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An ECMS-Based Controller for the Electrical System of a Passenger Vehicle

Couch, Jeremy Robert
http://rave.ohiolink.edu/etdc/view?acc_num=osu1366076350

Abstract Details

2013, Master of Science, Ohio State University, Mechanical Engineering.
A primary concern for automotive manufacturers is increasing the fuel economy of their vehicles. One way to accomplish this is by reducing the losses associated with operating the ancillary loads such as the loads of the vehicle’s electrical system. In the electrical system of a vehicle, the alternator provides current to the electrical loads. The difference between the load current demand and the current provided by the alternator is either accepted or supplied by the battery. Therefore, the current demand of the electrical loads can be met by the alternator, the battery or a combination thereof. While improving the efficiency of the actual components of the electrical system (alternator, battery and electrical loads) is beneficial, additional gains can be realized with a smart control strategy for the alternator. Conventional alternator control strategies make little use of the battery; the power demand from the electrical loads is almost solely met by the alternator. However, since the alternator is directly connected to the engine, this results in increased fuel consumption, particularly at idle speed conditions. To this extent, more advanced control strategies could be implemented to make use of the battery energy buffer to limit the use of the alternator at low engine efficiency conditions. The focus of this thesis is the design of an advanced alternator control strategy. First, a model of a vehicle’s electrical system is developed with control design in mind. The system is modeled starting from a lumped-parameter, energy-based characterization of the battery and alternator. This is followed by a thorough calibration using experimental data and, finally, validation on a vehicle chassis dynamometer considering a standard (production) alternator control strategy. Next, a novel alternator control algorithm is designed by applying the Equivalent Consumption Minimization Strategy (ECMS), a well known energy management approach often used to control the powertrain of hybrid electric vehicles. This strategy works by determining the optimal alternator current to minimize the instantaneous fuel consumption while complying with input and state of charge constraints. The ECMS algorithm was extensively calibrated for a variety of drive cycles and load current profiles. This proposed control strategy was then compared in simulation to the production alternator controller and fuel consumption reductions of up to 2.18% have been shown. An adaptive ECMS (A-ECMS) is then defined, using feedback from the battery’s state of charge to dynamically tune the ECMS calibration parameter in real-time. Simulation results for the A-ECMS show fuel savings compared to the baseline alternator control strategy that are on the same order of magnitude as the ECMS. Furthermore, a robustness study verifies the A-ECMS is insensitive to model inaccuracies, poor tuning of the parameters and variations in the load current profile.
Marcello Canova (Advisor)
Lisa Fiorentini (Committee Member)
Giorgio Rizzoni (Committee Member)
184 p.
Automotive Engineering; Mechanical Engineering
automotive; energy management; vehicle electrical system; control oriented model; adaptive ECMS

Recommended Citations

Citations

  • Couch, J. R. (2013). An ECMS-Based Controller for the Electrical System of a Passenger Vehicle [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366076350

    APA Style (7th edition)

  • Couch, Jeremy. An ECMS-Based Controller for the Electrical System of a Passenger Vehicle. 2013. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1366076350.

    MLA Style (8th edition)

  • Couch, Jeremy. "An ECMS-Based Controller for the Electrical System of a Passenger Vehicle." Master's thesis, Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366076350

    Chicago Manual of Style (17th edition)

osu1366076350
1,103
© 2013, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.