Faculty Publications
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Item Development of Small Signal Model and Stability Analysis of PV-Grid Integration System for EV Charging Application(Institute of Electrical and Electronics Engineers Inc., 2024) Kanimozhi, K.; Koothu Kesavan, K.K.; Nagendrappa, N.; Balasubramanian, B.In this article, grid interactive photovoltaic (PV) system is designed for an electric vehicle (EV) charging application, and the stability of the system is analyzed. The small signal model for the system is derived by averaging and linearizing the state space equations, and the condition for stable operation of PV-integrated charger system is identified from the transfer functions. The proposed charger system implements a coordinated control between the converters to maintain a power balance between the sources and load. System stability is examined using root-locus plots and in addition, the controller is designed to improve the overall stability and reliability of the system. The proposed method provides a general framework for modeling EV charging systems which also details the importance of deriving the model with multiple energy sources. Further, proposed topology has bidirectional capability, which transfers excess PV power to the grid during off-charging hours. The efficacy of the proposed method is verified using the MATLAB Simulink environment for the different scenarios, i.e., variation in the irradiation and disturbances in the grid voltage. The experimental study is conducted on a 1.5-kW laboratory prototype using a low-cost digital signal processing controller (launchpad TMS320F28027F) and the measured results authenticate the simulation findings. © 2020 IEEE.Item An Integrated Onboard EV Charger With Wide Voltage Range Compatibility(Institute of Electrical and Electronics Engineers Inc., 2025) Kumar, V.; Prabhakaran, P.; Reddy, B.D.; Febin, J.L.F.Electric vehicles (EVs) typically employ separate onboard chargers and traction inverters for battery charging and motor operation, respectively. This paper proposes a bidirectional integrated onboard charger (BIOC) that utilizes a single power converter to perform both functions, thereby reducing cost, improving system compactness, and supporting fast charging. The proposed BIOC architecture is implemented using a totem-pole power factor correction (PFC) stage combined with an additional coupling unit. This configuration supports a wide range of battery voltages and is compatible with both AC and DC grid inputs. The BIOC incorporates active power decoupling (APD) to minimize voltage ripple at the battery terminals during high-voltage (HV) battery charging. Leakage current analysis of the totem-pole PFC stage confirms compliance with safety standards, and a detailed switch loss calculation procedure is presented. A comprehensive controller design is developed using State-Space Averaging (SSA) and Small Signal Modelling (SSM), followed by a K-factor method to ensure optimal performance across various operating modes. The proposed system is validated through simulations on a 2 kW Simulink model and experimental testing on a 400 W scaled-down prototype, demonstrating effective charging of an EV battery across a wide voltage range from both AC and DC grids. This work offers a unified, efficient, and cost-effective solution for integrated onboard EV charging. © 2013 IEEE.Item Design and Laboratory Validation of a Grid-Interfaced Totem-Pole PFC Converter With PR Controller and Isolated Phase Modulated Converter for Solar-Powered Next-Gen EV Charging System(China Power Supply Society, 2025) Kanimozhi, K.; Kesavan, P.K.; Nagendrappa, N.; Balasubramanian, B.This paper proposes a stationery reference frame proportional-resonant (PR) controller for current control of grid-tied converters in an EV charger application. Since it is a viable alternative to rotational reference frame PI compensators in AC applications, the PR controller has been adopted for achieving zero steady state error without using any computationally intensive reference frame transformations. In this paper, a method to design the structure of PR controller and its coefficients according to the desired transient behaviour of AC signal amplitude in PFC converter current loop has been proposed. The importance of suggested PR controller design method is that the grid current magnitude is varying constantly based on the available PV power and battery charger levels which necessitates the controller to act in desired transient behaviour. So, by this way the impact of variation in system parameters have been completely overcome by operating the converter controllers appropriately in a solar powered EV charger system. To verify the effectiveness of the proposed controller design, extensive simulations and experimental studies are performed in a 1.5 kW EV charger system under various PV irradiances and charger power levels. The experimental results obtained from the laboratory prototype confirms the simulation findings. © 2025 China Power Supply Society. All rights reserved.Item Implementation of Coordinated Control and Power Flow Management Strategy for a Solar Powered EV Charging System(Institute of Electrical and Electronics Engineers Inc., 2025) Kanimozhi, K.; Koothu Kesavan, P.; Nagendrappa, N.; Balasubramanian, B.This paper introduces a novel coordinated control and power flow management strategy (CC-PFMS) for a solar integrated electric vehicle (EV) charging system. The CC-PFMS is designed to have inherent power balance capability under various operating modes with multiple energy resources. Further, it will facilitate the direction of power flow from grid to battery or vice versa irrespective of the charger system dynamics. The main advantage of proposed strategy is to identify different conditions such as change in solar irradiance, vehicle availability and battery charging/discharging state and ensure the stable operation. The veracity of the new approach is tested on 1.5 kW charger system having photovoltaic (PV) source integrated with utility grid. The performance of CC-PFMS under various operating modes viz. grid to vehicle (G2V), vehicle to grid (V2G), PV to vehicle (PV2V), PV to grid (PV2G), G2V+PV2V, V2G+PV2G and PV2V+PV2G is substantiated through extensive MATLAB simulations. The experiments were also performed in the laboratory prototype to confirm the simulation findings and recorded results were presented. © 1975-2011 IEEE.Item Novel Reconfigurable Power Converters Facilitating Dual Battery Integration in Electric Vehicles(Institute of Electrical and Electronics Engineers Inc., 2025) Kumar, V.; Prabhakaran, P.; Raj, N.Battery-operated Electric Vehicles (EVs) are experiencing a significant surge in demand in today's market. The primary obstacles to the growth of the EV industry include concerns about range anxiety and reliability. To address these challenges, Dual battery-based solutions are emerging as a recent trend in the EV, specifically the two-wheeler segment. This paper introduces two novel reconfigurable power converters that enable dual battery integration. The converters can connect the dual batteries in series or in parallel or allow using a single battery during traction or charging. The output terminals of the converters can be directly connected to the charger or traction inverter. To connect dual batteries in parallel with minimum circulating currents, the terminal potentials must be nearly equal. The proposed converters include a voltage balancing feature to ensure this balance. To demonstrate dual battery charging, the proposed converter is integrated into a non-isolated inverter charger system (ICS). Transfer functions for the system with the proposed converter have been derived using state space averaging and small signal modeling, and the necessary controllers have been designed using the K-factor approach. Comprehensive MATLAB simulations and hardware experiments are presented to validate the effectiveness of the proposed power converters. © 1972-2012 IEEE.