Analisis Performansi Kualitas Daya Konverter Penyearah Untuk Aplikasi Charger Kendaraan Listrik

Penyerah (rectifier) merupakan suatu beban non linier yang mengakibatkan adanya distorsi harmonisa pada sistem tenaga. Pada penelitian ini, topologi rectifier yang dirancang merupakan topologi yang digunakan pada charging kendaran listrik yaitu three-phase buck type rectifier, Vienna rectifier, dan three-phase boost type rectifier. Masing-masing topologi memiliki performansi kualitas daya yang berbeda untuk itu dilakukanlah penelitian ini untuk melakukan simulasi pada operasi dari berbagai topologi rectifier untuk mendapatkan perbedaan dan perbandingan performansi kualitas daya dari beberapa topologi rectifier pada charger kendaraan listrik. Topologi ini akan disimulasikan dengan sumber yang sama dan beban yang sama. Beban pada masing-masing topologi akan divariasikan untuk mengetahui pengaruh besaran beban pada topologi rectifier. Penelitian ini dilakukan melalui simulasi pada software Simulink/MATLAB. Berdasarkan simulasi yang telah dilakukan, didapatkanlah persentase harmonisa terkecil terjadi pada topologi three-phase buck type rectifier. Untuk topologi dengan nilai persentase harmonisa terbesar yaitu topologi Vienna rectifier. Besarnya nilai beban pada topologi mempengaruhi nilai THD. Untuk operasi rectifier yang memiliki nilai power factor paling ideal adalah three-phase buck type rectifier dan nilai power factor yang paling tidak ideal adalah Vienna rectifier. Untuk itu dari simulasi yang telah di lakukan ini dapat dinyatakan yang memiliki performansi kualitas daya yang paling baik adalah topologi three-phase buck type rectifier

Detailed Thermal Characterization on a 48V Lithium-Ion Battery Pack during Charge-Discharge Cycles

This study experimentally investigates the temperature distribution and behavior of a 48V Lithium-Ion (Li-ion) battery pack during two charge-discharge cycles using 25 thermocouples. Results indicate that better convective heat transfer occurs at the external surfaces of the pack, while middle cells reach maximum temperatures. Differences are also observed in the behavior of the three modules. The discharge cycle shows a temperature rise of 5.8{\deg}C with a pack temperature gradient increasing from 1.3{\deg}C to 2.7{\deg}C. The study highlights the importance of assessing the thermal behavior of each module and the complexity of the Li-ion battery pack system. Findings on the battery cells, modules, and pack in the same study can provide valuable insights for designing efficient cooling systems for Li-ion battery packs.Comment: 11 pages, 4 figure

Computational assessment of the thermal response of a Li-ion battery module to transient loads

This paper provides a methodology to assess the average surface temperature of battery cells under realistic transient scenarios. Computational fluid dynamics modelling of battery cooling is conducted for the cases exposed to the ramps of internal heat generation inferred from the standard driving cycles. The results are then post-processed to determine the effectiveness of air and water as the coolant fluids. A quantitative measure of the maximum overshoot, dimensionless settling (DST), heating (DHT), and cooling (DCT) time is subsequently presented. It is shown that, compared to water, air produces a considerably delayed response to temporal changes in the internal heat generation and is slower at reaching the new steady state condition. Cooling battery cells by using water almost always ensures remaining within the safe operating range. Nonetheless, regardless of the coolant type, the long period ramps tend to produce smaller values of DST. The primary origin of the delay is the slow heat conduction within the battery cells. In addition, it is shown that water responds to changes in the internal heat generation far quicker during the heating and the cooling phases. The study highlights the importance of transient analyses for characterising the thermal behaviour of battery packs

Sistem Monitoring Performa Baterai dan Pengaturan Charging Baterai pada Keypoint PT. PLN UP2D Jawa Timur Berbasis Fuzzy Logic Controller

Baterai pada keypoint memiliki peran penting untuk menjaga keandalan sistem distribusi. Performa baterai yang baik, akan mendukung kinerja peralatan yang ditunjangnya. Energi yang dapat disimpan baterai jumlahnya terbatas, maka baterai akan mengalami siklus charge dan discharge. Proses charge dan discharge yang tidak tepat dapat menyebabkan performa baterai menurun. Apabila performa baterai sudah tidak dalam kondisi yang baik maka dapat menyebabkan keypoint gagal melaksanakan manuver ketika sumber daya utama mengalami gangguan. Oleh karena itu diperlukan suatu sistem yang dapat memantau performa baterai sebagai upaya preventif hal tersebut akan terjadi. Selain itu diperlukan juga suatu sistem yang dapat mengontrol charging baterai untuk menjaga performa baterai. Kontroler logika fuzzy akan diimplementasikan pada sistem kontrol charging baterai. Hasil simulasi menunjukkan proses charging pada keypoint sudah sesuai dengan menggunakan control current dengan arus konstan 4 A ketika SoC kurang dari 95% dan menggunakan control voltage dengan tegangan 26.12 V ketika SoC lebih dari 95%. Sistem monitoring menggunakan kapasitansi baterai dapat menunjukkan bagaimana kondisi kapasitas baterai dengan menghasilkan kapasitansi terbesar (peak) 1600 C saat 17 Ah dan menghasilkan peak 1400 C saat 15 Ah. ============================================================================================================================== Batteries on keypoints have an important role to maintain the reliability of the distribution system. Good battery performance, will support the performance of the equipment it supports. The amount of battery that can be stored is limited, the battery will pass a charge and discharge cycle. Inaccurate charge and discharge processes can cause battery performance to decrease. If the battery's performance is not in good condition, it can cause the keypoint to fail to perform a maneuver when the main resource is experiencing interference. Therefore we need a system that can monitor the performance of the battery as a preventive measure that will occur. In addition, a system that can control charging the battery is also needed to maintain battery performance. The fuzzy logic controller will be implemented on the battery charging control system. The simulation results show the charging process at the keypoint is appropriate using control current with a constant current of 4 A when the SoC is less than 95% and uses a control voltage with a voltage of 26.12 V when the SoC is more than 95%. The monitoring system using battery capacitance can show the condition of battery capacity by producing the largest capacitance (peak) of 1600 C when 18 Ah and producing a peak of 1400 C when 15 Ah

Power Distance Table for EV Charger Stations in Distribution System

In this thesis, the aim is to investigate the unbalanced voltage behaviour of the fast charging stations and their effects on distribution power systems. In the first stage, the fast charger is developed to derive the response of the charger to the unbalanced input voltage. This response allows us to model the charging station as a load in power flow analysis. In the next stage of the study, a simplified model is proposed to incorporate the behaviour of the fast charger in power flow analysis. Different feeders data of IEEE benchmarks such as IEEE 34-bus, 37-bus, and 123-bus are used in the base benchmark, which is IEEE 30-bus, using the proposed simplified model. Then, maximum charging capacity of the stations and unbalanced voltage ratio (UVR) is calculated for any bus of interest that the charging station has been connected to. This task is done while the system is exposed to two constraints of UVR and voltage. The power flow analysis results indicate that for the different feeders data, UVR of the system after connection of charging stations is the dominant constraint for some buses and it prevents further integration of fast charging station to the distribution system. Therefore, in order to mitigate unbalanced voltage in the system, partial transposition is utilized. In the partial transposition, the feeders are transposed and divided in two equal sections. After applying partial transposition to the feeders data, for the case of IEEE 34-bus, the UVR after connection of charging station was below the permissible value of 3%, but for IEEE 37-bus and 123-bus some buses still suffer from high UVR. Accordingly, a modified partial transposition was adopted as another alternative. The results demonstrate that the UVR of the system after applying modified partial transposition to the feeder data of IEEE 37-bus and 123-bus has decreased below the standard value of 3% and the system can accommodate higher capacity of fast charging stations. Finally, according to the power flow analysis a power distance table is acquired for the feeders data that predicts the maximum charging capacity that can be connected to the system based on its distance from the main source without violating the systems operational constraint

Estimasi State of Charge (SOC) pada Baterai Lead-Acid dengan Menggunakan Metode Coulomb Counting pada PV Hybrid

Baterai merupakan komponen yang penting dalam implementasi renewable energy. Salah satu jenis baterai yang sering digunakan dalam implementasi renewable energy adalah baterai Lead-Acid. Estimasi nilai SOC (state of charge) yang akurat menjadi salah satu parameter yang penting dalam perancangan BMS (Battery Management System). Estimasi nilai SOC yang akurat sangat diperlukan untuk menghindari baterai beroperasi dalam keadaan over charge dan over dischrage. Salah satu metode estimasi SOC yang cukup mudah dan sering digunakan adalah Coulomb Counting. Penentuan estimasi SOC dengan metode ini dilakukan dengan menjumlahkan muatan yang masuk atau muatan yang keluar dari baterai dalam kurun waktu tertentu. Penjumlahan muatan dapat dilakukan dengan melakukan penjumlahan perkalian arus dan waktu pada baterai, baik pada saat pengisian dan pengosongan. Pada tugas akhir ini dirancang sebuah alat monitoring SOC dengan menggunakan metode coulomb counting untuk melakukan monitoring nilai SOC baterai baik pada saat pengisian dan pengosongan. Pada implementasinya metode ini sangat bergantung pada nilai initial SOC yang akurat serta keakuratan sensor arus yang digunakan. Jenis sensor arus yang digunakan dalam alat monitoring SOC ini adalah ACS712 yang memiliki keakuratan yang baik. Berdasarkan hasil pengujian yang dilakukan, jumlah muatan pada baterai berbanding lurus dengan SOC pada baterai itu sendiri. =============== Battery is an important component in the implementation of renewable energy. One type of battery that is common used in the implementation of renewable energy is the Lead-Acid battery. Accurate estimation of SOC (state of charge) values becomes one of the important parameters in the design of BMS (Battery Management System). Establishing accurate SOC value estimates is necessary to avoid batteries operating in over charge and over discharges. One method of SOC estimation is easy and common used is “coulomb counting”. Determination of SOC estimation with this method by summing the coulomb that in or come out of the battery with a certain period of time. The sum of the coulomb can be calculate by adding the current to the battery, either during charging and discharging. In this final project will designed a SOC monitoring tool using coulomb counting method to monitor the value of SOC battery both at charging and discharging with a certain period of time. In the implementation of this method is very dependent on the accurate initial SOC value and accuracy of current sensors used. The type of current sensor used in this SOC monitoring tool is ACS712 which has good accuracy. Based on the results of the tests performed, the amount of coulomb on the battery is proportional to the SOC battery value

Sistema de gestão de estudos e ensaios aplicado a baterias da rede elétrica de distribuição

A EDP Distribuição, como Operador da Rede Elétrica de Distribuição Portuguesa, necessita garantir a continuidade do fornecimento energético. As Subestações AT/MT, como um dos principais elementos na Rede Elétrica de Distribuição, incorporam sistemas que asseguram a proteção, o comando e o controlo dos seus equipamentos. A funcionalidade ininterrupta destes sistemas é suportada por Sistemas de Alimentação de Corrente Contínua que integram grupos de baterias. Em situação de falha da rede elétrica, o fornecimento de energia ao Sistema de Alimentação é interrompido, sendo o fornecimento de potência aos Sistemas de Serviços Auxiliares garantido sem qualquer interrupção pelo grupo de baterias. O índice de estimação do estado de saúde de baterias é um dos indicadores quantitativos condicente com o desempenho destas. A EDP Distribuição garante o correto desempenho, quando necessário, de todos os seus grupos de baterias, através da sua manutenção com ensaios de autonomia periódicos e sistemáticos. A posterior análise quantitativa do resultado obtido nos ensaios é efetuada segundo um algoritmo de estimação do estado de saúde global do grupo de baterias. Esta dissertação apresenta o estudo da metodologia de ensaios da EDP Distribuição, bem como da algoritmia adotada na estimação do estado de saúde de baterias. Como projeto prático, propostas de melhoria da algoritmia são estruturadas e descritas neste documento. De modo a diminuir a componente manual na execução de processos de arquivo, estudos e algorítmicos, a dissertação comtempla a estruturação, implementação e validação do desenvolvimento de um software de automatização de processos.The Portuguese Electric Power System Operator (EDP Distribuição) needs to ensure a continuous energy supply. As one of the most important elements in the Electric Power System, the HV/MV Substations have built-in systems that protect, command and control their equipment. The uninterrupted functionality of these systems is supported by Direct Current Power Systems that integrate battery packs. In the event of a power failure, the energy supply to the Direct Current Power System is interrupted, whereas power supply to the Auxiliary Services Systems is guaranteed, without interruption, by the battery pack. The Health Condition estimation index is one of the quantitative indicators for the battery performance assessment. EDP Distribuição guarantees the correct performance, when needed, of all its battery groups, by maintaining these with periodic and systematic autonomy tests. The subsequent quantitative analysis of the tests result is carried out according to an algorithm to estimate the overall health condition of the battery pack. This dissertation presents the study of the test methodology implemented by EDP Distribuição, as well as the algorithm adopted in the estimation of the health condition of batteries. As a practical project, algorithm-improvement proposals are structured and described in this document. In order to reduce the manual component in the execution of archival, study and algorithmic processes, this dissertation contemplates the structuring, implementation and validation of the development of a process automation software

Metodología de diseño para instalaciones solares residenciales en la ciudad de Medellín

Debido a su gran recurso hídrico, la principal fuente de generación de energía eléctrica en Colombia proviene de centrales hidroeléctricas, cerca del 70% al 80 % (según variaciones en la hidrología) de la composición de la matriz energética se deriva de este recurso. Sin embargo, esta dependencia pone el riesgo al país debido a lo impredecible que es la naturaleza, reflejado en los periodos de escasez originados por fenómenos como el niño y que han ocasionado que el precio de la energía eléctrica en bolsa tenga una tendencia al alza. Una forma de mitigar los impactos generados por esta vulnerabilidad es con el uso de energías alternativas aprovechando la zona ecuatorial en la que se ubica Colombia, este potencial energético se ha explorado a nivel de las zonas no interconectadas principalmente, pero si se toma el sector residencial como objeto de estudio, se estaría evaluando un sector que tiene un alto porcentaje de demanda del consumo total de energía, pero que entre otros factores como la ineficiencia en las políticas de promoción e incentivos para la autogeneración y otras causas asociadas al desconocimiento técnico de esta tecnología para el usuario común ha dificultado la penetración de estas en el mercado. Bajo este escenario, se presenta la siguiente investigación que tendrá como finalidad establecer una metodología de diseño para instalaciones solares residenciales considerando diferentes esquemas posibles de conexión mediante el uso de herramientas de búsqueda u optimización. Se buscará con esto evaluar y minimizar métricas financieras asociadas a este tipo de proyectos ubicados en el sector residencial de la ciudad de Medellín.Abstract: Due to the great water resource, the main source of electric power generation in Colombia the power of hydroelectric power plants, about 70% to 80% (according to variations in hydrology) of the energy composition of the matrix derives from this resource. However, this dependence puts the risk to the country due to the unpredictable nature, reflected in the periods of scarcity caused by phenomena such as the child and that have caused the price of electric power in the bag has a tendency to rise. One way to mitigate the impacts generated by this vulnerability is with the use of alternative energies taking advantage of the equatorial zone in which Colombia is located, this energy potential is explored a level of areas not interconnected mainly, but if the residential sector is taken As an object of study, there is a sector that has a high percentage of total energy consumption demand, but other factors such as inefficiency in promotion policies and incentives for self-generation and other causes associated with the technical unknown of this Technology For the user has made it difficult for them to penetrate the market. Under this scenario, the following research is presented that aims to establish a design methodology for residential solar installations considering different possible connection schemes through the use of search or optimization tools. The objective is to minimize the financial associated with this type of projects located in the residential sector of the city of Medellin.Maestrí

Multilevel Converters for Battery Energy Storage: How Many Levels and Why?

This work explores the potential benefits of cascaded H-bridge multilevel converters in low-voltage applications, particularly grid-attached battery energy storage systems (BESS). While some benefits of these are discussed in literature, this work seeks to create practical, quantitative models for system performance in terms of a number of key performance parameters. These models are then used to find the trends in these performance parameters with an increasingly high order converter, starting to answer the question of how many levels are best. The system performance parameters modelled are power loss, thermal performance and reliability. Wherever practical models and assumptions are validated, be that experimentally or through comparison with existing methods – this work includes a number of experimental series. The resulting trends explored highlight a number of interesting trends, principally: total power loss can be much lower, particularly at high switching frequencies; system thermal performance can be much improved owing to more efficient heatsink utilisation; and due to these thermal benefits, the system reliability based on switching device failure does not suffer as one might expect, and can in fact be higher under some conditions. The investigation also considers the use of cutting-edge switching device technology, such as gallium nitride power transistors, which a multilevel converter enables the use of, and in turn can significantly reduce power dissipation and increase switching frequency. Overall, the work adds new arguments in favour of multilevel converters in such applications and lowers the barrier to practical implementation by answering a number of questions a designer would likely ask. The key novel contributions of this work are the results of the trends that were found in terms of converter power loss, system thermal performance and switching device reliability with respect to multilevel converter order – with the methodologies created for these being somewhat novel in their own right. Along the way, however, other novel work was conducted including: an experimental investigation in to the accuracy of voltage-capacitance curves provided by manufacturers; experimental derivation of relationships for predicting MOSFET body diode performance from readily available device parameters; analysis showing the potential impact of GaN devices on converter efficiency; an experimental validation of GaN device gate turn-on energy; creation and validation of empirical relationship for predicting how heatsink performance varies with more devices of a smaller size; as well as an exploration of whether the extreme small size of some modern power transistors could lead to unexpected thermal cycling issues