Multi-Stage Fast Charging Technique for Lithium Battery in Photovoltaic systems

In renewable energy resources such as photovoltaic (PV) systems, fast charging is an emerging case for the battery charger. In this paper, constant-current (CC) and constant-voltage (CV) charging scheme has been studied since it has the highest possible reliability for lithium based batteries. In this work a new charging technique to expedite charging time is proposed. This is a multi-stage technique which improves the threshold voltage detection during CC-stage. Thus the transition to CV-stage occurs accurately at the knee voltage. The novelty of the proposed technique is in the charging algorithm. An experiment was setup based on PIC18f4520 microcontroller. The performance of the proposed technique and the conventional CC-CV Li-ion battery charger has been compared. The result of the proposed technique shows that there is 20% improvement in charging time compared to the conventional CC-CV Li-ion battery charger. © 2022 IEEE

High-current integrated battery chargers for mobile applications

Battery charging circuits for mobile applications, such as smart phones and tablets, require both small area and low losses. In addition, to reduce the charging time, high current is needed through the converter. In this work, exploration of the Buck, the 3-Level Buck and the Hybrid Buck converter is performed over the input voltage, the total FET area and the load current. An analytical loss model for each topology is constructed and constrated by experimental results. In addition, packaging and bond wire impact on on-chip losses is analyzed by 3D modeling. Finally, a comparison between the topologies is presented determining potential candidates for a maximum on-chip loss of 2 W at output voltage of 4 V and 10 A of output current

VeloElectric: Creating a Device that Harvests Energy From Bicycles

Long distance mountain bikers, bike-packers, and many bikers in developing countries rely on electrical devices for safety and communication. These specific groups of people operate in areas with little to no electricity, and often times have no power to sustain their devices. The purpose of this Cal Poly senior project, VeloElectric, was to design, build, and test a kinetic energy harvester for bicycles that can be used to charge common mobile devices via USB. This senior project team created a device that attaches directly to a bicycle and uses vibrations to generate energy, which in turn powers a variety of portable devices. The final product will be used by Professor Lynne Slivovsky on a bike ride from Canada to Mexico. This document contains information on the entire project during the 2014-2015 school year. The “Background” section summarizes research and case studies including dynamo chargers and an electromagnetic induction charger called the nPower PEG. The Pedl team used this information to generate initial design ideas such as using piezoelectrics and other kinetic energy harvesting devices. This research was also used to gain a better understanding of the current state of art for this type of product. The end of the background section provides details of the project management plan that was used through the course of the projects focusing heavily on the tasks completed during Spring quarter. Following the “Background” section is an explanation of the development of conceptual designs that lead to the final product. Conceptual designs included decision matrices to decide on a 3D printed exterior casing, Velcro straps for attachment, electromagnetic induction for energy generation, and a battery for energy storage. Diagrams, models and pictures of the end product are displayed and analyzed in the “Description of Final Design” section. This section shows the exterior casing that was created to house the inner casing, battery, and printed circuit board. The “Product Realization” section focuses on how a lathe was used to create the final inner casing, 3D printing for the exterior casing and inner casing caps, and simple soldering for the electrical components. The section also explains how the final prototype cost the team about $200, but through mass production could be lowered to about$45. The “Design Verification” section discusses how the final iteration was tested and includes test descriptions and photos while documenting the results of these tests. Example tests include weight, bike transfer time, USB compatibility, and vibrational tolerance. The document concludes by discussing the progress that was made on the project throughout the year and the recommendations that the design team has for possible future teams assigned to this task

MPPT battery charge controller with lorawan communication interface

Mestrado de dupla diplomação com Tunisia Private University (ULT Tunisie)Renewable sources, such as Photovoltaic Systems (PV), have been employed for decades to focus on cleaner types of electricity generation. Today, it is a subject of worry as to how to cut costs and enhance efficiency in order to harness and utilise these natural resources in the best way possible. As a result, the concept of Maximum Power Point Tracking Technique (MPPT) evolved, which is essentially a system used by charge controllers for wind turbines and Photovoltaic Systems to use and also give a maximised power output. This thesis is primarily focused with the application of such a system in order to achieve controlled photovoltaic power using the MPPT mechanism. The main goal is to add LoRaWAN capability such as to be able to transmit information regarding the solar charge battery controller internal state A micro-controller, which is part of a larger circuit, such as a solar charge controller, is required for MPPT hardware implementation. The heart of the hardware circuit is the solar charge controller. Furthermore, the system was integrated with a dashboard to provide easier access to data for analysis from anywhere, eliminating the physical work of data collecting.Fontes de energia renovável, como é o caso dos sistemas fotovoltaicos, têm sido vindo a ser cada vez mais utilizadas como alternativas menos impactantes do ponto de vista ambiental. Atualmente, é motivo de preocupação o recurso a métodos e tecnologias que permitam aproveitar os recursos naturais sustentáveis e, ao mesmo tempo, reduzir os custos e aumentar a sua eficiência. Neste contexto, é importante o recurso a técnicas de seguimento de ponto de potência máximo (MPPT), usado por controladores de carga para turbinas eólicas e sistemas fotovoltaicos, de modo a extrair a máxima potência do sistema elétrico de produção de energia. Esta tese assenta no desenvolvimento de um sistema fotovoltaico capaz de regular o processo de carga para baterias de gel, dotada de mecanismo MPPT integrado e com a capacidade de transmitir toda a telemetria associada à operação do regulador usando o protocolo LoRaWAN. Este sistema de controlo de carga é baseado num microcontrolador que implementa o algoritmo MQTT e os dados enviados, via LoRaWAN, são apresentados numa interface gráfica

Advances in Batteries, Battery Modeling, Battery Management System, Battery Thermal Management, SOC, SOH, and Charge/Discharge Characteristics in EV Applications

The second-generation hybrid and Electric Vehicles are currently leading the paradigm shift in the automobile industry, replacing conventional diesel and gasoline-powered vehicles. The Battery Management System is crucial in these electric vehicles and also essential for renewable energy storage systems. This review paper focuses on batteries and addresses concerns, difficulties, and solutions associated with them. It explores key technologies of Battery Management System, including battery modeling, state estimation, and battery charging. A thorough analysis of numerous battery models, including electric, thermal, and electro-thermal models, is provided in the article. Additionally, it surveys battery state estimations for a charge and health. Furthermore, the different battery charging approaches and optimization methods are discussed. The Battery Management System performs a wide range of tasks, including as monitoring voltage and current, estimating charge and discharge, equalizing and protecting the battery, managing temperature conditions, and managing battery data. It also looks at various cell balancing circuit types, current and voltage stressors, control reliability, power loss, efficiency, as well as their advantages and disadvantages. The paper also discusses research gaps in battery management systems.publishedVersio

Vertically integrated modules for low power embedded sensor systems

A typical embedded sensor system consists of an environmental sensor, data storage, and a control circuit (such as a microcontroller). Two main traits desired of these embedded sensor systems are small form factor and low power consumption. However, due to the diverse nature of the design and applications, monolithic solutions incorporating the three main components are often not available on a large cost effective scale. This work describes a method of integrating heterogeneous circuit components into a single module. When combined with efficient operating algorithms the system size is reduced and lifetime is extended. Production or custom designed component chips are thinned and stacked vertically while interconnects are fabricated within the module providing a 3-D integration (3DI) of the system. A Global Positioning System (GPS) location recording sensor system is designed with the intention of applying the 3DI process to reduce its size and power consumption

Design Space Evaluation for Resonant and Hard-charged Switched Capacitor Converters

USB Power Delivery enables a fixed ratio converter to operate over a wider range of output voltages by varying the input voltage. Of the DC/DC step-down converters powered from this type of USB, the hard-charged Switched Capacitor circuit is of interest to industry for its potential high power density. However implementation can be limited by circuit efficiency. In fully resonant mode, the efficiency can be improved while also enabling current regulation. This expands the possible applications into battery chargers and eliminates the need for a two-stage converter.In this work, the trade-off in power loss and area between the hard-charged and fully resonant switched capacitor circuit is explored using a technique that remains agnostic to inductor technology. The loss model for each converter is presented as well as discussion on the restrained design space due to parasitics in the passive components. The results are validated experimentally using GaN-based prototype converters and the respective design spaces are analyzed

하이브리드 전력 저장 시스템의 설계 및 운용 최적화

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2013. 2. 장래혁.전기 에너지 저장 (electrical energy storage, EES) 시스템은 필요에 따라 에너지를 저장하였다가 사용함으로써 에너지 효율과 안정성을 높이고 에너지 단가를 낮추는 등의 기능을 한다. EES 시스템은 비상용 전기 공급, 부하 평준화, 첨두부하 분산, 재생에너지 발전을 위한 에너지 저장 등의 다양한 분야에서 응용할 수 있다. 현재 EES 시스템은 주로 단일 종류의 에너지 저장 기술을 사용하고 있는데, 아직까지 그 어떤 에너지 저장 기술도 높은 에너지 및 전력 밀도, 낮은 가격, 높은 충방전 효율, 긴 수명 등 이상적인 에너지 저장 기술의 모든 요건을 충족시키고 있지 못하고 있다. 하이브리드 전력 저장 (hybrid electrical energy storage, HEES) 시스템은 여러 다른 종류의 에너지 저장 소자를 이용하여 각각의 장점을 활용하여 단점을 보완하는 기법으로, EES 시스템의 성능을 개선시시키기 위한 실용적인 접근 방법 가운데 하나이다. HEES 시스템은 정교한 시스템 설계와 제어기법을 통해 각각의 에너지 저장 소자의 장점을 모두 합친 것과 같은 성능을 갖출 수 있다. 본 학위 논문은 HEES 시스템의 에너지 효율을 최대화하기 위한 고수준의 최적화 기법들을 소개한다. HEES 시스템의 새로운 구조들과 체계적인 최적 설계 기법들을 제시한다. 제안된 네트워크 전하 전송망 (charge transfer interconnect, CTI) 구조와 뱅크 (bank) 재구성 구조는 전력 변환 손실을 최소화하여 HEES 시스템의 전하 전송 효율을 최대화한다. 또한 기존의 제어 기법들이 가진 한계점을 지적하고, 이를 보완하기 위해 전력원을 동시에 고려하여 설계하고 제어하는 기법을 제시한다. 제안된 최대 전력 전달 추종 (maximum power transfer tracking, MPTT) 기법과 이를 고려한 설계 기법은 실직적인 에너지 수집량을 증가시키고 실제적으로 사용 가능한 에너지량을 증가시킨다. 마지막으로 제안된 기법의 실현 가능성을 검증하기 위한 HEES 시스템 프로토타입 구현을 소개한다.Electrical energy storage (EES) systems provides various benefits of high energy efficiency, high reliability, low cost, and so on, by storing and retrieving energy on demand. The applications of the EES systems are wide, covering contingency service, load leveling, peak shaving, energy buffer for renewable power sources, and so on. Current EES systems mainly rely on a single type of energy storage technology, but no single type of EES element can fulfill all the desirable characteristics of an ideal electrical energy storage, such as high power/energy density, low cost, high cycle efficiency, and long cycle life. A hybrid electrical energy storage (HEES) system is composed of multiple, heterogeneous energy storage elements, aiming at exploiting the strengths of each energy storage element while hiding its weaknesses, which is a practical approach to improve the performance of EES systems. A HEES system may achieve the a combination of performance metrics that are superior to those for any of its individual energy storage elements with elaborated system design and control schemes. This dissertation proposes high-level optimization approaches for HEES systems in order to maximize their energy efficiency. We propose new architectures for the HEES systems and systematic design optimization methods. The proposed networked charge transfer interconnect (CTI) architecture and bank reconfiguration architecture minimizes the power conversion loss and thus maximizes the charge transfer efficiency of the HEES system. We also point out the limitation of the conventional control schemes and propose a joint optimization design and control considering the power sources. The proposed maximum power transfer tracking (MPTT) operation and MPTT-aware design method effectively increases energy harvesting efficiency and actual available energy. We finally introduce a prototype of a HEES system implementation that physically proves the feasibility of the proposed HEES system.1 Introduction 1.1 Motivations 1.2 Contribution and Significance 1.3 Organization of Dissertation 2 Background and Related Work 2.1 Electrical Energy Storage Elements 2.1.1 Performance Metrics 2.1.1.1 Power and Energy Density 2.1.1.2 Capital Cost 2.1.1.3 Cycle Efficiency 2.1.1.4 State-of-Health and Cycle Life 2.1.1.5 Self-Discharge Rate 2.1.1.6 Environmental Impacts 2.1.2 Energy Storage Elements 2.1.2.1 Lead-Acid Batteries 2.1.2.2 Lithium-Ion Batteries 2.1.2.3 Nickel-Metal Hydride Batteries 2.1.2.4 Supercapacitors 2.1.2.5 Other Energy Storage Elements 2.2 Homogeneous Electrical Energy Storage Systems 2.2.1 Energy Storage Systems 2.2.2 Applications of EES Systems 2.2.2.1 Grid Power Generation 2.2.2.2 Renewable Energy 2.2.3 Previous Homogeneous EES Systems 2.2.3.1 Battery EES Systems 2.2.3.2 Supercapacitor EES Systems 2.2.3.3 Other EES Systems 2.3 Hybrid Electrical Energy Storage Systems 2.3.1 Hybridization Architectures 2.3.2 Applications of HEES Systems 2.4 EES System Components Characteristics 2.4.1 Power Converter 2.4.2 Photovoltaic Cell 3 Hybrid Electrical Energy Storage Systems 3.1 Design Considerations of HEES Systems 3.2 HEES System Architecture 3.3 Charge Transfer and Charge Management 3.4 HEES System Components 3.4.1 Nodes 3.4.1.1 Energy Storage Banks 3.4.1.2 Power Sources and Load Devices 3.4.2 Charge Transfer Interconnect 3.4.3 System Control and Communication Network 4 System Level Design Optimization 4.1 Reconfigurable Storage Element Array 4.1.1 Cycle Efficiency and Capacity Utilization of EES Bank 4.1.2 General Bank Reconfiguration Architecture 4.1.3 Dynamic Reconfiguration Algorithm 4.1.3.1 Cycle Efficiency 4.1.3.2 Capacity Utilization 4.1.4 Cycle Efficiency and Capacity Utilization Improvement 4.2 Networked Charge Transfer Interconnect 4.2.1 Networked Charge Transfer Interconnect Architecture 4.2.1.1 Charge Transfer Conflicts 4.2.1.2 Networked CTI Architecture 4.2.2 Conventional Placement and Routing Problems 4.2.3 Placement and Routing Problems 4.2.4 Force-Directed Node Placement 4.2.5 Networked Charge Transfer Interconnect Routing 4.2.6 Energy Efficiency Improvement 4.2.6.1 Experimental Setup 4.2.6.2 Experimental Results 5 Joint Optimization with Power Sources 5.1 Maximum Power Transfer Tracking 5.1.1 Maximum Power Transfer Point 5.1.1.1 Sub-Optimality of Maximum Power Point Tracking 5.1.1.2 Maximum Power Transfer Tracking 5.1.2 MPTT-Aware Energy Harvesting System Design 5.1.2.1 Optimal System Design Problem 5.1.2.2 Design Optimization 5.1.2.3 Systematic Design Optimization 5.1.2.4 Energy Harvesting Improvement 5.2 Photovoltaic Emulation for MPTT 5.2.1 Model Parameter Extraction 5.2.2 Dual-Mode Power Regulator with Power Hybridization 5.2.2.1 PV Module I-V Characteristics 5.2.2.2 Modes of Operation 5.2.2.3 Circuit Design Principle 5.2.2.4 Dual-Mode Power Regulator Control 5.2.2.5 Implementation 5.2.2.6 Experiments 6 Experiments 6.1 HEV Application 6.1.1 Regenerative Brake 6.1.2 PV Modules 6.1.3 EES Bank Reconfiguration and Networked CTI 6.1.4 Overall Improvement and Cost Analysis 6.2 HEES Prototype Implementation 6.2.1 Design Specifications 6.2.1.1 Power Input and Output 6.2.1.2 Power and Energy Capacity 6.2.1.3 Voltage and Current Ratings 6.2.1.4 EES Elements 6.2.2 Implementation 6.2.2.1 Bank Module 6.2.2.2 Controller and Converter Module 6.2.2.3 Charge Transfer Interconnect Capacitor Module 6.2.2.4 Bidirectional Charger 6.2.2.5 Supervising Control Software 6.2.2.6 Component Assembly 6.2.3 Control Method 7 Conclusions and Future DirectionsDocto

Secondary aerospace batteries and battery materials: A bibliography, 1969 - 1974

This annotated bibliography on the subject of secondary aerospace battery materials and related physical and electrochemical processes was compiled from references to journal articles published between 1969 and 1974. A total of 332 citations are arranged in chronological order under journal titles. Indices by system and component, techniques and processes, and author are included

Using atmospheric pressure tendency to optimise battery charging in o-grid hybrid wind-diesel systems for telecoms

Off grid telecom base stations in developing nations are powered by diesel generators. They are typically oversized and run at a fraction of their rated load for most of their lifetime. Operating these generators at partial load is inefficient and over time physically damages the engine. A hybrid configuration,which is the combination of multiple energy sources, uses a battery bank which powers the telecoms load for a portion of the time. The generator only operates when the battery bank needs to be charged. Adding a wind turbine further reduces the generator run hours and saves fuel. The generator is oblivious to the current wind conditions which lead to simultaneous generator-wind power production. As the batteries become charged by the generator, the wind turbine controller is forced to dump surplus power as heat through a resistive load. This dissertation details how the relationship between barometric pressure and wind speed can be used to add an additional layer of sophistication to the battery charger. A numerical model of the system is developed to test the different battery charging configurations. This work demonstrates that if the battery charger is aware of upcoming wind conditions it will provide modest fuel savings and reduce generator run hours in small scale hybrid energy systems. The contribution from this work provides insight into the power being wasted in small scale hybrid systems with storage and how they can operate more efficiently when the charging mechanism is aware of upcoming wind conditions. The system will operate more efficiently if the diesel generator is disengaged during periods of moderate to high wind power production. The methodology proposed in this dissertation ensures that this is the case, especially during periods of high wind power production