873 research outputs found

    Online reduced complexity parameter estimation technique for equivalent circuit model of lithium-ion battery

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    For control-oriented battery management applications in electric vehicles, Equivalent Circuit Model (ECM) of battery packs offer acceptable modelling accuracy and simple mathematical equations for including the cell parameters. However, in real-time applications, circuit parameters continuously changes by varying operating conditions and state of the battery and thus, require an online parameter estimator. The estimator must update the battery parameters with less computational complexity suitable for real-time processing. This paper presents a novel Online Reduced Complexity (ORC) technique for the online parameter estimation of the ECM. The proposed technique provides significantly less complexity (hence estimation time) compared to the existing technique, but without compromising the accuracy. We use Trust Region Optimization (TRO) based Least Square (LS) method as an updating algorithm in the proposed technique and validate our results experimentally using Nissan Leaf (pouch) cells and with the help of standard vehicular testing cycles, i.e. the Dynamic Driving Cycle (DDC), and the New European Driving Cycle (NEDC)

    A single-phase synchronization technique for grid-connected energy storage system under faulty grid conditions

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    The control of a single-phase grid-connected energy storage system (ESS) requires a very fast and accurate estimation of grid voltage frequency and phase angle. A phase-locked loop (PLL) based synchronization algorithm usually extracts this information. The operation and control of the entire system are directly affected by the performance of PLL. In this article, a novel advanced single-phase PLL (ASĎ•PLL) technique with reduced complexity is proposed for the fast and accurate extraction of grid information in an ESS under distorted and abnormal grid conditions, including harmonics, interharmonics, dc offset, and grid faults. The proposed method provides a faster dynamic response, lower frequency overshoot, and accurate estimation under off-nominal grid frequencies with reduced computational complexity in comparison with the existing method. The advanced performance of the proposed ASĎ•PLL is verified through the simulation and experimental results

    An improved pre-filtering moving average filter based synchronization algorithm for single-phase V2G application

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    The performance and overall operation of grid- connected electric vehicle is directly affected by abnormal grid conditions. In this regard, Moving Average Filter (MAF) provide high noise cancellation capability and require less computational resources. However, the conventional in-loop MAF based synchronization suffers from slower dynamic response. In this paper, an improved pre-filtering MAF based PLL (IPMAFPLL) is proposed where MAF is removed from the control-loop and placed in the pre-filtering stage to improve the dynamic response of system. The phase drift provided by MAF under off-nominal frequency is further mitigated by introducing a compensation factor in the pre-filtering stage. The proposed technique is compared with conventional MAF-PLL and non-adaptive MAF- PLL. The simulation and experimental results show that our proposed approach have lower frequency overshoot and improved performance towards compensating grid harmonics under nominal and off-nominal grid frequencies

    Simultaneous Shape and Size Optimization of Double-layer Grids with Nonlinear Behavior

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    The main aim of this paper is to present a new solution for simultaneous shape and size optimization of double-layer grids. In order to find the optimum design, Enhanced Colliding Bodies Optimization method is applied to the optimum design of the most common examples of double-layer grids, while both material and geometrical nonlinearity are taken into account. The small and big sizes of span length are considered for each type of square grids. The algorithm gets the minimum weight grid by finding the best nodal location in z-direction (height of the structure) and the suitable selection from the list of tube sections available in American Institute of Steel Construction Load and Resistance Factor Design, simultaneously. All examples are optimized with strength and displacement constraints. The numerical results demonstrate the efficiency and robustness of the presented method for solving real-world practical double-layer grids
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