Variations in cell properties are unavoidable and can be caused by manufacturing tolerances and usage conditions. As a result of this, cells connected in series may have different voltages and states of charge that limit the energy and power capability of the complete battery pack. Methods of removing this energy imbalance have been extensively reported within literature. However, there has been little discussion around the effect that such variation has when cells are connected electrically in parallel. This work aims to explore the impact of connecting cells, with varied properties, in parallel and the issues regarding energy imbalance and battery management that may arise. This has been achieved through analysing experimental data and a validated model. The main results from this study highlight that significant differences in current flow can occur between cells within a parallel stack that will affect how the cells age and the temperature distribution within the battery assembly.

Dataset to support article: 'Modelling and experimental evaluation of parallel connected lithium ion cells for an electric vehicle battery system'

Pulse width modulation (PWM) is a powerful technique employed in analog circuit convert with a microprocessor based digital output. Besides, Pseudo Random Multi Carrier (PRMC) involves in two random PWM strategies to minimize the harmonic order for 9- level cascaded multilevel H-bridge (CHB) inverter and 9-level Modular Multilevel inverter are introduced. The design mainly focuses on the (Pulse Width Modulation) PWM method, in which two nearest voltage levels are approached in estimated output voltage prediction based on the Partial swarm optimization (PSO) algorithm, and it conveys a random variation in the pulse position of output by Pseudo Random Multi Carrier- Pulse Width Modulation (PRMC-PWM). The CHB and the Modular inverters generate low distortion output by using PMRC. The simulation and prototype circuit are developed for the nine level output using sixteen switches and ten with Resistive-Inductive (R-L) load variation condition. The power quality is improved in CHB and Modular inverter (MoI) with minimized harmonics in various modulation index (MI) as varied from 0.1 up to 0.8. The circuit is designed by using a Field Programmable Gate Array (FPGA), Implementing a PSO algorithm for both CHB, and MoI are proposed. The comparisons of results are verified with lower order harmonics and find the best switching angle across the MLI switches. Modular inverter furthermore investigates with PRMC, Random Nearest level (RNL) modulation scheme are presented, and the proposed circuit is along with the respective degree of the output voltage were synthesized in non-linear load by the development of reactive power across a motor load.

https://www.ejece.org/index.php/ejece/article/download/315/189

Power Quality Improvement in Modular Multilevel Inverter Using for Different Multicarrier PWM

A Voltage lift performance is an excellent role to DC/DC conversion topology. The Voltage Lift Multilevel Inverter (VL-MLI) topology is suggested with minimal number of components compared to the conventional multilevel inverter (MLI). In this method, the Modified Particle Swarm Optimization (MPSO) conveys a primary task for the VL-MLI using Half Height (H-H) method, it determine the required optimum switching angles to eliminate desired value of harmonics. The simulation circuit for fifteen level output uses single switch voltage-lift inverter fed with resistive and inductive loads (R &amp; L load). The power quality is developed by voltage-lift multilevel inverter with minimized harmonics under the various Modulation Index (MI) while varied from 0.1 up to 1. The circuit is designed in a Field Programmable Gate Array (FPGA), which includes the MPSO rules for fast convergence to reduce the lower order harmonics and finds the best optimum switching angle values. To report this problem the H-H has implemented with MPSO to reduce minimum Total Harmonic Distortion (THD) for simulation circuit using Proteus 7.7 simulink tool. Due to the absence of multiple switches, filter and inductor element exposes for novelty of the proposed system. The comparative analysis has been carried-out with existing optimization and modulation methods. 

Design and experimental investigation on VL-MLI intended for half height (H-H) method to improve power quality using modified particle swarm optimization (MPSO) algorithm

To minimize real-time errors in a Photovoltaic (PV) system performances must be forecasted through precise simulation design before continuing into a practical application. However, due to the scarcity of data in datasheets and the inherent transcendental connections are between PV current and PV voltage, to determining the Single Diode Model (SDM) parameters becomes a more challenging problems. This paper offers a simulated study of a SDM and Double Diode Model (DDM) solar PV system under various irradiation represents, and the performance was developed by incorporating an optimization-based Maximum Power Point (MPP) tracking techniques. According to the present simulation presented in this article, a mathematical model for a SDM/DDM as well as optimization methodologies has been estimated MATLAB platform. The present MPP circuit model designed and compared with BAT optimization algorithms. The nonlinear relationship between Voltage (V) - Current (I) and Voltage (V) –Power (W) acknowledged as characteristic curves for different temperature (∘c) and irradiance (W/m2) values are verified in numerical simulation results. MPP tracking power and efficiency are examined for maximum power (Pmax) to test the optimization based system. The simulation results show that the BAT optimization model was achieved the highest tracking efficiency better than other heuristic algorithms.

Design and development of extract maximum power from single-double diode PV model for different environmental condition using BAT optimization algorithm

An Experimental Investigation on solar PV fed modular STATCOM in WECS using Intelligent controller

The demand for sustainable energy has increased significantly over the years due to the rapid depletion of fossil fuels. The solar photovoltaic system has been the advantage of converting solar irradiation directly to electricity, and it is suitable for most of the regions. But in the case of solar energy conversion, the voltage evolved from the solar photovoltaic cells is not adequate to meet the energy demand. Therefore, the converters and inverters with energy storage systems are used to fulfill the energy demand. These conversion architectures create new challenges for effective management of the grid. Due to the evaluation of power generation, load in a particular region or area, let us simplify with the help of the duck curve. The study is focused on the energy auditing, assessment, and measurement of solar irradiation from PV system design software. This graphical representation is implemented with a typical electricity load pattern at any region.

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Solar Energy Assessment in Various Regions of Indian Sub-continent

A novel PV fed asymmetric multilevel inverter with reduced THD for a grid-connected system

Grid integration of modular multilevel inverter with improved performance parameters

This article discussed the development of a solar photovoltaic-fed modular multilevel inverter (MMI) with reduced switch count to operate an asynchronous motor drive for maritime applications. The proposed marine water-pumping system consist of a PV panel, an asynchronous motor drive, and modular inverter. The suggested topology can produce 11 levels of output using asymmetric DC sources. The proposed MMI consists of five DC sources, and they are powered by the PV panels. The primary advantage of the proposed topology is that it does not need any auxiliary circuit to produce the negative levels. Moreover, the active sources (PV panels) in the proposed system are reduced by implementing a modified single-input and multiple-output SEPIC converter. The power consumption by on-board pumping systems in maritime is estimated to be almost 50% of the total power. Taking this into account, this article investigates an adaptive fuzzy logic-based closed-loop control design for reducing the losses in the induction machine and thereby improving the efficiency of the system. Further, the performance of the proposed system is compared with the conventional PI controller, and from the results, it is proved that the proposed control system works effectively in reducing the losses as well as improving the efficiency of the system. The simulations are carried out in MATLAB/Simulink, and the experimental investigations are carried out in the laboratory. The obtained experimental results are similar to the simulation results.

Dishore Shunmugham Vanaja

Papers

Solar Energy Assessment in Various Regions of Indian Sub-continent

An Experimental Investigation on solar PV fed modular STATCOM in WECS using Intelligent controller

A novel PV fed asymmetric multilevel inverter with reduced THD for a grid-connected system

Grid integration of modular multilevel inverter with improved performance parameters

Investigation and validation of solar photovoltaic-fed modular multilevel inverter for marine water-pumping applications