N. Lakshmi Narasamma

Bio: N. Lakshmi Narasamma is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Maximum power point tracking & Photovoltaic system. The author has an hindex of 6, co-authored 11 publications receiving 288 citations.

Design and Analysis of Novel Control Strategy for Battery and Supercapacitor Storage System

Abstract: In this paper, a simple novel control strategy is designed and analyzed for a hybrid energy storage system (HESS). In the proposed method, batteries are used to balance the slow changing power surges, whereas supercapacitors (SC) are used to balance the fast changing power surges. The main advantage of the proposed control strategy is that, the slow response of battery system including dynamics of battery, controller, and converter operation, is overcome by diverting the power surges to the SC system. The proposed method inherits charge/discharge rate control to improve the life span and reduce the current stresses on battery. The proposed method features less computational burden as it uses simple control strategy. The detailed experimental results presented validate the proposed control strategy for sudden changes in photovoltaic (PV) generation and load demand.

An Improved Digital Algorithm for Boost PFC Converter Operating in Mixed Conduction Mode

Abstract: This article proposes an improved digital algorithm based on predictive control for the operation of a boost power factor correction (PFC) converter in the mixed conduction mode (MCM). The proposed MCM algorithm comprises of a proposed digital conduction mode detection method, a proposed predictive discontinuous conduction mode (DCM) average current controller, a proposed digital compensation technique in DCM to account for the initial nonzero inductor current during switch turn-on and also a predictive continuous conduction mode (CCM) average current controller. The proposed algorithm flow is computationally efficient with no additional sensor/circuit requirements and ensures low harmonic content in the input current. The proposed MCM algorithm is verified experimentally on a 300-W boost PFC converter hardware prototype for converter operation in MCM, pure DCM, and pure CCM within a half line cycle. The proposed MCM algorithm is evaluated experimentally in terms of current tracking, current harmonics, and computation times.

A new control strategy for interfacing battery supercapacitor storage systems for PV system

Abstract: In this paper, a new control strategy is proposed for hybrid energy storage system (HESS) for remote area power supply system consisting of PV, battery, supercapacitor (SC) and load. Since the PV generation and load demand varies continuously, batteries can undergo irregular, partial charge/discharge cycles. It has detrimental effects on battery life span and rating. Therefore in the proposed method, batteries are used to balance the low frequency power surges, because of its low power density and low charge/discharge rates. Whereas SCs are used to balance the high frequency power surges, because of its high power density and high charge/discharge rates. The control of the battery system is coordinated with SC to improve the life span and reduce the stress on battery. The proposed control strategy is compared with the conventional strategy and validated for sudden changes in PV generation and load demand through digital simulation.

A New Isolated Auxiliary Current Pump Module for Load Transient Mitigation of Isolated/Nonisolated Step-Up/Step-Down DC–DC Converter

Abstract: This paper presents a new isolated auxiliary current pump module (ACPM), to improve the dynamic response of dc–dc converters under load transients. The developed isolated ACPM can be used as a generic auxiliary module for both isolated and nonisolated step-up/step-down dc–dc converters. The isolated ACPM is a low-power bidirectional converter, designed with higher bandwidth and operates only during the load transients. The performance of the developed auxiliary power converter has been evaluated in conjunction with an interleaved boost converter as main converter, which suffers from poor dynamic performance due to inherent right half plane zero effect. A suitable control scheme is designed and implemented for interleaved boost converter operating in conjunction with proposed isolated ACPM. Load current injection circuit employed in the proposed control scheme eliminates the requirement of complex nonlinear control algorithms. The proposed control scheme in particular suits for current-mode controlled converters operating along with isolated ACPM. Experimental results for a 250-W 100-kHz interleaved boost converter prototype with ACPM are presented. The peak overshoot/undershoot and the transient recovery time are reduced significantly with the incorporation of developed isolated ACPM.

A single stage high gain buck-boost inverter with coupled inductor

Abstract: Output dc voltage from Fuel Cell (FC)/Photo Voltaics (PV) needs to be conditioned and converted into ac form before integrating to grid Normally, two stage converters are used for this purpose Two stage converters have several disadvantages like low efficiency, more number of components, big size, etc especially when they are operated at low input voltages In this paper, a coupled inductor based high performance, high gain, single-stage inverter topology, which can be used for grid connected FC/PV applications or stand-alone applications is proposed In the proposed topology, dc-dc power conversion and dc-ac power conversion can be done in a single stage The proposed topology has several features such as high gain, low cost and compact size This topology suits well for low power applications The principle of operation, steady state analysis of the proposed topology is presented in this paper The steady state analysis is verified by a simulation, simulation results of the proposed converter for an ac load is presented

Hybrid energy storage system for microgrids applications: A review

Abstract: Energy storages introduce many advantages such as balancing generation and demand, power quality improvement, smoothing the renewable resource’s intermittency, and enabling ancillary services like frequency and voltage regulation in microgrid (MG) operation. Hybrid energy storage systems (HESSs) characterized by coupling of two or more energy storage technologies are emerged as a solution to achieve the desired performance by combining the appropriate features of different technologies. A single ESS technology cannot fulfill the desired operation due to its limited capability and potency in terms of lifespan, cost, energy and power density, and dynamic response. Hence, different configurations of HESSs considering storage type, interface, control method, and the provided service have been proposed in the literature. This paper comprehensively reviews the state of the art of HESSs system for MG applications and presents a general outlook of developing HESS industry. Important aspects of HESS utilization in MGs including capacity sizing methods, power converter topologies for HESS interface, architecture, controlling, and energy management of HESS in MGs are reviewed and classified. An economic analysis along with design methodology is also included to point out the HESS from investor and distribution systems engineers view. Regarding literature review and available shortcomings, future trends of HESS in MGs are proposed.

Emergence of hybrid energy storage systems in renewable energy and transport applications – A review

Abstract: The idea of Hybrid Energy Storage System (HESS) lies on the fact that heterogeneous Energy Storage System (ESS) technologies have complementary characteristics in terms of power and energy density, life cycle, response rate, and so on. In other words, high power ESS devices possess fast response rate while in the contrary, high energy ESS devices possess slow response rate. Therefore, it may be beneficial to hybridize ESS technologies in the way that synergize functional advantages of two heterogeneous existing ESS technologies As a consequence, this hybridization provides excellent characteristics not offered by a single ESS unit. This new technology has been proposed and investigated by several researchers in the literature particularly in the fields of renewable energy and electrified transport sector. In this context and according to an extensive literature survey, this paper is to review the concept of the HESS, hybridization principles and proposed topologies, power electronics interface architectures, control and energy management strategies, and application arenas.

Battery-supercapacitor hybrid energy storage system in standalone DC microgrids: areview

Abstract: Global energy challenges have driven the adoption of renewable energy sources. Usually, an intelligent energy and battery management system is deployed to harness the renewable energy sources efficiently, whilst maintaining the reliability and robustness of the power system. In recent years, the battery-supercapacitor based hybrid energy storage system (HESS) has been proposed to mitigate the impact of dynamic power exchanges on battery's lifespan. This study reviews and discusses the technological advancements and developments of battery-supercapacitor based HESS in standalone micro-grid system. The system topology and the energy management and control strategies are compared. The study also discusses the technical complexity and economic sustainability of a standalone micro-grid system. A case study of a standalone photovoltaic-based micro-grid with HESS is presented.

A Bidirectional Nonisolated Multi-Input DC–DC Converter for Hybrid Energy Storage Systems in Electric Vehicles

Abstract: To process the power in hybrid energy systems using a reduced part count, researchers have proposed several multiinput dc–dc power converter topologies to transfer power from different input voltage sources to the output. This paper proposes a novel bidirectional nonisolated multi-input converter (MIC) topology for hybrid systems to be used in electric vehicles composed of energy storage systems (ESSs) with different electrical characteristics. The proposed converter has the ability to control the power of ESSs by allowing active power sharing. The voltage levels of utilized ESSs can be higher or lower than the output voltage. The inductors of the converter are connected to a single switch; therefore, the converter requires only one extra active switch for each input, unlike its counterparts, hence resulting in reduced element count. The proposed MIC topology is compared with its counterparts concerning various parameters. It is analyzed in detail, and then, this analysis is validated by simulation and through a 1-kW prototype based on a battery/ultracapacitor hybrid ESS.

Hybrid energy storage systems and control strategies for stand-alone renewable energy power systems

Abstract: The energy storage system (ESS) in a conventional stand-alone renewable energy power system (REPS) usually has a short lifespan mainly due to irregular output of renewable energy sources. In certain systems, the ESS is oversized to reduce the stress level and to meet the intermittent peak power demand. A hybrid energy storage system (HESS) is a better solution in terms of durability, practicality and cost-effectiveness for the overall system implementation. The structure and the common issues of stand-alone REPS with ESS are discussed in this paper. This paper presents different structures of stand-alone REPS with HESS such as passive, semi-active, and active HESS. As there are a variety of energy storage technologies available in the market, decision matrixes are introduced in this paper to evaluate the technical and economic characteristics of the energy storage technologies based on the requirements of stand-alone REPS. A detailed review of the state-of-the-art control strategies such as classical control strategies and intelligent control strategies for REPS with HESS are highlighted. The future trends for REPS with HESS combination and control strategies are also discussed.