low output powers the optimal controls deal with the turbocharger dynamics in a fundamentally differentway.

    Ladda ner fulltext (pdf)
    fulltext
  • 15.
    Sivertsson, Martin
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Optimal transient control and effects of a small energy storage for a diesel-electric powertrain2013Ingår i: 7th IFAC Symposium on Advances in Automotive Control, 2013 / [ed] Taketoshi Kawabe, International Federation of Automatic Control , 2013, s. 818-823Konferensbidrag (Refereegranskat)
    Abstract [en]

    Optimal control of a diesel-electric powertrain in transient operation is studied. The attention is on how generator limits affect the solution, as well as how the addition of a small energy storage can assist in the transients. Two different types of problems are solved, minimum fuel and minimum time, with different generator limits as well as with and without an extra energy storage. In the optimization both the output power and engine speed are free variables. For this aim a 4-state mean value engine model is used together with models for the generator and energy storage losses. The considered transients are steps from idle to target power with different amounts of freedom, defined as requirements on produced energy, before the requested power has to be met. For minimum fuel transients the energy storage remains virtually unused for all requested energies, for minimum time it does not. The generator limits are found to have the biggest impact on the fuel economy, whereas an energy storage could significantly reduce the response time.

  • 16.
    Sivertsson, Martin
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Optimal Transient Control Trajectories in Diesel-Electric Systems-Part I: Modeling, Problem Formulation, and Engine Properties2015Ingår i: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 137, nr 2, artikel-id 021601Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A nonlinear four state-three input mean value engine model (MVEM), incorporating the important turbocharger dynamics, is used to study optimal control of a diesel-electric powertrain during transients. The optimization is conducted for the two criteria, minimum time and fuel, where both engine speed and engine power are considered free variables in the optimization. First, steps from idle to a target power are studied and for steps to higher powers the controls for both criteria follow a similar structure, dictated by the maximum torque line and the smoke-limiter. The end operating point, and how it is approached is, however, different. Then, the power transients are extended to driving missions, defined as, that a certain power has to be met as well as a certain energy has to be produced. This is done both with fixed output profiles and with the output power being a free variable. The time optimal control follows the fixed output profile even when the output power is free. These solutions are found to be almost fuel optimal despite being substantially faster than the minimum fuel solution with variable output power. The discussed control strategies are also seen to hold for sequences of power and energy steps.

  • 17.
    Sivertsson, Martin
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Optimal Transient Control Trajectories in Diesel-Electric Systems-Part II: Generator and Energy Storage Effects2015Ingår i: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 137, nr 2, artikel-id 021602Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effects of generator model and energy storage on the optimal control of a diesel-electric powertrain in transient operation are studied. Two different types of problems are solved, minimum fuel and minimum time, with different generator models and limits as well as with an extra energy storage. For this aim, a four-state mean value engine model (MVEM) is used together with models for the generator and energy storage losses. In the optimization both the engines output power and speed are free variables. The considered transients are steps from idle to target power with different amounts of freedom, defined as requirements on produced energy, before the requested power has to be met. The main characteristics are seen to be independent of generator model and limits; they, however, shift the peak efficiency regions and therefore the stationary points. For minimum fuel transients, the energy storage remains virtually unused for all requested energies, for minimum time it is used to reduce the response time. The generator limits are found to have the biggest impact on the fuel economy, whereas an energy storage could significantly reduce the response time. The possibility to reduce the response time is seen to hold for a large range of values of energy storage parameters. The minimum fuel solutions remain unaffected when changing the energy storage parameters, implying it is not beneficial to use an energy storage if fuel consumption is to be minimized. Close to the minimum time solution, the fuel consumption with low required energy is quite sensitive to variations in duration, for larger energies it is not. Near the minimum fuel solution changes in duration have only minor effects on the fuel consumption.

  • 18.
    Sivertsson, Martin
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Time and Fuel Optimal Power Response of a Diesel-Electric Powertrain2012Ingår i: E-COSM'12 -- IFAC Workshop on Engine and Powertrain Control, Simulation and Modeling, 2012, s. 262-269Konferensbidrag (Refereegranskat)
    Abstract [en]

    Optimal control policies for a diesel-electric powertrain in transient operation are studied. In order to fully utilize the extra degree of freedom available in a diesel-electric powertrain, compared to a conventional powertrain, the engine-speed is allowed to vary freely.The considered transients are steps from idle to target power. A non-linear four state-three input mean value engine model, incorporating the important turbocharger dynamics, is used for this study. The study is conducted for two dierent criteria, fuel optimal control and time optimalcontrol. The results from the optimization show that the optimal controls for each criteria can be divided into two categories, one for high requested powers and one for low requested powers. For high power transients the controls for both criteria follow a similar structure, a structure givenby the maximum torque line and the smoke-limiter. The main dierence between the criteria is the end point and how it is approached. The fuel optimal control builds more kinetic energy in the turbocharger, reducing the necessary amount of kinetic energy in the system to producethe requested power. For low power transients the optimal controls deal with the turbocharger dynamics in a fundamentally dierent way.

    Ladda ner fulltext (pdf)
    fulltext
  • 19.
    Sivertsson, Martin
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Sundström, Christofer
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Adaptive Control of a Hybrid Powertrain with Map-based ECMS2011Ingår i: Proceedings of the 18th IFAC World Congress, 2011 / [ed] Sergio Bittanti, Angelo Cenedese, Sandro Zampieri, 2011, s. 2949-2954Konferensbidrag (Refereegranskat)
    Abstract [en]

    To fully utilize the fuel reduction potential of a hybrid powertrain requires a careful design of the energy management control algorithms. Here a controller is created using mapbased equivalent consumption minimization strategy and implemented to function without any knowledge of the future driving mission. The optimal torque distribution is calculated oine and stored in tables. Despite only considering stationary operating conditions and average battery parameters, the result is close to that of deterministic dynamic programming. Eects of making the discretization of the tables sparser are also studied and found to have only minor eects on the fuel consumption. The controller optimizes the torque distribution for the current gear as well as assists the driver by recommending the gear that would give the lowest consumption. Two ways of adapting the control according to the battery state of charge are proposed and investigated. One of the adaptive strategies is experimentally evaluated and found to ensure charge sustenance despite poor initial values.

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