Output Voltage Research Articles

Amplification of very low output voltages of PV panels using a Duffing oscillator

We are interested in the amplification of very low voltages produced by solar cells during sunset or weak sunshine. The study uses a device consisting of a Duffing oscillator, which amplifies and automatically regulates a low-voltage input, an inverter that reverses the negative voltage of one of the outputs of the oscillator, and a summing device to add the voltages of the two oscillator outputs. Experimental and theoretical investigations are conducted, and it is observed from the results that the output voltage can reach to 7.03V for an input voltage of 0.43V, i.e. a gain of 24.3dB. Furthermore, we observe from the amplification factor, and the behavior of the cyclic ratio that the whole system nonlinearly amplifies the input voltage with a large factor for weak inputs. We finally compare the results produced by the proposed system and those produced by a conventional boost converter at very low voltages. It then results that the Duffing oscillator provides large amplification factors for low voltages.

Enhanced performance of polydimethylsiloxane-based triboelectric nanogenerator using BaTiO3/MWCNTs

Triboelectric nanogenerators (TENGs) that operate in the contact-separation mode are widely utilized for energy harvesting owing to their simple structure, excellent durability, and high energy-conversion efficiency. This study investigated the enhanced performance of TENGs using polydimethylsiloxane (PDMS) incorporating barium titanate (BTO) and multiwalled carbon nanotubes (MWCNTs). The negative triboelectric layer, comprising PDMS with BTO and MWCNTs, and aluminum foil as both the positive triboelectric layer and electrode, were optimized to improve the TENG performance. The optimal composition of PDMS incorporating 0.01 wt% MWCNTs and 10 wt% BTO yielded output voltage and current of 394.75 V and 28.24 µA, respectively. Further enhancement was realized via the application of radio frequency plasma treatment, which increased the surface roughness and fluorine incorporation. Consequently, the output voltage and current improved to 421.06 V and 32.33 µA, respectively, with a peak power density of 4.76 W/m2 at 10 MΩ. The optimized TENG maintained consistent performance over 2000 cycles and successfully illuminated commercial LEDs, thereby demonstrating its potential for practical energy-harvesting applications.

High efficiency AOT-controlled boost converter with pseudo-constant switching frequency

An on-time generator for boost converters is proposed to achieve an adaptive on-time (AOT) control with pseudo-constant frequency in continuous conduction mode (CCM). Since the first-order parasitic effect of the components and devices is considered in the design of the on-time generator, the switching frequency (fsw) variation of the boost converter in CCM can be better suppressed with the load current (ILOAD), input voltage (VIN) and output voltage (VOUT) changes, which can effectively solve the EMI noise problem. In addition, the idea of capacitor pre-charging is applied to simplifying circuit complexity. Meanwhile, an on-demand modulation strategy is applied to improve the conversion efficiency. Simulation results show that the boost converter based on the proposed on-time generator can realize the fsw variation of 0.4 % in case of 200 mA ILOAD change. Moreover, the VIN may range from 0.8 to 1.5 V, the VOUT is set to 1.8 V, and the peak efficiency of the simulation is 96.9 %.

Cobalt Ferrite@Barium titanate core-shell nanoparticles empowered triboelectric electromagnetic coupled nanogenerator for self-powered electronics

In pursuing sustainable energy solutions for wearable technology and Internet of Things (IoT) devices, achieving high power in self-powered electronics is a significant challenge. This study introduces a novel hybrid nanogenerator by integrating a triboelectric nanogenerator (TENG) and an electromagnetic generator (EMG) to achieve both high voltage and high current outputs simultaneously. The cobalt ferrite barium titanate (CoFe2O4@ BaTiO3) core–shell nanoparticles (NPs) were chosen for their unique ability to enhance the system’s performance by combining triboelectric, piezoelectric, and electromagnetic properties. The BaTiO3 shell exhibited robust triboelectric and piezoelectric properties essential for TENG operation, while the CoFe2O4 core, influenced by the EMG’s magnetic field, induces additional static charges, significantly boosting overall energy conversion efficiency. The TENG and EMG in the combined system operate together in a contact-separation mode, where their in-phase output signals are seamlessly combined via a double bridge rectifier, resulting in a robust power output of 37.7 mW and a power density of 1.86 mW/cm2, with cycling stability of over 10,000 cycles. The uniquely designed TENG-EMG combined nanogenerator (C-TENG) exhibited striking adaptability, effectively operating across different low-to-high frequencies and load situations while constantly powering portable electronic devices. This innovative approach meets the high energy demands of modern self-powered electronics with exceptional efficiency, durability, and high-power density, positioning it as a versatile solution for wearable biomechanical energy harvesting.

Comprehensive Analysis of Faults and Diagnosis Techniques in Cascaded Multi-Level Inverters

Reliability is a crucial factor to consider for multi-level inverters (MLIs) used in industrial applications. With the increasing number of power semiconductor devices, the potential for defects to significantly degrade the overall system is heightened. A highly effective fault-detection technique is required to minimize the impact of faults. This paper provides a comprehensive overview of the fundamental principles of multi-level inverters and the various sorts of faults that can occur in multi-level inverters. This study provides a comprehensive analysis of five-level cascaded H-bridge multilevel inverters (MLIs) under both normal and defective conditions. The paper outlines a fault-detection method that utilizes total harmonic distortion and a normalized output voltage factor. In addition, the paper discusses a fault-isolation strategy that relies on reducing amplitude modulation. This method leads to the development of a fault-tolerant inverter. The utilization of level-shifted pulse-width modulation (LSPWM) technology is employed for the purpose of switching operations. LSPWM is the most appropriate technique for MLIs that require a low amount of computational resources. The fault-diagnosis approach given is suitable for MLI-based drives, grid-connected operations, and other applications. This paper presents a comprehensive examination of the 5L-CMLI (5-Level Cascaded Multi-Level Inverter) under various fault scenarios in CMLI. Subsequently, various fault diagnosis approaches will be examined, including their advantages and disadvantages. The paper discusses several defects that can occur in the Insulated Gate Bipolar Transistor (IGBT) of a Current Mode Logic Inverter (CMLI), and also presents a design for a reliable fault diagnosis system. Furthermore, this analysis examines several fault detection strategies in CMLI, categorized according to open-loop and closed-loop dynamic systems fault classifications.

Polymerized lignin based carbon nanofiber for high-performance energy generator and storage

Lignin is an ideal precursor for the preparation of lignin-based materials. However, the lack of molecular weight, thermal stability and spatial configuration of lignin hinder the practical application of lignin in lignin-based carbon materials. Herein, a novel and effective strategy for preparing high-performance lignin-based carbon nanofibers (CFs) is designed. Lignin samples with different chemical structures are prepared by polymerization modification and fractionation. This strategy completely gets rid of the dependence on petroleum-based polymers in the electrospinning process, and makes the lignin-based CFs show good performance in energy storage, temperature sensor, and moisture power generation. The specific capacitance and energy of lignin-based supercapacitors reach 357.2 F/g and 31.5 Wh/kg, respectively. The CFs exhibit good flame retardancy and thermal sensitivity, and the response time is 1 s. In addition, moisture power generators assembled with CFs exhibit great potential. The output voltage of moisture power generators has a linear relationship with the number of devices. With the increase of series equipment, the output voltage of 5 series moisture power generators is 4.7 V. This work provides a new approach to prepare high-performance lignin-based carbon nanofibers, which has a good application prospect in the fields of energy storage, sensing and power generation.

Optimisation of LED luminaires renewal interval based on proposed CLO adjustment method

A considerable part of electrical power is consumed in lighting systems. Electrical power usage and, as a result, generation is proportional to CO2 emissions. CO2 emissions result in climate change. Many countries encouraged people to use modern light sources, including LEDs, to increase the efficiency of lighting systems. An LED, during its long life, is subjected to gradual degradation. Its degradation can be understood from its radiant flux decrement. Some standards, including LM 80-08, addressed this issue. Constant lumen output (CLO) drivers are used to deal with LED degradation issues. There is not much scientific research on the topic of CLO. This paper suggests a scientific approach to finding CLO's exact output voltage as a function of time during the LED lifetime, limiting energy consumption to the required value. Also, a method for finding the best time to replace LED luminaires to minimise the financial burden for the owners has been found. By optimising renewal time for LED luminaires, energy usage (CO2 emission) and end-of-life waste will be managed to the required value. In addition, for use in CLOs, the paper suggests adding more specified data to the LM 80-08 report.

Interfacial engineering of flexible Ag2-xSnxS on carbon fabric for enhanced wearable thermoelectric generator

Smart wearable devices are still powered by batteries requiring constant recharging, which is a key challenge faced in wearable technologies. Fabrication of flexible thermoelectric materials that can utilize body heat for wearable applications are an attractive alternative to batteries. Developing a thermoelectric material that is flexible, affordable, and has good performance remains a considerable challenge owing to the constrained thermoelectric efficiency of conducting polymers and the inherent rigidity of inorganic materials. Here, we have used a solvothermal technique to incorporate Ag2-xSnxS into conductive carbon fabric as a flexible thermoelectric material. To further enhance its thermoelectric performance, various concentrations of Ag2-xSnxS are grown on carbon fabric. The monoclinic phase of Ag2S on carbon fabric was verified by XRD analysis. After analyzing the thermoelectric characteristics of Ag1.84Sn0.16S, a maximum power factor of 110 μW/mK2 was observed for the SSS8 sample. This value is four times higher than the percentage of pristine Ag2S-CF. The W-TEG device fabricated using 3 pair modules produced an output voltage ranging from 0.09 to 1.5 mV across a temperature gradient of 3 to 8 K.

Output Voltage Ripple Suppression of PPSS-LCC Converter for Medical X-Ray Application Based on Repetitive Control

Output Voltage Ripple Suppression of <i>PPSS</i>-<i>LCC</i> Converter for Medical X-Ray Application Based on Repetitive Control

Implementation of the MPPT Particle Swarm Optimization Algorithm on a Hybrid PV-TEG Solar Panel with a DC-DC Buck Converter

Abstract Solar panels necessitate power control to locate the optimal working point amidst quickly changing voltages and diverse weather circumstances. This enables the system to adapt and sustain optimal performance in real-time. In order to address this issue, the optimization methodology known as Maximum Power Point Tracking (MPPT) is employed using an algorithmic artificial intelligence (AI) method. Particle Swarm Optimization (PSO) is a swarm intelligence technique that has effectively tackled diverse optimization issues in intricate systems. The DC-DC Buck Converter, which incorporates Maximum Power Point Tracking (MPPT), serves as an interface between the load and the photovoltaic (PV) system to control the output voltage of the system. A comparison is made between the performance of the Maximum Power Point Tracking (MPPT) technique using the Particle Swarm Optimization (PSO) algorithm and the hill climbing (HC) algorithm developed through MATLAB/SIMULINK simulations. The findings indicate that the PSO algorithm exhibits superior performance in terms of tracking time, output power, and stability, with little fluctuations or noise, as compared to the HC method. The tracking time is 0.02 seconds and 2.52 seconds, respectively. The power at constant irradiation is 14.49 Watts and 14.43 Watts. The power at irradiation variation is 6.98 Watt and 6.96 Watt. The PSO algorithm achieved a remarkable accuracy of 99.76% in this investigation, surpassing that of HC. This enhancement makes the system more effective in acquiring maximum power values.

Quasi Z source direct matrix converter based K- to three-phase wind energy conversion system using maximum constant boost current control modulation technique

The conversion system for wind energy has no restriction on the number of output phases. K numbers of output phases can be converted into standard grid-connected three-phase supply using a quasi-Z source direct matrix converter (QZSDMC). The obtained input supply may be five phases from the wind energy conversion system with continuously variable frequency as well as variable terminal voltages. Using the proposed QZSDMC converter with maximum constant boost current control modulation technique constant three-phase voltages as well as frequency can be maintained at the grid side. Additionally, the energy conversion system has high output voltage gain. The proposed converter as well as the modulation technique produces the maximum voltage transfer ratio of 1.05. The output voltage gain reached nearly 1.99 compared with the traditional power converters. The voltage THD and current THD are maintained within the acceptable limit of 5.3 and 3.6 respectively. The power factor have been maintained nearly unity throughout the all mode of operations. To stabilize the grid frequencies and grid voltages additional control blocks are used. This research article presents simulation results for the proposed QZSDMC converter with a maximum constant boost current control modulation technique. Also, the proposed scheme has been validated with suitable experimental results.

Full Range Operation of Simplified Flying-Capacitor Three-Cell Inverters With Five to Eight Output Voltage Levels

Full Range Operation of Simplified Flying-Capacitor Three-Cell Inverters With Five to Eight Output Voltage Levels

Integrated RES With Intelligent MPPT For Efficient Power Generation &amp; Wireless Transmission for PV Applications

The increasing global energy demand and the urgent need to shift to sustainable practices have made the integration of renewable energy sources (RESs) into distribution power systems imperative. This project's main objective is to implement rooftop photovoltaic (PV) systems as an essential part of low-voltage (LV) DC networks' building-integrated centralized generation Maximum Power Point Tracking (MPPT) using Artificial Neural Networks (ANNs) is used to maximize power extraction from photovoltaic (PV) panels and boost power generation efficiency, particularly in partially shaded circumstances. After that, the PV system's generated power is sent to a Luo converter, which effectively tracks and optimizes the power production. For wireless power transmission, the Luo converter's output is then fed into a high-frequency converter. This wireless power transmission improves the system's adaptability and scalability by facilitating smooth energy transfer without the requirement for physical connections. An isolation transformer is attached to the high-frequency converter's output in order to guarantee the system's dependability and safety. The high-frequency converter is isolated from the downstream components by the isolation transformer, which also offers protection against electrical risks. Finally, a battery made especially for use in electric vehicle (EV) applications receives the transformer's isolated output, which is also supplied to DC loads. Finally, we will use the MATLAB 2021a / Simulink program to do a number of numerical simulations in order to validate the suggested controls. The output voltage of 130v is stored in the battery if a voltage of 65 v is taken as output from the photovoltaic system.

Quasi-Resonant Fly-Buck Converter With Active Switching for Improved Output Voltage Boosting and Regulation

Quasi-Resonant Fly-Buck Converter With Active Switching for Improved Output Voltage Boosting and Regulation

Highly Efficient Wide Bandgap Perovskite Solar Cells With Tunneling Junction by Self-Assembled 2D Dielectric Layer.

Reducing non-radiative recombination and addressing band alignment mismatches at interfaces remain major challenges in achieving high-performance wide-bandgap perovskite solar cells. This study proposes the self-organization of a thin two-dimensional (2D) perovskite BA2PbBr4 layer beneath a wide-bandgap three-dimensional (3D) perovskite Cs0.17FA0.83Pb(I0.6Br0.4)3, forming a 2D/3D bilayer structure on a tin oxide (SnO2) layer. This process is driven by interactions between the oxygen vacancies on the SnO2 surface and hydrogen atoms of the n-butylammonium cation, aiding the self-assembly of the BA2PbBr4 2D layer. The 2D perovskite acts as a tunneling layer between SnO2 and the 3D perovskite, neutralizing the energy level mismatch and reducing non-radiative recombination. This results in high power conversion efficiencies of 21.54% and 19.16% for wide-bandgap perovskite solar cells with bandgaps of 1.7 and 1.8 eV, with open-circuit voltages over 1.3 V under 1-Sun illumination. Furthermore, an impressive efficiency of over 43% is achieved under indoor conditions, specifically under 200 lux white light-emitting diode light, yielding an output voltage exceeding 1 V. The device also demonstrates enhanced stability, lasting up to 1,200 hours.

Concentration calculation model for calibration of non-dispersive infrared gas detection system

Non-dispersive infrared (NDIR) gas detection systems have been extensively used for gas monitoring because they are considered the simplest approach with moderate sensitivity and fast response. Concentration calculation models for calibration are particularly important in NDIR gas detection systems because of the nonlinear relationship between the output voltage ratio and concentration. We propose a concentration calculation model with two fitting parameters for non-dispersive infrared gas detection systems, accounting for the fact that not all IR radiation that impinges upon the detector is absorbed by the gas and for the saturation effects in absorption peaks leading to the nonlinear relationship. Despite the small number of fitting parameters of the proposed concentration calculation model, it presents high quality curve fitting to experimental data. The performance of the proposed model is compared to that of other concentration calculation models.

Coupled Thermo-Electric-Elastic Piezoelectric Vibration Energy Harvester With Axial Movement: Modeling, Verification, and Analysis

Abstract In the field of rail transport and aerospace field, vibration energy harvesting is inevitably subjected to coupled excitations, including train wheel–track interaction induced friction heat and forced vibration, periodic thermal radiation, and vibration excitation. This paper investigates a coupled thermo-electric-elastic piezoelectric vibration energy harvester with axial movement under external heat flux and mechanical force load. The coupled forced vibration equation, coupled electric equation, and coupled thermoelastic heat conduction equation are derived and solved by Green's function theory. To analyze the effect of excitations on the response characteristics, the decoupled method is utilized to solve the coupled multi-field equations and obtain the displacement, electric, and temperature distribution closed-form solutions. The displacement coupling effect induced temperature distribution and the thermo-electric coupling effect triggered displacement are respectively decoupled and analyzed. The obtained closed-form temperature distribution and displacement solutions are verified by the finite element method. To further verify the obtained solutions, a numerical method is conducted by decoupling the coupled multi-field equations and comparing them with prior solutions. Additionally, the different height-to-length ratios, axially moving speeds, and external force load are analyzed in detail. The results indicate that the displacement, temperature distribution, and output voltage vary with external conditions due to the coupled multi-field effect. Overall, this work investigates the thermo-electric-elastic coupling effect on the axially moving piezoelectric energy harvesting, which is beneficial to promote theoretical investigations of the coupled multi-field energy harvesting system and accelerate the practical applications in the aerospace field.

An Optimization Design of Piezoelectric Hair Sensor for Oscillatory Flow Detection

Abstract Biological hair is widely found in nature, and they are responsible for sensing and responding to environmental stimuli in living organisms. By simulating biological hair characteristics, they develop hair flow sensor to achieve high sensitivity detection of environmental factors such as small motion and fluid flow field. Output signal is the key indicator of hair flow sensor, and the improvement of output signal is important to the design of hair flow sensor. The existing hair flow sensor sensing structure is generally straight hair, and the output signal is limited by the structure, and the response is small. Using the direct piezoelectric fiber as the initial configuration, we form a new piezoelectric curved fiber by modeling the secondary spline curve and control point. We propose an optimization model for piezoelectric functional hair design using axial strain as a target function. At 100Hz and 500Hz, the output voltage of the optimized model is much higher than that of straight, 10 times and 7 times that of straight, respectively; An optimized curved hair configuration is obtained in a specific frequency band from 1 Hz to 500 Hz, whose average voltage magnitude of 3.1×10−3 V is 4 times greater than that of the straight hair of 7.8×10−4 V with the same size. The curved hair flow sensor breaks the output limitation of traditional straight hair configuration.

Adaptive linear active disturbance-rejection control strategy reduces the impulse current of compressed air energy storage connected to the grid

The merits of compressed air energy storage (CAES) include large power generation capacity, long service life, and environmental safety. When a CAES plant is switched to the grid-connected mode and participates in grid regulation, using the traditional control mode with low accuracy can result in excess grid-connected impulse current and junction voltage. This occurs because the CAES output voltage does not match the frequency, amplitude, and phase of the power grid voltage. Therefore, an adaptive linear active disturbance-rejection control (A-LADRC) strategy was proposed. Based on the LADRC strategy, which is more accurate than the traditional proportional integral controller, the proposed controller is enhanced to allow adaptive adjustment of bandwidth parameters, resulting in improved accuracy and response speed. The problem of large impulse current when CAES is switched to the grid-connected mode is addressed, and the frequency fluctuation is reduced. Finally, the effectiveness of the proposed strategy in reducing the impact of CAES on the grid connection was verified using a hardware-in-the-loop simulation platform. The influence of the k value in the adaptive- adjustment formula on the A-LADRC was analyzed through simulation. The anti-interference performance of the control was verified by increasing and decreasing the load during the presynchronization process.

High-performance triboelectric nanogenerator with aminated barium titanate composite nanoparticles for early Parkinson’s disease diagnosis

High dielectric constant nanoparticles into polymer matrices have attracted much attention because this process can improve the nanofriction generator performance. However, the dispersion of the developed materials remains a challenge. In this paper, we present a novel high-performance nanofriction generator (FBT-TENG) based on composite nanoparticles of Amino-functionalized barium titanate and functionalized graphite oxide (FGO/ABTO) with Polyimide (PI) as substrate, which can be used as a sensor for intelligent monitoring systems. Specifically, we introduced amino groups on the surface of barium titanate to improve its dispersion in the PI solution, and the dual effect composite with functionalized graphite oxide improved the TENG performance of the PI film. Due to the FGO/ABTO synergy, the FBT-TENG can generate high output voltages, currents and power densities of 75 V, 13 µA and 4.6 W/m2, respectively, which is a 9 times increase in power density compared to the original PI film. FBT-TENG is capable of powering capacitors. In addition, the FBT-TENG can be used as a sensor to build an early Parkinson’s disease detection system, which provides a more convenient option for the early diagnosis of Parkinson’s patients and has the potential for a wide range of medical applications.