Battery Load Research Articles

An Efficient Inductive Power Transfer Topology for Electric Vehicle Battery Charging

Recently available high-frequency power converter topologies for inductive power transfer (IPT) system utilize either zero voltage switching (ZVS) or zero current switching (ZCS) based power electronic converters while maintaining a near sinusoidal current for limited power transfer range. However, achieving ZVS or ZCS for all power switches simultaneously is still a challenging task in IPT systems. In this article, an improved zero-voltage zero-current switching (ZVZCS) IPT topology and its switching pattern are proposed. ZVS is achieved by optimizing the classical series compensation and additionally, an auxiliary network is employed to achieve ZCS. The proposed concept is verified by using MATLAB/Simulink based simulations for resistive and battery load. Finally, the practical viability of the proposed topology is validated by the results obtained using a laboratory prototype rated for 1.1 kW, 85 kHz. An efficiency of 91.26% is achieved with ZVZCS for a full dynamic power transfer range of 20 W–1.1 kW.

The risk analysis of the electrical Cross-tie for extended Station Blackout in Multi-Unit site

The SBO is defined as the events of Loss of Offsite Power (LOOP) combined by loss of dedicated Emergency Diesel Generators(EDGs) for each unit. The SBO can be also extended when the shared Diesel Generator (AAC-DG) is lost additionally. The Electrical Cross-tie (ECT) is the concept of sharing other unit’s dedicated EDG to the unit under extended SBO in the multi-unit NPP site. We re-evaluate the risk of the extended SBO with the ECT option in Single Unit PRA considering Multi-Unit Features. To get a more realistic estimation of Core Damage Frequency (CDF), we developed the KU-PRA model using the AIMS-PSA code. We examined the factor of redundancy of the AC sources on the CDF by adding additional EDGs to the reference KU-PRA Model. We developed methodology and modeling of the Electrical Cross-tie for Multi-units PRA considering Common Cause Failure, Human Reliability Analyses, Battery load shedding, and Occupancy factor.

Battery Parameter Identification Based on Wireless Power Transfer System With Rectifier Load

This article presents battery parameter identification methods considering a rectifier and battery load in wireless power transfer (WPT) systems. In order to reduce the cost and complexity brought by the wireless communication, the load parameters are usually identified through WPT primary side measurement to control the system. Compared with the conventional methods, battery state estimation and load parameter identification are achieved in this article based on only one measured WPT primary side variable. First, the WPT equivalent load is quantitatively expressed, which contains both resistance and inductance components. Then, identification methods for the battery voltage and equivalent resistance are proposed. Meanwhile, selection criteria for the primary side variables are studied to achieve a simple process and high accuracy. Furthermore, a WPT prototype is developed, and the experimental results prove the effectiveness of the equivalent load analysis and the proposed identification methods under the conditions of both battery voltage change and phase shift angle variation. Additionally, the robustness of the proposed methods is studied, considering compensation parameter changes and coil misalignment. Finally, the proposed methods are applied to battery state-of-charge estimation, and the results suggest that the battery power shortage and full charge states can be estimated with high accuracy.

Energy Shaping Control for Wireless Power Transfer System in Automatic Guided Vehicles

This paper proposes an energy shaping controller of a DC/DC converter for automatic guided vehicles (AGVs) wireless power transfer (WPT). A transformer is inserted after the LCC topology to improve the transfer power, and the DC/DC boost converter is added before this topology to obtain desired systematic power dynamically. The system power transfer model is derived based on the idea of voltage transformation and the desired power can be implemented indirectly through regulating desired output voltage of DC/DC converter. With the proposed controller, this WPT system will have a much better dynamic performance and the effective working time can be increased significantly. Furthermore, this paper proposes dynamical regulation strategy for output power to get real time target power according to the charging curve of the battery. Simulation and experimental results verified the control performance of the proposed control scheme. A WPT prototype with power up to 1.65 kW was built, and 92.12% efficiency from DC power source to battery load is achieved, which is 4% higher than that obtained by the conventional PID method.

Space-confined iron nanoparticles in a 3D nitrogen-doped rGO-CNT framework as efficient bifunctional electrocatalysts for rechargeable Zinc–Air batteries

Abstract Transitional metal nitrogen-doped carbon catalysts are increasingly attractive due to their high bifunctional activities in the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) of rechargeable zinc-air batteries. In the present work, space-confined iron nanoparticles in a 3D nitrogen-doped reduced graphene oxide-carbon nanotube (rGO-CNT) framework (Fe-NCNTs/NG) were synthesized by pyrolysis of a compound comprising urea, anhydrous ferric chloride (FeCl3) and ammonium chloride (NH4Cl) in the presence of graphene oxide (GO). Carbon nanotubes (CNTs) were grown from urea under the catalysis of iron before the pyrolysis to obtain Fe-NCNTs/NG. Nitrogen was introduced into the rGO-CNT framework from urea and NH4Cl in the pyrolysis process at a temperature of 700/800/900/1000 °C. XRD, SEM, HRTEM and XPS techniques were employed to characterize Fe-NCNTs/NG and showed iron and/or Fe3O4 nanoparticles are confined in the 3D nitrogen-doped rGO-CNT framework. The electrochemical test results demonstrate that as-prepared Fe-NCNTs/NG can conduct better catalytic performances than Pt/C and IrO2 in the aspects of a higher half-wave potential and a lower overpotential. Specifically, the best catalytic performance of Fe-NCNTs/NG was achieved when it was prepared by a 30:1 mass ratio of urea to FeCl3 and pyrolyzed at a temperature of 900 °C. Furthermore, a home-made zinc-air battery loading a Fe-NCNTs/NG electrode showed better charge-discharge stability and higher power density than a Pt/C loaded zinc-air battery. The present work demonstrates that the Fe-NCNTs/NG framework is promising to be an alternative to Pt/C and/or IrO2 in the rechargeable zinc-air battery industry.

A Hybrid PV-Battery/Supercapacitor System and a Basic Active Power Control Proposal in MATLAB/Simulink

An increase in the integration of renewable energy generation worldwide brings along some challenges to energy systems. Energy systems need to be regulated following grid codes for the grid stability and efficiency of renewable energy utilization. The main problems that are on the active side can be caused by excessive power generation or unregulated energy generation, such as a partially cloudy day. The main problems on the load side can be caused by excessive or unregulated energy demand or nonlinear loads which deteriorate the power quality of the energy networks. This study focuses on the energy generation side as active power control. In this study, the benefits of supercapacitor use in a hybrid storage system are investigated and analyzed. A hybrid system in which photovoltaic powered and stored the energy in battery and supercapacitor are proposed in this study to solving the main problems in two sides. The supercapacitor model, photovoltaic model, and the proposed hybrid system are designed in MATLAB/Simulink for 6 kW rated power. Also, a new topology is proposed to increase the energy storage with supercapacitors for a passive storage system. The instantaneous peak currents energy is aimed to store in supercapacitors temporarily with this topology. The main advantages of this topology are voltage stabilization in two sides by the supercapacitors and a limitation of the battery load, which directly results in longer battery life and decreases the system cost. The simulation results are investigated for this topology.

Three-Port Converter for Integrating Energy Storage and Wireless Power Transfer Systems in Future Residential Applications

This paper presents a highly efficient three-port converter to integrate energy storage (ES) and wireless power transfer (WPT) systems. The proposed converter consists of a bidirectional DC-DC converter and an AC-DC converter with a resonant capacitor. By sharing an inductor and four switches in the bidirectional DC-DC converter, the bidirectional DC-DC converter operates as a DC-DC converter for ES systems and simultaneously as a DC-AC converter for WPT systems. Here, four switches are turned on under the zero voltage switching conditions. The AC-DC converter for WPT system achieves high voltage gain by using a resonance between the resonant capacitor and the leakage inductance of a receiving coil. A 100-W prototype was built and tested to verify the effectiveness of the converter; it had a maximum power-conversion efficiency of 95.9% for the battery load and of 93.8% for the wireless charging load.

Model-Based End of Discharge Temperature Prediction for Lithium-Ion Batteries

Battery fast charging is one of the key techniques that affects the public acceptability and commercialization of electric vehicles. Temperature is the critical barrier for fast charging as at low temperatures an increased risk of lithium plating and at high temperatures safety concerns limits the charging rate. To facilitate a fast charging mechanism, preconditioning the battery and maintaining its temperature is vital. Battery temperature prediction before a fast charging event can help reducing the energy consumption for battery preconditioning. In this paper, we propose a method for battery end of discharge temperature prediction for fast charging purposes. Firstly, a Gaussian mixture data clustering is performed on battery load data characterisation, subsequently a Markov model is trained for load prediction, and finally a battery lumped parameter equivalent circuit and thermal model is developed and employed for end of discharge time and ultimately end of discharge temperature prediction. Cylindrical lithium-ion battery is selected to prove the concept and both simulations and experiments show the capabilities of the proposed method for temperature prediction of batteries under load profiles obtained from real-world drive cycles of electric vehicles.

Development of starter battery load mode

For operational monitoring of the technical condition of the starter battery, it is necessary to know how its parameters change during operation. Detection of battery failures is possible based on a comparative assessment of changes in the output voltage in typical load modes. The purpose of the article is to develop a load mode containing four successive loading stages with variations in the discharge current and loading time. Experimentally, the change in the output voltage of both a working battery and because of simulating characteristic faults has been established. Further research will be aimed at compiling an array of data for the system of rapid diagnostics of starter batteries on-board the vehicle. Keywords starter battery, load mode, discharge current, fault simulation

An Energy Balanced Flooding Algorithm for a BLE Mesh Network

This paper presents a proposal for a balanced flooding protocol for mesh networks over BLE (Bluetooth Low Energy). The primary goal is to save battery lifetime by converting nodes into a mesh network in a balanced mode and thus increasing the lifetime of the network. Based on an extension of the flooding protocol Trickle, the proposed protocol, Drypp, aims to balance the loads of the network nodes. Hence it seeks to make nodes with a higher load more active in the network in comparison to nodes with a lower load. A performance analysis will be executed, comparing the proposed protocol and Trickle. The metrics of node lifetime, network lifetime, throughput and node battery loads will be analyzed.

Power Stability Control Strategy of the WPT System Based on Load Detection

The output power fluctuates when offset occurs between the receiving coil and the transmitting coil or load equivalent impedance changes in a wireless power transfer system (WPT). These two conditions will affect the safety of the system and the life of the battery load. Therefore, effective control methods are needed to ensure the stability of the load power. This paper analyzes the WPT system with LCC/S compensation topology and the secondary side containing DC/DC circuit. The relationship between mutual inductance and load voltage and current, mutual inductance and the system transmission efficiency, DC/DC circuit duty ratio and load voltage and current are deduced. The output power stability control strategy through load voltage and load current detection and control of DC/DC circuit is proposed. Finally, the WPT system with 1 kW output power is built through simulation and experiment, which verifies the effectiveness and correctness of theoretical analysis and control strategy in this paper.

A Global Maximum Power Point Tracking Technique of Partially Shaded Photovoltaic Systems for Constant Voltage Applications

The P–V characteristics of photovoltaic (PV) array exhibit several maximum power points (MPP) during non-uniform insolation (i.e., during partial shading) conditions; there exists only one global MPP (GMPP), whereas others are referred to local MPP. This paper presents a technique to track the GMPP for the constant voltage or battery loads during partial shading conditions using a single sensor connected to the battery terminals. The proposed method introduces fast and efficient scanning based method, i.e., scanning I batt– D curve of power electronic interface at selective duty cycles to recognize the kind of the solar shading pattern (i.e., kind of P–V curve) on PV array and to find the GMPP neighborhood. Moreover, the proposed method overcomes the drawbacks of existing methods such as low convergence speed, increased number of sensors, and heavy computational complexity. The proposed GMPPT method is simulated in MATLAB/Simulink and validated through test results on a prototype for various non-uniform insolation conditions. The results have shown that this paper tracks the GMPP with best tracking efficiency and fast tracking speed. Further, the proposed method is compared with two P–V curve scanning based GMPPT methods and one global optimization based artificial bee colony method.

9 Kw VRFB Experimental Facility: Early Results from a Multichannel Electrochemical Impedance Spectroscopy

A Vanadium redox flow battery test facility of industrial size (IS-VRFB) has been recently built at the Energy Storage and Conversion Laboratory of University of Padua in order to investigate the performance potential of scaling-up from small-scale single-cell bench experiments. The facility is built around a 40-cell 600-cm­ 2 active-area stack and two 550-litre tanks. The facility is provided with advanced electronic bidirectional power supply, multiphysics instrumentation and data acquisition and control system. This paper reports on the commissioning of a multichannel Electrochemical Impedance Spectroscopy (EIS) system, tailored for such large stack, capable of operating in the range 0-30 kHz, with bias currents up to 400 A. Results from early experimental campaign will be also reported, which show the lack of uniformity among cells and how differences enlarge with increasing battery load conditions. Results can be instrumental in addressing the design of flow patterns inside a large stack. References Alotto, M. Guarnieri and F. Moro, “Redox flow batteries for the storage of renewable energy: A review,” Renew Sus. Energ Rev. 29, (2014): 325–335.Guarnieri, A. Trovò, A. D’Anzi, P. Alotto, “Developing vanadium redox flow technology on a 9-kW 26-kWh industrial scale test facility: design review and early experiments”, Appl Energy, 230 (2018) 1425-1434. DOI: 10.1016/j.apenergy.2018.09.021.Trovò, G. Marini, A. Sutto, P. Alotto, M. Giomo, F. Moro, M. Guarnieri, “Standby thermal model of a vanadium redox flow battery stack with crossover and shunt-current effects”, Appl Energy, 240 (2019) 893-906.Trovò, A. Saccardo, M. Giomo, F. Moro, M. Guarnieri, “Thermal modeling of industrial-scale vanadium redox flow batteries in high-current operations”, J Power Sources, in print. Figure 1

Improved Power Quality Switched Inductor CUK Convertor for Variable Speed DC Motor with PIC Microcontroller

In this paper, low current pressure and high productivity with diminished components have been used to get high step down gain. A single-staged switched inductor Cuk converter is used for correcting the power factor, Different parts of the proposed converter are analyzed in continuous current mode (CCM). Operational analysis and design equations are analyzed. The performance analyses of the proposed converter concerning power quality such as voltage total harmonic distortion (THD), current THD and complete power factor are done with different kinds of load, for example, resistive load and battery load at constant voltage (CV) and constant current (CC). It is utilized to drive a DC motor at variable speeds with the assistance of a PIC microcontroller.

Design and Analysis of a New GaN-Based AC/DC Converter for Battery Charging Application

This paper reports on the design, analysis, and characterization of a simple gallium nitride (GaN)-based ac/dc converter for battery charging applications. The proposed converter combines the merits of GaN switching transistors together with the advantages of close-to-unity power factor of a totem-pole power factor corrector, a high-frequency (HF) isolated series resonant converter, and a current doubler rectifier to reduce the copper losses of the HF transformer. The converter is designed to convert a 120 Vac input to a 48 Vdc/60 Vdc output for a 1.5 kW battery load at 65–100 kHz. Its steady-state characteristics are analyzed based on equivalent circuit and state-space models while its frequency characteristics are analyzed using MATLAB simulations. Finally, an experimental prototype is fabricated and characterized.

Self-Oscillating Pulsewidth Modulation for Inductive Power Transfer Systems

This paper presents a new self-oscillating tuning loop for inductive power transfer (IPT) systems using a combination of phase shift and pulsewidth modulations (PS-PWMs). Self-oscillating methods are the uncertainty-tolerant solution for power and frequency control of resonant converters. However, constant duty-cycle operation affects their effectiveness with extra dc-link current ripples and losses. In this paper, PS-PWM is achieved by instant phase displacement controlling between the two legs of the inverter, which guarantees zero voltage switching (ZVS) for transients and light-load conditions. The presented solution simultaneously integrates PWM and PS switching methods with a fast dynamic response even under nonlinear conditions, e.g., battery loads, and sudden load changes. In the presented work, an optically controlled phase shifter is proposed, which has a simple structure and smoother phase regulation in comparison with digital potentiometers. Moreover, this paper analyzes the behavior of the proposed method in bifurcation condition and shows the reliability and stable operating area of the system. To show the feasibility of the presented switching technique, a prototype is implemented based on series–series (SS)-compensated topology and investigated for different operating frequencies and loads.

Design and Development of Microcontroller Battery Filling Control System Arm Cortex M0-Nuc 120 on Axial Axis Wind Turbine Type

Indonesia is an archipelago and one country located on the equator with abundant wind energy potential. Various studies of wind turbine models are used to study electric power systems. This development is based on various research focuses such as turbine propellers, wind speed, and electrical charging coefficients. So that in this study there is a need to design a charger controller to charge a 6 Volt battery load, 4.5 Ah on the axial axis mini wind turbine type plant. In this charger contoller circuit is composed of 2 circuits namely the boost converter circuit using a 3.2 mH inductor and power IRFP460 MOSFET and pulse signal generator range PWM (Pulse With Modulation) and 4N35 Optocoupler IC and ARM CORTEX M0-NUC 120 Microcontroller. The method used is through preliminary observation, problem identification, literature study and field studies, determining parameters and data collection. From the results of the charger controller trial results obtained an average output voltage of this controller is ± 6 volts, which has adjusted the voltage specifications to charge the 6 volt battery and the resulting current is an average of 0.02 amperes. With a frequency of 1.25 KHz and a duty cycle of 70%. The highest charger controller efficiency occurs at 7 m/s wind speed with an efficiency value of 3%. The design of the charge controller that has been made for the output voltage of the DC 1-4V generator which will be increased by the boost converter with the input voltage value of 6-7 volts to meet the charge voltage for the battery battery 6V, 4.5Ah, the output variable of the generator DC is controlled by the charge controller using the switching method. The battery charging control system using this auto cut off circuit works when the Depth of Discharge voltage of the 6 V battery is 50% at a measured voltage of 6.12 V and the charging process stops when the voltage reaches 6.05 V.

Combined electrical and electrochemical-thermal model of parallel connected large format pouch cells

Abstract Variation in energy capacity and resistance of cells connected in parallel can degrade the overall performance of the energy storage system (ESS). Such variations can lead to significant individual differences in battery load current, state of charge (SOC) and heat generation. An experimentally validated 1D electrochemical-thermal model of a large format 53 Ah pouch cell is employed to underpin the performance evaluation of parallel connected cells within the context of a complete ESS. The cell model, developed within COMSOL Multiphysics is coupled with an electrical circuit model of the ESS within Matlab. Results are presented that quantify cell-to-cell differences in load current and heat generation as the length of the parallel connection and value of the cell interconnection resistance is varied. The results highlight that variations in cell depth of discharge and the occurrence of temperature gradients across the parallel connection increases at higher load currents and interconnect resistances. The impact is amplified as the length of the parallel connection increases which will accelerate cell ageing and, if unmanaged, may present safety concerns.

Reconfigurable Low Voltage Direct Current Charging Networks for Plug-In Electric Vehicles

An emerging theme in the development of supporting facilities for plug-in electric vehicles (EVs) is the cost-effective planning and utilization of charging networks consistent with the uptake of EVs. This paper proposes a low voltage direct current reconfigurable charging network for plug-in EVs and presents a functional energy management system (EMS) that is capable of planning and operating the charging network to minimize cost and to facilitate progressive infrastructure deployment based on EV demand. The charging network is connected to the main ac grid through one or more centralized ac/dc converters that supply a high power charge to EVs connected to the dc side of the converters. The EMS accommodates multiple parking bays, charging sources, ac constraints, non-linear EV battery loads and user charging requirements with a novel approach to managing user inconvenience. The inconvenience model is founded on the presence of user flexibility, i.e., an allowance on charging time or battery SoC, providing the capability to increase asset utilization and enable access for additional network users. Through a series of case studies and a stochastic forecasting approach, the reconfigurable network and EMS demonstrate the capacity to achieve savings over fixed ac and sequential dc systems.

Improved Power Quality Switched Inductor Cuk Converter for Battery Charging Applications

Most of the two-stage converters for electric bike battery charging comprise of a boost converter for power factor correction (PFC) followed by a dc–dc converter with universal input voltage. These two-stage conversions suffer from poor efficiency and increased component count. In this paper, a single-stage switched inductor Cuk converter based PFC converter is proposed, which offers high step-down gain, low current stress, high efficiency, and reduced component count. The operational analysis and design equations for various components of the proposed converter are carried out in continuous current mode. This paper presents mathematical modeling, analysis, simulation, and experimentation on the proposed converter rated for 500 W, 48 V/10.4 A. The performance investigation of the proposed converter with respect to power quality indices like voltage total harmonic distortion (THD), current THD, and total power factor is carried out with various types of loads such as resistive load and battery load in both constant voltage (CV) and constant current (CC) mode. Furthermore, the dynamic performance of the proposed converter with battery charging is investigated in CV mode and CC mode with respect to the wide range of supply variations.