Voltage Generator Research Articles

Nafion-mediated barium titanate-polymer composite nanofibers-based triboelectric nanogenerator for self-powered smart street and home control system

Incorporation of inorganic materials into a polymer matrix has drawn significant interest, as the process can improve the mechanical and triboelectric properties of composite products. However, well dispersion and long-term stability of the developed composites remain a challenge. In this paper, we propose a novel Nafion-functionalized barium titanate nanoparticles (BaTiO3 NPs)/polyvinylidene fluoride (PVDF) composite nanofibers based high-performance triboelectric nanogenerator (NBP-TENG), which can serve as a self-powered human-machine interface for a smart control system. Specifically, our method of introducing Nafion provides an excellent dispersion of BaTiO3 into the PVDF matrix. As a result, a highly stable dispersion is maintained for almost 6 months without any noticeable precipitation or agglomeration. Consequently, the excellent dispersion enhances the effective stress transfer at the interface between the BaTiO3 and PVDF, resulting in the remarkably improved negative surface potential in the BaTiO3/PVDF homogeneous composite nanofibers. The NBP-TENG allows the generation of high output voltage, current density, and power density of 307 V, 1.8 µA/cm2, and 1.12 mW/cm2, respectively, which are enhanced by ∼ 6.3, 7.1, and 3.7 times, respectively, compared to pristine PVDF nanofibers. The NBP-TENG is capable of powering dozens of commercial LEDs connected in series by manual tapping and demonstrates stable output performance even after 10,000 cycles of repeated contact separation. Moreover, the NBP-TENG can be utilized as a self-powered human-machine interactive interface for smart street and home control systems, with the advantages of promising reliability, cost-effectiveness, energy efficiency, and practicality.

Great new generation carbon microsphere-based composites: Facile synthesis, properties and their application in piezo-electric energy harvesting

In this work, new generation carbon microspheres (CMS) based rubber composites have been obtained for flexible electronics applications such as stretchable piezo-electric energy harvesting devices. The rubber matrix used was room-temperature-vulcanized silicone rubber (RTV-SR). Herein, the CMS was exploited as a source of reinforcement and conductive material for improving mechanical and electrical properties. For example, the compressive modulus was 2.1 MPa (virgin) and increased to as high as 3.3 MPa (5 phr CMS). Similarly, the Shore A hardness was 26 (virgin) and increased to 40 (5 phr CMS). The electrical properties were also influenced significantly with electro-chemical resistance of 22.05 kΩ (virgin) and decreased to 15.91 kΩ (5 phr CMS). CMS's XPS spectrum revealed a high carbon-to-oxygen atomic ratio (74.47 and 25.53 %). The carbon and oxygen-containing functional groups of CMS acted as a catalyst to improve interfacial interaction of the composites thereby leading to higher mechanical properties. These improved properties were explored in the real-time device and output voltage generation with high durability was tested. From measurements, it was found that the output voltage from the piezo-electric energy harvesting device was around 1.25 V and high durability of 0.5 million cycles was reported.

Artificial intelligence based nonlinear control of hybrid DC microgrid for dynamic stability and bidirectional power flow

Conventional power generation resources are depleting rapidly and world power sector has been moving towards renewable energy sources (RESs). In this paper nonlinear control for renewable energy and hybrid energy storage system (HESS) based DC microgrid (DCMG) has been presented. PV and wind energy being the renewable sources whereas fuel cell, battery and ultracapacitor constitute the HESS. The global mathematical model of the said system has been presented. Datasets of varying solar irradiance and temperature have been trained by Artificial Neural Network for the reference voltage generation of PV. Integral terminal sliding mode controller (ITSMC) has been proposed for the output DC bus voltage regulation. Lyapunov stability criterion has ensured the overall stability of the system. A comparison of ITSMC with SMC and Lyapunov redesign controller has also been presented. Grid connected battery electric vehicle charger with grid to vehicle (G2V) and vehicle to grid modes (V2G) has been presented being an application of DCMG. The proposed system has been validated by using MATLAB/Simulink (2020b). Moreover, the hardware in loop setup has been used to observe the real time applicability of the proposed controller.

Power Generation and Microbial Community Shift According to Applied Anodic Potential in Electroactive Biofilm Reactors Treating Synthetic and Domestic Wastewater

This study investigated the effect of initially set anodic potentials (−0.3, −0.2, −0.1 and +0.1 V) on voltage production and microbial community in electroactive biofilm reactors (EBRs) treating synthetic and domestic wastewater (WW). In phase 1, EBRs were acclimated with different anodic potentials for synthetic and domestic WW. EBR (SE4) poised with +0.1 V showed the highest maximum power density (420 mW/m2) for synthetic WW, while EBR (DE3) poised with −0.1 V showed the highest maximum power density (235 mW/m2) for domestic WW. In phase 2, the EBRs were operated with a fixed external resistance (100 Ω for synthetic WW and 500 Ω for domestic WW) after the applied potentials were stopped. The EBRs showed slightly different voltage productions depending on the WW type and the initial anodic potential, but both EBRs applied with +0.1 V for synthetic (SE4) and domestic (DE4) WW showed the highest voltage production. Principal component analysis results based on denaturing gel gradient electrophoresis band profiles showed that the microbial community was completely different depending on the WW type. Nevertheless, it was found that the microbial community of EBRs applied with a negative potential (−0.3, −0.2, and −0.1 V) seemed to shift to those of EBRs applied with a positive potential (+0.1 V) regardless of WW type. Therefore, positive anodic potential is an important operating factor in electroactive biofilm development and voltage generation for rapid start-up.

Real-Time Collection of Conidia Released from Living Single Colonies of Podosphaera aphanis on Strawberry Leaves under Natural Conditions with Electrostatic Techniques.

Powdery mildew fungi produce progeny conidia on conidiophores, and promote the spread of powdery mildew diseases by dispersal of the conidia from conidiophores in the natural environment. To gain insights and devise strategies for preventing the spread of powdery mildew infection, it is important to clarify the ecological mechanism of conidial dispersal from conidiophores. In this study, all of the progeny conidia released from single colonies of strawberry powdery mildew fungus (Podosphaera aphanis (Wallroth) U. Braun and S. Takamatsu var. aphanis KSP-7N) on true leaves of living strawberry plants (Fragaria × ananassa Duchesne ex Rozier cv. Sagahonoka) were consecutively collected over the lifetime of the colony with an electrostatic rotational spore collector (insulator drum) under greenhouse conditions, and counted under a high-fidelity digital microscope. The insulator drum consisted of a round plastic container, copper film, thin and transparent collector film, electrostatic voltage generator, and timer mechanism. When negative charge was supplied from the voltage generator to the copper film, the collector film created an attractive force to trap conidia. The electrostatically activated collector film successfully attracted progeny conidia released from the colony. Experiment was carried out at just one colony on one leaf for each month (in February, May, July, October, November, and December in 2021), respectively. Each collector film was exchanged for a new collector film at 24 h intervals until KSP-7N ceased to release progeny conidia from single colonies. Collection experiments were carried out to estimate the total number of conidia released from a single KSP-7N colony over a 35-45-day period after inoculation. During the fungal lifetime, KSP-7N released an average of 6.7 × 104 conidia from each of the single colonies at approximately 816 h. In addition, conidial release from KSP-7N colonies was largely affected by the light intensity and day length throughout a year; the number of conidia released from single KSP-7N colonies in night-time was clearly smaller than that in daytime, and the time of conidial release from single KSP-7N colonies was shorter by approximately 2 to 4 h in autumn and winter than in spring and summer. The ecological characteristics related to conidial releases from KSP-7N colonies will be helpful information for us to successfully suppress the spread of strawberry powdery mildews onto host plants under greenhouse conditions.

Voltage generation induced by thermo-driven ion solution flow in CNTs for low-grade thermal energy harvesting

The flow induced voltage generation has been regarded as an advanced energy harvesting technology at nanoscale with broad application prospects. The ionic liquid flow inside carbon nanotubes (CNTs) can be potential to harvest the low-grade thermal energy. In this work, the flow of aqueous solution of sodium chloride (NaCl) driven by the temperature gradient and the performance of voltage generation in CNT are investigated with the non-equilibrium molecular dynamics (MD) simulations. The accumulated displacement and the number density distribution of ions and water molecules are recorded in the simulations. The average flow velocities of ions are obtained and the flow-induced voltage is then predicted. The results show the thermal gradient along the axial direction of CNT drives the NaCl solution to flow from its hot end to cold one, which can drag the free charge carriers of CNT with a directional shift and generate a considerable voltage output. Moreover, the effects of temperature difference, CNT diameter and solution concentration on the ions flow and the flow-induced voltage are also studied. It is found the influence of the average flow velocity difference between Na+ and Cl− plays a dominant role on the flow-induced voltage, the different influencing factors show different rules in the variation of voltage generation. The findings in this work can contribute to the development of new energy-harvesting nano-devices for the low-grade thermal energy.

Enhancement of inter‐area oscillation damping by wide‐area controlled hydropower plants

This paper examines how the combined use of hydro governors and a wide-area damping controller (WADC) can improve the damping of inter-area oscillations in power systems. Such oscillations can endanger the stability of power grids, thus damping them is a high priority for transmission system operators (TSO). To ensure that low-frequency oscillations decay as fast as possible, a modal linear quadratic Gaussian (LQG) is proposed as a wide-area controller approach. Using the 10-machine New England Test System, the combined application of the WADC in hydropower plants via generator excitation as well as via the hydro governor is examined for their effectiveness in terms of damping capability. In order to minimize the number of essential PMUs in power systems for the model-based WADC, the residue-based input/output signal selection method is applied. To increase the robustness against large disturbance faults, the generator voltage as additional signal is utilized for the WADC. For controller performance and robustness, the verification has been done under various operating points, tie-line failures as well as different PMU delays. The successful damping of the inter-area oscillation by means of wide-area controlled hydropower plants has been also demonstrated through a nonlinear time domain simulation.

Boosted Output Voltage of BiSbTe‐Based Thermoelectric Generators via Coupled Effect between Thermoelectric Carriers and Triboelectric Charges

AbstractThe present work demonstrates the very first approach to enhancing the output voltage of a thermoelectric generator by introducing highly charged polyimide‐based dielectrics. High charge density over 320 µC m−2 in C60‐containing block polyimide (PI‐b‐C60) having excellent charge retention characteristics is obtained through an ion injection process, attached at the cooling part of a thermoelectric generator consisting of Cu/p‐type BiSbTe/Au/Cr/SiO2/Si. This significantly increases the electric potential difference across the thermoelectric generator (TEG) from 4.2 to 8.2 mV at the temperature difference of 20 K, and this increase can be maintained over 1 day. Density functional theory studies support that the enhancement depends on the dielectric constant and the insulating properties of the dielectric. Finally, a TEG consisting of 81 p‐type BiSbTe legs with PI‐b‐C60 generates an output voltage of 0.632 V, and the charged energy of the 10 mF‐capacitor is boosted by 30 s. These results demonstrate the possibility of large‐area TEG fabrication without the need for modification of the TE materials by introducing a new mechanism which is based on the coupling effect between thermoelectric carriers and triboelectric charges.

Four-point bending piezoelectric energy harvester with uniform surface strain toward better energy conversion performance and material usage

Improving the energy conversion efficiency of piezoelectric energy harvesters is of great importance, and one approach is to make more uniform use of the working material by ensuring a uniform strain state. To achieve better performance, this paper presents a four-point bending piezoelectric energy harvester with extensive investigation and modeling to identify the influential parameters. An electromechanical analytical model is presented and verified by experimental data. The frequency-domain method extracts the solutions for a general time-variable force and impact. Four-point bending is compared with the standard cantilever harvesters regarding voltage generation, mechanical strain, and figure of merit. Strain contours are analyzed and interpreted for this innovative approach, and the power generation by the optimal resistance load is studied. Dimensionless parameters are introduced and investigated to find the optimal operating conditions for the four-point bending harvester. Finally, the four-point bending performance and the best figure of merit are discussed with a view to the long-term fatigue life of the harvester. The results show that in the best four-point bending energy conversion conditions; the energy conversion coefficient is more than three times higher than that of typical cantilever energy harvesters. The results also illustrate that the axial strain experienced in a standard cantilever harvester is more than three times higher than that of the four-point bending harvester, suggesting the latter device may have favorable fatigue performance. Overall, the presented piezoelectric harvester has improved energy conversion efficiency and experiences a reduced and uniform surface strain, making it appropriate for high-efficiency energy harvesting systems.

Bioelectricity generation by microbial degradation of banana peel waste biomass in a dual-chamber S. cerevisiae-based microbial fuel cell

Microbial fuel cells (MFCs) are considered as an emerging and cost-effective technology for treating organic waste along with bioelectricity generation. The present study evaluates the performance of S. cerevisiae-based H-shaped microbial fuel cell with banana peel waste as substrate, operated for 30 days in three cycles. Dried banana peel and banana slurry substrates were prepared with initial COD of 1126 ± 41 mg. L−1 and 1366 ± 64 mg. L−1 respectively. Dried banana peel powder was fed into two MFCs, one with no inoculant and the other with S. cerevisiae. Dried banana peel powder without inoculant yielded negligible power output, whereas dried banana peel powder with S. cerevisiae generated a maximum power density of 2.2 ± 0.1 mW m−2. The banana peel slurry was fed into two different MFCs one was with S. cerevisiae and another was without S. cerevisiae. Banana slurry with S. cerevisiae generated a maximum power output of 86.9 ± 0.4 mW. m−2. Banana peel slurry without inoculation, generated a maximum power output of 44.6 ± 0.8 mW. m−2. Microbial community analysis indicated that the high-power output obtained from banana slurry-based MFCs was due to the presence of indigenous microbial consortia. Up to 70–88% COD removal was recorded in MFCs with banana slurry, however, 18–44% of COD removal was observed in MFCs with dried banana peel powder. It was also observed that the simple saccharides available in banana peel waste were consumed by S. cerevisiae and other indigenous microbes in the anode chamber. The microbial community released electrons in the anode chamber, which were responsible for voltage generation in MFC.

Volt/Var control and energy management in non-interconnected insular networks with multiple hybrid power plants

This paper proposes a sensitivity-based optimization approach for the energy management and volt/var control of islanded networks powered by a thermal generator and several hybrid power plants (HPPs). Specifically, the method optimizes, in a 24-hour horizon, the active and reactive power of the HPPs, the output voltage of the thermal generator, as well as the settings of local voltage controllers e.g., step voltage regulators, capacitor banks, in order to minimize the generation cost of thermal generators and satisfy the following constraints: a) the technical limits of the diesel generators, b) the maximum direct penetration limits of the renewables, c) the state of charge limits of energy storage systems, d) the three-phase voltage limits of all the buses of the network. Simulations were executed in a modified islanded version of the IEEE 8500-node network, consisting of a diesel generator and multiple HPPs with various renewable generators and storage devices. According to the simulations, the proposed method minimizes the generation cost of diesel generators, while satisfying all the aforementioned technical constraints. In contrast to the existing optimization methods e.g., PSO, MINLP, which are practically inapplicable in large networks with a 24-hour optimization horizon, the proposed method presents very low computation time.

Effects of Sn doping on piezoelectric power generation and energy density of flexible BaTiO3 thin films

Ferroelectric thin films find applications in numerous areas, including sensors and energy storage devices. To address the toxicity associated with thin films such as Pb(Zr,Ti)O3, developing Pb-free ferroelectric thin films with enhanced physical properties is necessary. Herein, the piezoelectric power generation and energy density of Sn-doped BaTiO3 (SBTO) thin films with varying Sn doping concentrations were studied. Polycrystalline SBTO thin films with Sn doping concentrations of 0%, 5%, 10%, and 15% were deposited on flexible Pt/mica substrates with a preferential (111) orientation. The SBTO thin film with a Sn doping concentration of 5% exhibited the highest remanent polarization (Pr) in the ferroelectric hysteresis loop. In contrast, the SBTO thin films with Sn doping concentrations of 10% and 15% exhibited reduced Pr owing to the formation of 90° domains. The lowest Pr was observed for the SBTO thin film with 15% Sn. With an increase in the Sn doping concentration, the piezoelectric coefficient (d33) increased due to the formation of a-domains. Owing to the high concentration of a domain, the SBTO thin film with 15% Sn exhibited the highest d33 and consequently, the highest piezoelectric power generation voltage. Moreover, the minimum Pr of the film with 15% Sn facilitated an increase in energy density and efficiency.

Stabilization of the Output Voltage of an Autonomous Asynchronous Generator of a Wind Power Plant

Stabilization of the Output Voltage of an Autonomous Asynchronous Generator of a Wind Power Plant

Self-Operating Flyback Converter for Boosting Ultra-Low Voltage of Thermoelectric Power Generator for IoT Applications

This article presents a novel self-operating flyback converter to boost the ultra-low voltage produced by thermoelectric power generator (TEG). The proposed converter uses dual transformer, one for low-voltage startup and other to extract power from TEG. The use of separate transformer provides high-voltage transfer ratio, reduces high series resistance loss, and brings down the input impedance of circuit. The copper wire wounds ferrite toroid core transformer provides very low series resistance and negligible core loss, which improves the circuit efficiency. This boost converter operates with an input voltage range of 22–300 mV and provides maximum output power of 0.073 – 147 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\rm{mW}}$</tex-math></inline-formula> correspondingly. The peak efficiency of 68% with output power of 1.32 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\rm{mW}}$</tex-math></inline-formula> (voltage ∼1.83 V) is achieved at an input voltage of 50 mV. For regulated output voltage, a feedback loop is used to keep output voltage constant during sudden voltage rise of TEG. The proposed circuit uses discrete components, ferrite toroid core, and PCB, which has lower cost than available energy harvester module, which uses energy harvesting ICs, discrete components, and tiny transformer. The lower startup voltage, higher output power, and voltage with high conversion efficiency of this boost converter maximize the applications potential of the TEG as a portable power source for Internet of Things (IoT) devices.

Three-Level T-Type qZ Source Inverter as Grid-Following Unit for Distributed Energy Resources

Distributed energy resources (DERs), such as solar photovoltaics (PVs), are required to achieve a high performance and an efficient use of generated renewable power in grid-integrated applications, both in normal and fault operating conditions. In this article, a grid-following (GFL) multifunctional control strategy for a three-phase three-level T-type quasi-impedance source inverter (3L-T-type qZSI) is studied through simulation and experimental tests. The GFL functionality is achieved by a proportional–integral (PI)-based dq current controller for the active and the reactive power tracking. A PI-based dc controller is used for the dc-link voltage control by taking advantage of the quasi-impedance source (qZS) network ability for input voltage boosting. The dc–ac power conversion is accomplished through a space vector pulsewidth modulation (SVPWM) with inner capacitors voltages balancing capability and minimum common-mode voltage (CMV) generation. Besides, a low-voltage ride-through (LVRT) strategy was implemented to fulfill the fault requirements imposed by the Spanish standard. The simulation and experimental results demonstrate the abovementioned functionalities and validate the stability and good dynamic response of the grid-connected 3L-T-type qZSI. Thus, this work supposes a novel contribution due to the few works previously reported in the literature concerning the performance of this relatively recent inverter topology in grid-tied applications.

Research and application of high voltage measurement technology in DC UHV preventive test

With the state’s high attention to clean energy and the requirement to reduce the loss of power grid transmission lines, DC UHV has developed rapidly in recent years. It refers to DC transmission and related technologies with voltage levels of ±800 kV (±750 kV) and above. In the power system, DC high-voltage transmission is inseparable from power equipment, but the higher the transmission voltage level, the higher the voltage of DC withstand voltage preventive test. Before the transmission of UHV DC transmission lines, if the DC voltage withstand device is 800 kV or above, the voltage withstand test shall not be carried out for the high-voltage line. The traditional direct comparison method using voltage divider cannot be used to measure the DC output voltage of DC UHV withstand voltage device on site. This paper analyzes the method of full coverage of DC UHV system in limited voltage range and the method of out of range calibration using scale factor. In order to solve the problem of voltage traceability in the DC high voltage generator, especially the voltage traceability of the field DC UHV device, when the voltage output range of the calibrated DC high voltage generator exceeds the measurement range of the standard, the standard value of the voltage calibration point beyond the range can be determined by comparison and obtained through the linearity test. The comparison with the standard shall be conducted at a voltage not lower than 20% of the rated voltage of the calibrated DC high voltage generator, and compared to the maximum voltage of the standard voltage divider. The comparison is carried out at a (a ≥ 2) voltage point. When comparing at a point, the highest voltage level is equal to the upper limit of the standard. Under a voltage point, according to the mathematical relationship between the voltage standard value of the tested device and the current flowing through the linear load resistance, the fitting function can be obtained through the linear regression method. For b (b ≥ 4) calibration points beyond the measurement range of DC standard voltage divider, the standard value can be “extrapolated” from the linear load resistance current and the fitting function Yang (2002). Through comparison and verification, the method is feasible, which is of great significance to promote the compilation of calibration specification for DC high voltage generator.

Enhancement of voltage generation for thermoelectric generator using parabolic pulsed heating

This paper presents the results of investigations of the impact of parabolic pulsed heating on output voltage levels of a thermoelectric generator. The experiment was set up and tested under different test conditions. The output voltage levels were investigated. The experimental results showed that applying parabolic pulsed heating of 40, 60, 80 and 100 °C significantly maintained the output voltage levels of thermoelectric generator at about 80-95% which was different from steady heating case which was about 10-30% of maximum voltage level. Moreover, the parabolic pulse heating technique allows the heatsink to not be heated continuously and then the high temperature could be released out from a heat exchanger outside the heating period. This causes the next heating period to have a temperature difference between both sides of the device, and for that reason, could provide more power and efficiency.

Application of organic additives as voltage enhancers for vermicompost-derived bio-battery

A bio-battery which is powered by organic compounds provides a clean alternative renewable power source. Huge amount of green wastes around Universiti Teknologi PETRONAS (UTP) campus such as fallen leaves and grass clippings provides an opportunity for waste conversion into value-added products using an eco-friendly composting method called vermicomposting where locally abundant earthworms are added to speed up the breakdown the organic wastes into vermicompost. Recent studies revealed the potential of vermicompost to be used as green electrolyte of bio-battery instead of being solely used as fertilizer. However, the voltage produced from bio-battery is found typically lower and less stable than conventional batteries. The main goal of this research work is therefore to enhance the voltage generation of bio-battery derived from UTP vermicomposts. As a start, good quality vermicompost was produced from available green wastes in UTP compound at optimum carbon-to-nitrogen (C:N) ratio of 30. Next, the humic acid and fulvic acid were be extracted from the vermicompost to be used as the bio-battery’s electrolytes. Different organic additives were added into the electrolyte to determine their suitability as voltage enhancers via voltage profiling. Compost quality was established by final C:N ratio, humic and fulvic acid yield and moisture content analysis in comparison to commercial vermicompost. Key highlights of the project include vermicompost reached maturation on day 41, mass reduction of 18%, and humic and fulvic acid yields at 3.41% and 0.38%. The highest voltage recorded was 0.62 V for humic acid electrolyte with fruit enzyme additive. This approach has multi-fold benefits of cutting down labour requirement, promoting eco-friendly waste management and generating value-added products from waste.

COMPUTER MODEL OF IONIZER

Depending on the field of application and nature of high voltage generation technologies used in various economic sectors, several requirements are imposed, in particular, requirements such as service life, environmental safety, work efficiency and energy efficiency. In this work, a computer model for generating high voltages that are safe for humans using transistors designed to amplify semiconductor electrical signals is described.

Performance analyzes of a compact pico hydropower plant with a wide operating range

&lt;span&gt;This paper analyzes the performance of a pico hydropower plant consisting of an axial hydro turbine integrated with a permanent magnet generator (PMG) and connected to a power converter. The proposed system is aimed to obtain a wide system operation range to gain more power captured while maintaining time-harmonic distortion in voltage (THDv) that meets the standard. The PMG specification is 1 kW, 1 phase, 235 V, 50 Hz, 83 rpm. The design and simulation of PMG were carried out by analytical and numerical calculations using FEMM 4.2. The power converter was simulated using PSIM and functions to reduce the THDv and pass the generator voltage between 50–500 V. The results show the THDv of the generating system at the upper and lower limits of the passed voltage having a THDv below 5%. Meanwhile, the PMG performance characteristics at various currents and rotations produce efficiency of 87.20% at nominal current. From these results, it can be concluded that the pico hydropower plant works well as desired.&lt;/span&gt;