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DCM-Based Bridgeless PFC Converter for EV Charging Application

Authors: Abhinandan Dixit; Karan Pande; Sivanagaraju Gangavarapu; Akshay Kumar Rathore Abstract:  On-board battery chargers (OBC) are a crucial part of electric vehicle (EV) industry. OBC comprises of a two-stage structure where front-end converter is a power factor correction (PFC) unit and a back-end DC-DC converter which controls the battery charging process. The front-end converter is the most complex part of the battery charger in terms of control and design. This paper proposes a single-phase switched-mode bridgeless ac-dc buck-boost derived converter that can serve as a front-end converter for the on-board EV charging application. The bridgeless scheme rules out the orthodox bridge rectifier and the affiliated losses. The proposed converter operates in discontinuous current conduction mode (DCM), thus achieving natural power factor correction for variable ac input. In addition to this, sensing of input voltage and input current is fended off because of DCM operation making the converter reliable, cost-effective, and robust compared with conventional continuous current conduction mode converters. Furthermore, the control becomes simple with the employment of a single sensor and the elimination of the phase-locked loop. The proposed front-end converter is well suited for low-voltage battery chargers ranging between 1.0 and 3.3 kW installed in golf-carts and E-rickshaws. A ...
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Isolation barrier design

Gate Drivers for Medium-Voltage SiC Devices

Authors: Anup Anurag, Sayan Acharya, Nithin Kolli and Subhashish Bhattacharya Extended Abstract: Extensive research in wide-bandgap material technology such as silicon carbide (SiC) has led to the development of medium voltage (MV) power semiconductor devices with blocking voltages of 3.3 kV to 15 kV. When these devices are used in various applications, they are exposed to a high peak voltage stress and a very high dv/dt (50 V/ns to 100 V/ns). These impose stringent requirements on the gate driver requiring a high isolation voltage capability along with a high dv/dt ruggedness, which makes it necessary to have an ultra-low coupling capacitance between primary and secondary sides of the isolated gate driver power supply. One of the key issues in achieving this MV isolation pertains to the necessary clearance and creepage requirements, as defined in IEC 61800-5-1 standards. For the successful operation of these gate drivers to be demonstrated in MV converter applications such as Solid-State Transformers [SST], MV grid-connected converters, and MV motor drives, substantial research to improve the gate drivers' performance and provide a plug-and-play solution is needed. This work aims to comprehensively review and develop these gate drivers and consolidate various required design features concerning their galvanic isolation ...
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A Comprehensive Review of the Integration of Battery Energy Storage Systems Into Distribution Networks

Authors: Marco Stecca; Laura Ramirez Elizondo; Thiago Batista Soeiro; Pavol Bauer; Peter Palensky Abstract: Recent developments in the electricity sector encourage a high penetration of Renewable Energy Sources (RES). In addition, European policies are pushing for mass deployment of Electric Vehicles (EVs). Due to their non-controllable characteristics, these loads have brought new challenges in distribution networks, resulting in increased difficulty for Distribution System Operators (DSOs) to guarantee a safe and reliable operation of the grid.  Battery Energy Storage Systems (BESSs) are promising solutions for mitigating the impact of the new loads and RES. In this paper, different aspects of the BESS's integration in distribution grids are reviewed. At first, the physical layer will be considered, focusing on the main battery technologies commercially available and on the power electronics converter. Secondly, the different functionalities that a grid-connected BESS can provide will be investigated, and then its sizing, location and control in distribution network will be discussed. In addition, an overview of actual BESSs installations is given. All in all, this paper aims at providing a comprehensive view of BESSs integration in distribution grids, highlighting the main focus, challenges, and research gaps for each one of these aspects. Published in IEEE ...
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A Simple Technique for Fundamental Harmonic Approximation Analysis in Parallel and Series-Parallel Resonant Converters

Authors: Akshay Kumar Rathore, Senior member IEEE, and Venkata R Vakacharla, student member IEEE Abstract The Fundamental Harmonic Approximation (FHA) analysis favored engineers by alleviating obstacles in analysis, loss computation, and optimization by reducing complex resonant converter into a mere Resistance-Inductance-Capacitance (RLC) circuit. However, to improve the power density of an X-ray machine power supply, elimination of filter inductor leaves parallel and series-parallel resonant converters with capacitive filter in output, which forces the Rear End Rectifier (RER) to draw discontinuous currents. These unprecedented discontinuous currents through resonant tanks complicate the FHA analysis, a simple and elegant approach, by forcing it to adopt computer-aided techniques and numerical methods similar to the time domain, state-space, and state-plane approaches. Therefore, all available tools, including traditional FHA, fail to model these converters with reduced complexity and labor. Addressing this issue, this paper presents a technique to restore the simplicity of FHA analysis in the case of parallel and series-parallel resonant converters terminated with capacitive filters. The authenticity, simplicity, and accuracy of the proposed technique are demonstrated through results. Further, a detailed comparison with existing modeling techniques is also provided. This paper is published in IEEE Transactions on Industrial Electronics Check full paper at: ...
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Small-Signal Modeling and Closed-Loop Control of a Parallel–Series/Series Resonant Converter for Wireless Inductive Power Transfer

Authors: Suvendu Samanta ; Akshay Kumar Rathore Abstract: Usually, the parallel-compensated inductive power transfer (IPT) topology fed by a current-source inverter is controlled through variable switching frequency and fixed 50% duty cycle method. This enables the system to operate at resonance frequency, which drifts due to load and other parameter variations. Owing to this control constraint, the load requirements are fulfilled by adding extra dc-dc chopper at the output. This paper presents a new control technique for a parallel-series/series IPT network, fed from a full-bridge current-source inverter to meet the load demand directly by an inverter. Therefore, the extra chopper stage at the output side of the converter is eliminated. The control goals are achieved through a two-loop control method, where the inner input current loop controls the source current and the outer output current loop meets the load requirements. The detailed steady-state operation, converter design, small-signal modeling, and control are reported, and experimental results obtained from a 1.6-kW lab prototype are included to verify the mathematical analysis. This paper is published in IEEE Transactions on Industrial Electronics Check full paper at: https://ieeexplore.ieee.org/document/8331928 ...
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