Nonlinear model predictive control for thermal management in plug-in hybrid electric vehicles

© 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.A nonlinear model predictive control (NMPC) for the thermal management (TM) of Plug-in Hybrid Electric Vehicles (PHEVs) is presented. TM in PHEVs is crucial to ensure good components performance and durability in all possible climate scenarios. A drawback of accurate TM solutions is the higher electrical consumption due to the increasing number of low voltage (LV) actuators used in the cooling circuits. Hence, more complex control strategies are needed for minimizing components thermal stress and at the same time electrical consumption. In this context, NMPC arises as a powerful method for achieving multiple objectives in Multiple input- Multiple output systems. This paper proposes an NMPC for the TM of the High Voltage (HV) battery and the power electronics (PE) cooling circuit in a PHEV. It distinguishes itself from the previously NMPC reported methods in the automotive sector by the complexity of its controlled plant which is highly nonlinear and controlled by numerous variables. The implemented model of the plant, which is based on experimental data and multi- domain physical equations, has been validated using six different driving cycles logged in a real vehicle, obtaining a maximum error, in comparison with the real temperatures, of 2C. For one of the six cycles, an NMPC software-in-the loop (SIL) is presented, where the models inside the controller and for the controlled plant are the same. This simulation is compared to the finite-state machine-based strategy performed in the real vehicle. The results show that NMPC keeps the battery at healthier temperatures and in addition reduces the cooling electrical consumption by more than 5%. In terms of the objective function, an accumulated and weighted sum of the two goals, this improvement amounts 30%. Finally, the online SIL presented in this paper, suggests that the used optimizer is fast enough for a future implementation in the vehicle.Accepted versio

Quantitative description of ion transport via plasma membrane of yeast and small cells

Modeling of ion transport via plasma membrane needs identification and quantitative understanding of the involved processes. Brief characterization of main ion transport systems of a yeast cell (Pma1, Ena1, TOK1, Nha1, Trk1, Trk2, non-selective cation conductance) and determining the exact number of molecules of each transporter per a typical cell allow us to predict the corresponding ion flows. In this review a comparison of ion transport in small yeast cell and several animal cell types is provided. The importance of cell volume to surface ratio is emphasized. The role of cell wall and lipid rafts is discussed in respect to required increase in spatial and temporal resolution of measurements. Conclusions are formulated to describe specific features of ion transport in a yeast cell. Potential directions of future research are outlined based on the assumptions.Comment: 22 pages, 6 figures, 1 tabl

Ultrafast nonlinear optical response of Dirac fermions in graphene

The speed of solid-state electronic devices, determined by the temporal dynamics of charge carriers, could potentially reach unprecedented petahertz frequencies through direct manipulation by optical fields, consisting in a million-fold increase from state-of-the-art technology. In graphene, charge carrier manipulation is facilitated by exceptionally strong coupling to optical fields, from which stems an important back-action of photoexcited carriers. Here we investigate the instantaneous response of graphene to ultrafast optical fields, elucidating the role of hot carriers on sub-100 fs timescales. The measured nonlinear response and its dependence on interaction time and field polarization reveal the back-action of hot carriers over timescales commensurate with the optical field. An intuitive picture is given for the carrier trajectories in response to the optical-field polarization state. We note that the peculiar interplay between optical fields and charge carriers in graphene may also apply to surface states in topological insulators with similar Dirac cone dispersion relations.Peer ReviewedPostprint (published version

Pay-at-the-Pump Auto Insurance

PAY-AT-THE-PUMP is a proposal to replace the current insurance system of lump sum payments for automobile insurance by a mechanism whereby motorists pay for their insurance as they buy fuel for their vehicles. PAY-AT-THE-PUMP has several advantages. It reduces insurance cost and cross subsidies and enhances equity. It also benefits the environment, safety, balance of payments, and security. In this paper we study limited but very important issues in the theory and implementation of PAY-AT-THE-PUMP insurance. We address issues of efficiency, subsidy, equity, externalities, safety, insurance cost and cost of insuring the uninsured motorist under a PAY-AT-THE-PUMP regime. We use the insurance industry’s criticisms of mandatory auto insurance as a lens through which we view PAY-AT-THE-PUMP insurance and ask how PAY-AT-THE-PUMP fares by comparison. Finally we address one aspect of insurance that has been neglected in the current debate -- the human dimension of the problem of uninsured motorist and the contribution PAY-AT-THE-PUMP can make to solve this problem.

An Energy-Efficient, Dynamic Voltage Scaling Neural Stimulator for a Proprioceptive Prosthesis

Accepted versio

Synchronization modulation increases transepithelial potentials in MDCK monolayers through Na/K pumps

Peer reviewedPublisher PD

The Intersection of Urban Form and Mileage Fees: Findings from the Oregon Road User Fee Pilot Program, Research Report 10-04

This report analyzes data from the 2006-2007 Oregon Road User Fee Pilot program to assess if and how urban form variables correlate with travel behavior changes that participants made in response to the mileage-based fee program. It finds that charging a noticeably higher fee for driving in congested conditions can successfully motivate households to reduce their VMT in those times and places where congestion is most a problem. Households in both traditional (mixed use, dense, transit-accessible) and suburban (single-use, low density) neighborhoods will likely reduce their peak-hour and overall travel under a charging scheme that charges a high-rate for peak-hour travel, though households in the traditional neighborhoods will do so more. It also finds that a mileage fee program that charges a high rate during the peak hour is likely to strengthen the underlying influence of urban form on travel behavior. In other words, land use probably will matter more to transportation planning if the nation shifts to a new paradigm of mileage-based financing and pricing system. For transportation policy-makers, this raises another layer of consideration when designing the optimal rate structure to achieve policy goals—either reduced VMT and congestion or sustained funding sources. For urban planners, this offers a wonderful opportunity to move towards a sustainable built environment through revised and compatible land use regulation under the context of a mileage-based fee. The research also reveals that program design could significantly affect a household’s response to a mileage-based fee program. Particularly in Portland, the establishment of an endowment account for participants actually increased household VMT when a flat-rate fee was charged, the opposite to policy-makers’ expectation. One possible explanation is that paying the mileage-based fees once a month, instead of paying the gas tax at each visit to the pump, may have encouraged households to drive more due to the reduced gas price at the pump