Now showing 1 - 5 of 5
  • Publication
    Battery energy storage system assessment in a designed battery controller for load leveling and peak shaving applications
    This paper presents an assessment of three types of battery in a designed battery controller for a battery energy storage system (BESS) integrated with a solar photovoltaic system for load leveling and peak shaving applications. Three types of battery - lead acid, lithium ion, and nickel metal hydride - are discussed in detail and assessed in this work, focusing on small-scale integration. The controller was designed using Matlab Simulink to monitor consumer load demand, control the charging and discharging process of the BESS, and regulate while fulfilling the load demand, in addition to prolonging the BESS lifetime. From the simulation results, the nickel metal hydride battery is the best option for development of a battery controller. It achieved an average 37.45% leveled load profile and a 35.75% reduction of the load peak. However, the lead acid battery is still the dominant choice among consumers, in spite of average performance, because it has the best cost performance.
  • Publication
    MPPT charge controller using fuzzy logic for battery integrated with solar photovoltaic system
    In comparison to other Renewable Energy (RE) resources, solar energy has become the most prominent and prospective source for generating electricity, substituting conventional sources. However, solar Photovoltaic (PV) energy production is dependent on solar irradiance and cell temperature. By implementing the Maximum Power Point Tracking (MPPT) algorithm, it is achievable to maximize the power from solar PV. In spite of this, there is still a slower convergence rate, a significant fluctuation around Maximum Power Point (MPP), and a drift issue caused by rapid irradiance variations in solar PV. In order to prevent oscillation and attain a steady state and continuous output of the PV module, a Fuzzy Logic (FL)-based MPPT has been designed in this work. With the buck converter as the DC-DC converter and the lead acid battery as the input, the Perturb & Observe (P&O) MPPT method is selected. The overall design will be developed using Matlab Simulink, and the efficiency of the FL-MPPT charge controller will be evaluated under constant and step irradiance. Additionally, the battery's State of Charge (SOC) will be monitored to prevent overcharging and discharge. In addition, the effectiveness of the controller will be evaluated with and without the MPPT method. On the basis of simulation results obtained from constant and step irradiance levels, the FL-MPPT charge controller with the P&O algorithm and the lead acid battery as the load was able to maintain maximum system efficiency while extending battery life. The FL-MPPT charge controller obtained about 96% efficiency for both irradiance profiles, whereas the system without the FL-MPPT algorithm only achieved 42% efficiency.
  • Publication
    Design and performance analysis of fuzzy logic controller for solar photovoltaic system
    This study presents a Fuzzy Logic Controller (FLC)-based Maximum Power Point Tracking (MPPT) system for solar Photovoltaic (PV) setups, integrating PV panels, a boost converter, and battery storage. While FLC is known for its robustness in PV systems, challenges in battery charging and discharging efficiency can affect performance. The research addresses these challenges by optimizing battery charging, preventing overcharging, and enhancing overall system efficiency. The FLC MPPT system is designed to regulate the battery's State of Charge (SOC) while evaluating system performance under varying solar irradiance and temperature conditions. The system is modeled and simulated using MATLAB/Simulink, incorporating the PV system, MPPT algorithm, and models for the PV module and boost converter. System efficiency is assessed under different scenarios, with results showing 97.92% efficiency under Standard Test Conditions (STC) at 1000 W/m² and 25°C. Additionally, mean efficiencies of 97.13% and 96.13% are observed under varying irradiance and temperature, demonstrating the effectiveness of the FLC MPPT in regulating output. The system also extends battery life by optimizing power transfer between the PV module, boost converter, and battery, ensuring regulated SOC.
  • Publication
    Impedimetric cardiac biomarker determination in serum mediated by epoxy and hydroxyl of reduced graphene oxide on gold array microelectrodes
    A label-free chemical bonding strategy mediated by reduced graphene oxide (rGO) basal plane functional groups has been developed for cardiac Troponin I (cTnI) detection. Four different chemical strategies on respective electrode sensing surface were precedingly examined using electrochemical impedance spectroscopy. The impedimetric assessment was carried out by sweeping frequency at the range 0.1–500 kHz perturbated at a small amplitude of AC voltage (25 mV). The chemical strategy-4 denoted as S-4 shows a significant analytical performance on cTnI detection in spiked buffer and human serum, whereby the pre-mixture of rGO and (3-Aminopropyl)triethoxysilane (APTES) creates a large number of amine sites (−NH2), which significantly enhanced the antibody immobilization without excessive functionalization. The as-fabricated immunosensor exhibited an ultra-low limit of detection of 6.3 ag mL−1 and the lowest antigen concentration measured was at 10 ag mL−1. The immunosensor showed a linear and wide range of cTnI detection (10 ag mL−1–100 ng mL−1) in human serum with a regression coefficient of 0.9716, rapid detection (5 min of binding time), and stable and highly reproducible bioelectrode response with RSD < 5%. Hence, the demonstrated S-4 strategy is highly recommended for other downstream biosensors applications. Graphical abstract: [Figure not available: see fulltext.].
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  • Publication
    Impedimetric-based biosensor for Cardiac Troponin 1 detection: sensing strategy aided by Hybrid rGO and Gold Interdigitated Electrode
    (Universiti Malaysia Perlis (UniMAP), 2021)
    Cardiovascular diseases (CVD) are the number one cause of death among the noncommunicable diseases globally. CVD are referred to diseases that associated with the abnormalities of blood flow in heart and often related with ‘heart attack’ condition or in clinical term as an acute myocardial infarction (AMI). Cardiac Troponin I (cTnI) biomarker is widely accepted as gold standard for AMI recognition due to its high specificity. Hence, the need for portable and highly sensitive sensor with fast detection is utmost required to diagnose AMI for fast treatments. Herein, a label-free impedimetric-based cTnI immunosensors were fabricated and their analytical performances were assessed and reported in this thesis. Reduced graphene oxide (rGO) and gold interdigitated electrode (Au-IDE) were employed to develop the immunosensors. The research work is divided into two main sections; first is to obtain a uniform deposition of rGO through single-droplet drop-casting technique and second is to fabricate the cTnI immunosensor aided by rGO. The deposition results revealed the method-3 involving post-sonication technique produces a large and self-assembled of rGO nanoflakes through single-droplet drop-casting without the use of any chemical solvent. Furthermore, the rGO modified Au-IDE devices show an excellent electron mobility, whereby the electrical conductivity was enhanced approximately ~1000-fold compared to the bare devices. Thus, the as-prepared rGO suspension was used to fabricate the immunosensors. Four different surface modification strategies on respective bioelectrodes mediated by the as-prepared rGO suspension were investigated. Electrochemical impedance spectroscopy (EIS) was performed to characterize the immunosensors by sweeping frequencies from 0.1 - 500 kHz at a small AC voltage (25 mV). Results revealed that one of the four immunosensors developed through strategy-4 shows an excellent analytical performance for the cTnI antigen detection in spiked buffer and human serum. A potential surface functionalization mediated by rGO basal plane functional groups was postulated based on XPS and FTIR analyses. The as-fabricated immunosensor showed a wide linear range (10 ag/mL – 100 ng/mL) of cTnI antigen detection in human serum with a linear regression coefficient (R2) of 0.9716 and the lowest analytes detected was 10 ag/mL, whereby it shows highly selective and sensitive trait. The immunosensor also showed a fast-detection that only required 5 minutes for probe and targets binding and stable for nine days. The bioelectrodes were highly reproducible. Hence, such an electrode sensing surface modifications strategy can be further extrapolated for later applications in various biomarker mediated disease diagnoses.
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