Change In Output Voltage Research Articles

Effect of filter material and porosity on the energy storage capacity characteristics of diesel particulate filter thermoelectric conversion mobile energy storage system

The thermal energy generated by the diesel particulate filter (DPF) is converted into electrical energy through the thermoelectric generator (TEG) and stored in a mobile battery power energy storage (MBPE) system. The filter material and porosity directly affect the regeneration temperature of the DPF, which in turn affects the thermoelectric conversion capability of the thermoelectric module (TEM). This study explores the energy storage capacity characteristics for the DPF-TEG of the MBPES system at a regeneration temperature of 923 K. The filter materials considered are cordierite, mullite and SiC with porosities of 0.4, 0.45, 0.5, 0.55, 0.6, 0.65 and 0.7. The maximum output power and thermoelectric conversion efficiency are analyzed. The thermal input power for the SiC filter is approximately 2.4 times and 1.8 times than that of the cordierite filter and the mullite filter. As the porosity increases from 0.4 to 0.7, the output current for the DPF-TEG of the MBPES system with the 3 filter materials ranges from 0.66 A to 2.11 A. The output voltage changes from 50.62 V to 161.98 V. The maximum output power varies from 33.36 W to 341.59 W and the conversion efficiency rises from 0.88% to 2.72%.

DESIGN OF CLOSED LOOP MULTIPORT DC DC CONVERTER

In recent years, there has been lots of emphasis put on the development of renewable energy. While considerable improvement on renewable energy has been made, there are some inherent limitations for these renewable energies The Closed-Loop Multiport DC-DC Converter with Adaptive Sliding Mode Control (ASMC) is difficult in power electronics system designed to efficiently manage and control energy flow between multiple energy sources and loads in various applications, including renewable energy integration, electric vehicles, and microgrids. This paper provides an overview of the key features and benefits of this innovative converter system. Multiport DC-DC converters have gained significant attention due to their ability to interface multiple energy sources, such as solar panels and batteries with different voltage levels and power ratings, providing a versatile platform for energy management. The ASMC controller enhances the converter's performance by dynamically adjusting the control parameters based on system conditions and load requirements, thereby improving efficiency and reliability .The ASMC employs a sliding mode control strategy, a robust and adaptable control method, which ensures that the converter operates effectively under various operating conditions, including rapid changes in load and source characteristics. This control technique offers inherent advantages, such as fast transient response and reduced sensitivity to parameter variations, contributing to superior system performance. The ASMC controller optimizes power conversion by minimizing switching losses and ensuring that the converter operates close to its peak efficiency. The controller continuously adapts to changes in input voltage, output voltage, and load conditions, ensuring stable and reliable operation even in dynamic environments. The sliding mode control strategy enables rapid response to sudden load changes, making it suitable for applications with varying power demands. Key Words: DC-DC converter, Sliding-mode control, Battery, Solar PV.

Effect of fuzzy logic controller on voltage stability of parallel boost converter configuration

An increase in electricity load causes a change in grid voltage and current, causing losses to customers. In addition, the source of electricity from fossil energy has also decreased. Therefore this study aims to provide a stable DC voltage source from solar panels, with a Fuzzy Logic Controller (FLC). The proposed method is to design a boost converter in parallel with its output. The boost converter is used to increase the DC voltage from 24 V to 48 V. In this study, FLC is used to adjust the output voltage of each boost converter. This is so that if one of the boost converters fluctuates, the other boost converters will supply a voltage according to the load voltage. The results showed that the FLC can adjust the boost converter output voltage changes. Whereas when using the PI (Integral Proportional) controller, a voltage spike occurs in the range of 0 seconds to 0.6 seconds and the voltage stabilizes within 0.6 seconds to 1 second.

ДОСЛІДЖЕННЯ ХАРАКТЕРИСТИК ВИСОКОВОЛЬТНОГО БЕЗТРАНСФОРМАТОРНОГО РЕЗОНАНСНОГО ЗАРЯДНОГО ПРИСТРОЮ ЄМНІСНОГО НАКОПИЧУВАЧА

Electromagnetic processes in a high-voltage transformerless resonant device for charging capacitor are analyzed. The dependences of the output voltage and charging current on the relative load and the quality factor of the resonant circuit are obtained. The nature of the change in output voltage depending on the quality factor and relative load ratio is analyzed. Simulation of the researched converter operation is carried out. References 11, figures 6.

Dual-atom Co-Fe catalysts for oxygen reduction reaction

Controlled synthesis of dual-atom catalysts (DACs) for heterogeneous catalytic reactions is vital but still demanding. Herein, we construct a novel dual-atom catalyst containing FeN3-CoN3 sites on N-doped graphene nanosheets (CoFe-NG), which exhibits remarkable catalytic performance with a half-wave potential of 0.952 V for oxygen reduction reaction (ORR) and shows higher endurance to methanol/carbon monoxide poisoning and better durability than commercial Pt/C. The assembled Zn-air battery with CoFe-NG as the air electrode delivers a peak power density of 230 mW cm–2 and exhibits negligible change in output voltage at 5 mA cm–2 for 250 h. Theoretical calculations reveal that FeN3-CoN3 sites on N-doped graphene exhibit lower ORR barrier than FeN4 and CoN4 sites, and the rate-limiting step on the former is the transformation of *OH intermediate to H2O, different from the transformation of *O to *OH on the FeN4 site and the transformation of O2 to *OOH on the CoN4 site.

A Robust Duty‐Cycle‐Comparison‐Based Overload Detector for DC‐DC Converter

A novel duty‐cycle‐sensing overload detector for DC‐DC converter is proposed in this paper. Firstly, the theoretical analysis is conducted to reveal the susceptibility of the conventional overload detectors to temperature variation and the input/output‐voltage change of the DC‐DC converter. Then, the schematic of the novel duty‐cycle‐sensing overload detector is presented and its operation principle is analyzed. Thanks to the time register, the proposed detector generates a theoretically voltage‐and‐temperature‐insensitive threshold duty cycle, compares it with the real‐time duty cycle of the converter's PWM signal, and announces an overload event if the real‐time duty cycle exceeds the threshold. Finally, a prototype of a BUCK DC‐DC converter including the proposed detector and a conventional current‐sensing overload detector is constructed and measured. As the measurement results show, the threshold duty cycle only varies by about 2.4% as the temperature changes from 0 to 90 °C while the threshold voltage of the conventional current‐sensing detector changes by about 4.6%. The proposed detector can keep effective even the temperature rises to 90 °C while the conventional current‐sensing detector can work at a temperature no higher than 85 °C. Without circuitry modification, the proposed detector correctly senses the overload event as the DC‐DC converter's output voltage changes in a range of 2.1–2.9 V while the conventional one loses its effectiveness if the output voltage is set higher than 2.54 V. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Design and Experimental Validation of a Noninvasive Glucose Monitoring System Using RF Antenna-Based Biosensor

This article presents an end-to-end microwave-based system to detect the glucose level in aqueous solutions through a noninvasive scheme. A microwave signal is generated and transmitted through the sample under test (i.e., glucose–water solution). The received signal is then conditioned using a low-noise amplifier (LNA), a bandpass filter (BPF), and an RF detector. The change in the dc output voltage on the receiver side is used as a new way to detect the glucose level. The proposed glucose sensor is implemented using two RF microstrip patch antennas that resonate at 5.7 GHz and are fabricated using an FR-4 substrate. The design specifications of the sensing antennas are thoroughly studied and presented. The system is verified experimentally using glucose–water testing samples. The experimental results confirm the correlation between the glucose concentration and the dc output voltage for a concentration range of 0–5000 mg/dL. The effect of the transmitted power level on the system performance is also investigated. Finally, the proposed system is compared with the state-of-the-art systems reported in the literature.

Tunnel Magnetoresistance-Based Sensor for Biomedical Application: Proof-of-Concept

The aim of this work was to investigate and prove the possibility of the real-time detection of magnetic nanoparticles (MNPs) distributed in solid material by using a tunnel magnetoresistance-based (TMR) sensor. Following the detection tests of FeCrNbB magnetic nanoparticles distributed in transparent epoxy resin (EPON 812) and measuring the sensor output voltage changes at different particle concentrations, the detection ability of the sensor was demonstrated. For the proposed TMR sensor, we measured a maximum magnetoresistance ratio of about 53% and a sensitivity of 1.24%/Oe. This type of sensor could facilitate a new path of research in the field of magnetic hyperthermia by locating cancer cells.

A Laminated Continuum Robot With Gripping Force-Sensing Forceps for Robot-Assisted Minimally Invasive Surgeries

Minimally invasive surgeries (MISs) or natural orifice transluminal endoscopic surgeries (NOTESs), such as the transurethral resection of bladder tumor (TURBT), require the surgical robot to be miniaturized to perform surgical procedures in narrow spaces. However, miniaturization of surgical robots poses problems in its fabrication and sensor integration. In this article, a miniature continuum surgical robot is proposed with force-sensing surgical forceps, which can be fabricated through a 2-D lamination process and converted into 3-D through folding. This multimaterial laminated structure facilitates the integration of photoelectric sensors into the surgical forceps. Then, the gripping force of the surgical forceps is sensed from the change of the output voltage of the integrated photoelectric sensor. The sensitivity of gripping force to the change of output voltage is 3.6 N/V, and the maximum error during calibration is 0.03 N. The proposed robot and the gripping force sensing method are validated through simulations and experiments, such as gripping and releasing objects of various hardness and heights. It is also validated that the gripping force information could also improve the gripping performance in the object handling experiment and ex vivo porcine intestine gripping experiment.

Fault Detection Methods Suitable for Automotive Applications in Proton Exchange Fuel Cells

The fault conditions degrade the performance of proton exchange fuel cells and reduce their useful life. The prolonged existence of a fault condition can permanently damage the fuel cell. This paper proposes four methods for fault detection and fault type isolation. These methods were based on the coefficient of variance, ratios of change in output power to change in voltage and change in output voltage to the change in current, fuzzy membership values and Euclidian distance, and wavelet transform. These methods are non-invasive to the fuel cell and involve non-destructive testing. These methods were experimentally validated.

Calcium Titanate Orthorhombic Perovskite-Nickel Oxide Solar-Blind UVC Photodetectors with Unprecedented Long-Term Stability Exceeding 500 Days and Their Applications to Real-Time Flame Detection

In recent years, the rapid increase in fire frequency has led to demands for efficient fire monitoring systems. To realize sensitive and large-area fire monitoring, flame sensing based on an ultraviolet C (UVC) photodetector can be considered as a promising approach. However, the challenges such as the high-cost process, limited selection of photoactive materials with an appropriate band gap, inefficient power consumption, stability issues, and environmental noise interference restrict the development of UVC photodetectors (PDs) for practical flame safeguard applications. Here, we demonstrate flame detection with a UVC PD based on an ultrawide band gap calcium titanate (CTO) and nickel oxide (NiO) heterostructure. The proposed PD achieves a high solar-blinded rejection ratio (at UVC light/UVA light) of 2.9 × 104, on/off switching current ratio of 120 A/A under UVC light and dark state, robust and stable operation longer than 1 year (502 days), and specific detectivity as high as 4.44 × 1011 Jones under zero-voltage bias operation. During the flame combustion, the CTO/NiO UVC PD exhibits a systematic real-time output voltage change with flame intensity variation, which opens up new possibilities for rapid and accurate fire detection.

A Maximum Power Point Tracker Using the Bald Eagle Search Technique for Grid-Connected Photovoltaic Systems

Maximum power point tracker (MPPT) methods work to maximize the output power of a PV system under changes in meteorological conditions. The performance of these methods depends on the complexity of the algorithm and the number of used variable inputs for obtaining the MPP value. Moreover, they oscillate around the MPP in steady-state operations, causing a waste of power and power loss. Moreover, they do not work perfectly for a PV system running under partial shading conditions. Therefore, this paper proposes modifications to the global maximum power point bald eagle search-based (GMPP BES) method so that it runs as an MPPT as well. The modifications enable the GMPP BES method to detect minor changes in insolation and temperature by observing the changes in the PV array output voltage and, accordingly, trigger the search for the suitable MPP voltage. An experimental setup using a real-time digital simulator (RTDS) was utilized to evaluate the modified GMPP BES-based method under real changes in insolation and ambient temperature. The RTDS simulations confirm the capability of the modified method to accurately and efficiently locate the MPP values. Furthermore, the results demonstrate that the proposed method performs better than the perturb and observe (PO) method concerning its ability to respond to changes in insolation and ambient temperature and its ability to arrive at correct MPP values with nearly zero oscillation around the maximum power point. Thus, with these advantages, the proposed method can be considered a practical solution for solar farms that have to harvest large amounts of energy.

입력전압 및 구동주파수 변화에 따른 직렬-직렬 보상 무선전력전송회로의 성능 분석

In series-series compensated wireless power transfer, input voltage control and operating frequency control methods are used to improve the problem of output voltage change according to load variation. However, if two methods are used to maintain the output voltage, the efficiency of the circuit and the power loss of each element change. Therefore, in this paper, the characteristics, advantages and disadvantages of these methods are compared and analyzed through simulation. For this, the coil and circuit parameters are calculated using COMSOL simulator and design equations to model the circuit, and the performance of the two methods is compared and analyzed with PSIM simulator. In the simulation, when the load changes from 4.5Ω to 9Ω at an output power of 9W to 18W, the output voltage is maintained at 9V by using the input voltage or frequency control methods. As a result of the simulation, the input voltage control method produces an output voltage of 9V in the entire load range by increasing the input voltage even if the voltage gain is not sufficient, and has the maximum efficiency of 86.55% at a load of 4.5Ω. On the other hand, the frequency control method can not produce an output voltage of 9V because the voltage gain is small at a low load, and the circuit efficiency decreases due to an increase in the reactive current at a high load.

Respirometry Rate Measurement by Pyroelectric Effect of a Piezo Sounder—Monitor and Alarm by Single Device

This article describes a novel application of a piezoelectric sounder on an acoustic device as a respiratory detector. When human exhaled air at a temperature of 36.5 °C is blown onto the piezoelectric device in the sounder in a room of 26.4 °C, a peak voltage of 1–2 V directly appears without an amplifier. We herein present a theoretical model of how the device works, experimentally prove its validity, and show its potential to be used as a spirometry detector. The output voltage changes alongside the output of a medical spirometer for forced vital capacity test respiration. The device is noise robust under a variety of measurement conditions, including different masks, shields, snorkels, and sustained airway positive pressure devices. The S/N ratios for quiet sitting, walking, quick face swing, and mask movement were 38, 33.3, 32.3, and 30.9 dB, respectively. The piezoelectric sounder considered herein can return to the original function and generate an alarm if the measured reparation is abnormal.

DC fault current-limiting method based on dual-loop active control for modular multilevel converters

PurposeIn the event of a DC short-circuit fault in a flexible DC power grid, the high peak value of the fault current puts forward more stringent requirements on the DC circuit breaker. The existing fault current cutoff mainly focuses on changing the topology structure. To suppress the development of fault current and reduce the investment cost of the DC grid, this paper aims to propose a dual-loop active current-limiting control based on energy difference.Design/methodology/approachFirstly, the equivalent circuit at fault is established, and the parameters related to the fault current are analyzed. Then, the relationship between the output voltage change of the bridge arm and the difference between the AC and DC energy is deduced. Finally, the experimental results are discussed on the real-time simulation platform Opal-RT.FindingsThe proposed current-limiting measures can greatly reduce the fault current, reduce the breaking current of the circuit breaker and increase the capacitor voltage during the fault period, which is beneficial to the stability of the AC system. It is verified that the proposed method is also applicable to a certain high-resistance fault.Originality/valueThis paper applies the method of AC fault to DC fault and deduces the relationship between energy difference and voltage variation corresponding to different step lengths based on digital simulation. In addition, two variables are used as control structure parameters to reduce the probability of system misoperation.

Concentric-Coil Hybrid IPT System With Improved Tolerance to Coupling and Load Variations

Hybrid tuning topologies had been proposed with polarized magnetic couplers to improve the alignment tolerance of inductive power transfer (IPT) systems. However, the technologies are mainly applicable to IPT systems with directional coupling and relatively low inductance variations. This article proposes an IPT system with a dual-concentric-coil transmitting (Tx) and single-coil receiving (Rx) coupling configuration with hybrid tuning networks for improving the output voltage characteristics over a wide range of coupling and load variations. The concentric coils allow free rotation while integrated hybrid tuning networks help reduce the output voltage fluctuation under varying horizontal and spatial misalignments. A design procedure is proposed using finite-element method (FEM) and circuit simulations to select tuning parameters accounting for varying self and mutual inductances. Simulation and experimental results show that the self-inductance of the proposed coil can change by 48%, and the coupling coefficient varies between 0.43 and 0.74 under misalignments, leading to over 100% change of the unregulated output voltage if the system is series–series tuned. In contrast, a laboratory prototype of the proposed system demonstrates a stable output voltage within ±9% of fluctuation around 13.25 VDC.

Improved perturb and observe maximum power point tracking technique for solar photovoltaic power generation systems

The primary concerns in the practical photovoltaic (PV) system are the power reduction due to the change in operating conditions, such as the temperature or irradiance, the high computation burden due to the modern maximum power point tracking (MPPT) mechanisms, and to maximize the PV array output during the rapid change in weather conditions. The conventional perturb and observe (P&O) technique is preferred in most of the PV systems. Nevertheless, it undergoes false tracking of maximum power point (MPP) during the rapid change in solar insolation due to the wrong decision in the duty cycle. To avoid the computational burden and drift effect, this article presents a simple and enhanced P&O MPPT technique. The proposed technique is enhanced by including the change in current (dI), in addition to the changes in output voltage and output power of the PV module. The effect of including the dI profile with the traditional method is explained with the fixed and variable step-size methods. The mathematical expression for the drift-free condition is derived. The traditional boost converter is considered for validating the effectiveness of the proposed methods by employing the direct duty cycle technique.

Collaborative Filler Network for Enhancing the Performance of BaTiO3/PDMS Flexible Piezoelectric Polymer Composite Nanogenerators.

Wearable sensors are gaining attention in human health monitoring applications, even if their usability is limited due to battery need. Flexible nanogenerators (NGs) converting biomechanical energy into electrical energy offer an interesting solution, as they can supply the sensors or extend the battery lifetime. Herein, flexible generators based on lead-free barium titanate (BaTiO3) and a polydimethylsiloxane (PDMS) polymer have been developed. A comparative study was performed to investigate the impact of multiwalled carbon nanotubes (MWCNTs) via structural, morphological, electrical, and electromechanical measurements. This study demonstrated that MWCNTs boosts the performance of the NG at the percolation threshold. This enhancement is attributed to the enhanced conductivity that promotes charge transfer and enhanced mechanical property and piezoceramics particles distribution. The nanogenerator delivers a maximum open-circuit voltage (VOC) up to 1.5 V and output power of 40 nW, which is two times higher than NG without MWCNTs. Additionally, the performance can be tuned by controlling the composite thickness and the applied frequency. Thicker NG shows a better performance, which enlarges their potential use for harvesting biomechanical energy efficiently up to 11.22 V under palm striking. The voltage output dependency on temperature was also investigated. The results show that the output voltage changes enormously with the temperature.

Mathematical Modeling of Buck Converter with Relay Feedback

This paper proposes the idea of mathematical modeling of the buck converter. The modified approach is achieved through the relay feedback (RF) method and the changes are introduced on the converter output with a soft start. Mathematical modeling of the buck converter is achieved by the state-space model (SSM) and converter’s transfer function (TF) to attain stability. By iteration, the proportional-integral (PI) parameters are tuned by a controller that is incorporated in the RF. The output voltage changes are introduced by maintaining the relay-tuned PI control. The concept requires small tuning times which is obtained at a reduced cost. The effectiveness of buck converter using RF is validated in simulation and hardware.

Designing Low-Cost Arduino Powered Spin Coater for Thin Film Deposition

In the present work, we have designed a low-cost spin coater using the Arduino Uno board. The advantage of selecting Ardunio is, it has pulse width modulation (PWM) based pins. Depending on the width of the pulse, the output voltage changes which will intern changes the speed of the DC motor connected to the PWM pin. The thickness of deposited film using spin coater depends on RPM and duration of rotation. The rotation of the substrate during deposition has three stages a gradual increase in RPM, maintaining constant RPM over a while, and a gradual decrease in RPM. All these parameters can be controlled by an Arduino board. An Aluminum doped Zinc Oxide film was deposited on glass substrate using Arduino based spin coater. X-ray diffraction, UV – VIS spectroscopy, and FTIR methods were used as characterization techniques. Hexagonal crystal structure of deposited AZO layer was confirmed by XRD and optical band gap, transparency were calculated by UV-VIS spectroscopy.