Run-to-Run Control for Active Balancing of Lithium Iron Phosphate Battery Packs

\ua9 1986-2012 IEEE. Lithium iron phosphate battery packs are widely employed for energy storage in electrified vehicles and power grids. However, their flat voltage curves rendering the weakly observable state of charge are a critical stumbling block for charge equalization management. This paper focuses on the real-time active balancing of series-connected lithium iron phosphate batteries. In the absence of accurate in situ state information in the voltage plateau, a balancing current ratio (BCR) based algorithm is proposed for battery balancing. Then, BCR-based and voltage-based algorithms are fused, responsible for the balancing task within and beyond the voltage plateau, respectively. The balancing process is formulated as a batch-based run-to-run control problem, as the first time in the research area of battery management. The control algorithm acts in two timescales, including timewise control within each batch run and batchwise control at the end of each batch. Hardware-in-the-loop experiments demonstrate that the proposed balancing algorithm is able to release 97.1% of the theoretical capacity and can improve the capacity utilization by 5.7% from its benchmarking algorithm. Furthermore, the proposed algorithm can be coded in C language with the binary code in 118 328 bytes only and, thus, is readily implementable in real time

Load-responsive model switching estimation for state of charge of lithium-ion batteries

Accurately estimating state of charge (SoC) is very important to enable advanced management of lithium-ion batteries, however technical challenges mainly exist in the lack of a high-fidelity battery model whose parameters are sensitive to changes of the state and load condition. To address the problem, this paper explores and proposes a model switching estimation algorithm that online selects the most suitable model from its model library based on the relationship between load conditions for calibration and in practice. By leveraging a high-pass filter and the Coulomb counting, an event trigger procedure is developed to detect the estimation performance and then determine timely switching actions. This estimation algorithm is realized by adopting a gradient correction method for system identification and the unscented Kalman filter and H∞ observer for state estimation. Experimental results illustrate that the proposed algorithm is able to reproduce SoC trajectories under various operating profiles, with the root-mean-square errors bounded by 2.22%. The efficacy of this algorithm is further corroborated by comparing to single model-based estimators and two prevalent adaptive SoC estimators

Adherence to guidelines and protocols in the prehospital and emergency care setting: a systematic review

Contains fulltext : 117489.pdf (publisher's version ) (Open Access)A gap between guidelines or protocols and clinical practice often exists, which may result in patients not receiving appropriate care. Therefore, the objectives of this systematic review were (1) to give an overview of professionals' adherence to (inter)national guidelines and protocols in the emergency medical dispatch, prehospital and emergency department (ED) settings, and (2) to explore which factors influencing adherence were described in studies reporting on adherence. PubMed (including MEDLINE), CINAHL, EMBASE and the Cochrane database for systematic reviews were systematically searched. Reference lists of included studies were also searched for eligible studies. Identified articles were screened on title, abstract and year of publication (>/=1990) and were included when reporting on adherence in the eligible settings. Following the initial selection, articles were screened full text and included if they concerned adherence to a (inter)national guideline or protocol, and if the time interval between data collection and publication date was <10 years. Finally, articles were assessed on reporting quality. Each step was undertaken by two independent researchers. Thirty-five articles met the criteria, none of these addressed the emergency medical dispatch setting or protocols. Median adherence ranged from 7.8-95% in the prehospital setting, and from 0-98% in the ED setting. In the prehospital setting, recommendations on monitoring came with higher median adherence percentages than treatment recommendations. For both settings, cardiology treatment recommendations came with relatively low median adherence percentages. Eight studies identified patient and organisational factors influencing adherence. The results showed that professionals' adherence to (inter)national prehospital and emergency department guidelines shows a wide variation, while adherence in the emergency medical dispatch setting is not reported. As insight in influencing factors for adherence in the emergency care settings is minimal, future research should identify such factors to allow the development of strategies to improve adherence and thus improve quality of care

Mobility and potential bioavailability of traffic-derived trace metals in a ‘wet–dry’ tropical region, Northern Australia

The aqueous mobility and potential bioavailability of metals and metalloids in road runoff in a ‘wet–dry’ tropical location were assessed by analysing metal and\ud metalloid concentrations in particulate, total dissolved and\ud labile dissolved phases in runoff waters. Road-derived Al,\ud Cu, Pb, Sb and Zn concentrations were substantially elevated\ud in runoff when compared to receiving creek waters.\ud Median dissolved concentrations in road runoff exceeded\ud those in creek waters by up to an order of magnitude.\ud Leaching experiments of road sediments confirmed that\ud several metals and metalloids were released in high concentrations from road sediments. Labile Zn and Cu concentrations measured by diffusion gradients in thin films\ud (DGT) showed that almost all dissolved Zn and up to half\ud of dissolved Cu in runoff waters and in road sediment\ud leachate were potentially bioavailable. Comparisons of\ud dissolved metal concentrations in receiving waters affected\ud by road runoff with ecosystem guideline levels, indicated a\ud risk of reaching toxic levels of Cu and Zn in the receiving\ud waters in the absence of adequate treatment or dilution.\ud Low dilution rates of road runoff are likely to occur during\ud late ‘dry’ season/early ‘wet’ season storms which have the\ud potential to produce high metal concentrations derived\ud from long periods of accumulation of road sediment at a\ud time when creek flow rates are at their annual minimum