Output Voltage Of Generator Research Articles

High output voltage generation of over 5 V from liquid motion on single-layer MoS2

Water stores a large amount of clean energy in its dynamic forms. Owing to the wide availability of water and the rising demand for clean energy sources, the direct electricity generation from liquid motion by low-dimensional materials such as graphene has gained much interest. Electricity generation is induced by the motion of an electric double layer at the interface between the liquid droplet and solid surface. However, the output voltage with materials such as graphene is still limited to several hundred millivolts. In this report, we present a large-area single-layer MoS2 film grown by chemical vapor deposition as a nanogenerator, which is capable of generating a large output voltage of more than 5 V from the motion of an aqueous NaCl droplet. Our findings indicate that the high shunt resistance of MoS2 results in a large generated voltage. Furthermore, we demonstrate the possibility to scale up the MoS2 nanogenerator by arranging them in series and parallel connections, which respectively increase the output voltage and current, with a three-times increase with an array of three MoS2 nanogenerators. Our work opens the application of single-layer MoS2 for harvesting electricity from the dynamic movement of liquid, such as the capability to harvest ocean wave energy, which is also demonstrated here.

Comparison Performance of Nine Level Multilevel Inverter Using Bipolar and Unipolar Switching Schemes

Multilevel inverter structures have the advantages due to the ablility to operate at high dc-bus voltage. It is able to operate at higher power applications by using series connection of switching devices. In addition, multilevel inverter can generate output voltage with very low harmonic distortion and synthesis a staircase voltage waveform by having multiple voltage levels. Various multilevel inverter topologies are introduced; however, cascaded multilevel inverter is commonly used because it is easy to be implemented. In addition, multilevel inverter topologies are able to operate at lower switching frequency and it produces higher efficiency by producing lower switching dissipation. In this paper, MATLAB/Simulink is used to model the seven levels cascaded multilevel PWM inverter by using bipolar and unipolar switching techniques. The analysis of the cascaded multilevel inverter will be done on different types of non-linear loads such as R-load, RL-load and RC-load The THD of voltages and currents on each type of loads that are done and finally the results are compared.

A Flying-Inductor Hybrid DC–DC Converter for 1-Cell and 2-Cell Smart-Cable Battery Chargers

This article presents a new step-down hybrid converter topology that uses an input flying inductor and a switched-capacitor network to generate output voltages suitable for charging 1-cell (1S) or 2-cell (2S) batteries. The proposed topology relocates the inductor from the high-current output to the low-current input, while providing step-down conversion ratios that take advantage of the higher voltage settings of Universal Serial Bus Type-C (USB-C) power delivery (PD). Moreover, moving the inductor to the input allows the parasitic inductance of a USB cable to be utilized in place of a discrete inductor, that is, a smart-cable architecture, eliminating the need for on-board magnetics and reducing on-board power dissipation. The converter is implemented in 7.37 mm2 of a 130-nm BCD process and provides two outputs with ranges of 3–4.2 V and 6–8.4 V from a 9V input. With a 1 $\mu \text{H}$ discrete inductor, the prototype achieves peak powers of 12.2W and 31.9W and peak efficiencies of 94.3% and 97.4% for each output, respectively. The prototype is also demonstrated in a smart-cable architecture to limit on-board dissipation to 630 mW while delivering 7.2W at the first output or 350mW while delivering 14.4W at the second output. Simultaneous data and power transfer and electromagnetic interference (EMI) tests are provided to support the feasibility of integration into a smart-cable architecture.

A New Control Technique for Improved Active-Neutral-Point-Clamped (I-ANPC) Multilevel Converters Using Logic-Equations Approach

The per-phase leg of an improved active-neutral-point-clamped (I-ANPC) multilevel converter is realized by the cascaded connection of the standard ANPC topology and the concatenated H-bridge modules consisting of the flying-capacitors (FCs). This article proposes an innovative approach for the active control of the I-ANPC inverters. The introduced methodology is developed on the basis of the logic-equations set for the active voltage balancing of the FCs within the H-bridge modules, and controlling the generated output voltage. It derives logic-variables employing the direction of the output current, and the deviation of the FCs’ voltages from their target operating levels in the H-bridge cells. These logic-variables are fed into a set of logic-equations derived for the control of the I-ANPC inverter. The regulation of the floating-capacitor voltages at their reference values along with synthesizing the required pulsewidth modulation voltage-level at the output having fast dynamics are the control objectives to achieve. The derived logic-equations and the proposed control method are explored and verified by the experimentally measured results obtained from the 5-kW prototype of a five-level converter.

A Novel Fault-Tolerant Control Method for Interleaved DC–DC Converters Under Switch Fault Condition

This article proposes an adaptive democratic current sharing control scheme for the interleaved dc–dc converters under faulty conditions. The proposed fault-tolerant control approach can achieve the desired output-voltage generation and equal current sharing among the remaining healthy modules as more and more modules fail. The main idea is to adaptively change the reference currents and the inner loop current regulator gains once the fault is detected in the modules. The proposed control scheme is compared to the democratic current sharing control scheme under the fault condition. The results show that it achieves improved output regulation and accurate current sharing among the modules. The presented fault-tolerant control method has been analyzed, tested, and validated for the interleaved boost converter.

Triangular Separation Distance Effects on Wave Electrical Energy Harvester Performance

Energy scavenging has become a topic of interest toward green and environmentally friendly. Vortex generated in the wake region behind a bluff body is potential to be harvested and transform the mechanical vortices into electrical energy. Therefore, the study of the fluid flow and piezoelectric material is highly potent and a promising research area. Thus, the vortex-induced vibration (VIV) energy harvesting of two bluff bodies in a tandem arrangement is investigated using the 3D simulation. There are four sets of bluff bodies with various distance ratio, x/D from 3 to 6, were analyzed in this simulation. The coupling analysis was analyzed using ANSYS Transient Structural and computational fluid dynamic Fluent module. The triangular width, to 100 mm and the fluid average flow velocity is 1.46 ms−1, which corresponds to Reynold number (Re) of 10k. Four types of analysis have, out; velocity vector, turbulence kinetic energy, piezoelectric tip deformation, and generated output voltage. The results show the bluff shape with spacing ratio 6 has better vortex shedding formation and turbulence kinetic energy formed on both upstream and downstream triangular bluff body. The tips mesh displacement for piezoelectric is highest at space ratio 6 with 7.0 x 10−5 essential, and after 10s the beam deflection is continuing at around 1 x 10−5 m. While the voltage generated is, at spacing ratio 6 with 0.2 v produced. The obtained results are essential to VIV analysis of the dual triangular cylinder with piezoelectric film, which is vital in energy scavenging knowledge.

New Family of Boost Switched-Capacitor Seven-Level Inverters (BSC7LI)

This paper proposes a new family of multilevel inverter topology that is able to generate seven voltage levels by utilizing one or two floating capacitors and 10 power switches. This novel boost switched-capacitor seven-level inverter possesses voltage boosting capability with an achievable maximum voltage level 1.5 times the input direct current (dc) voltage. The generation of higher output voltage does not incur high-voltage stress on any power switch in this topology, as the peak inverse voltages of all power switches do not exceed the input source voltage. In addition, capacitor voltage balancing is not essential since the floating capacitors are effectively balanced during the charging and discharging processes. Furthermore, the proposed topology eliminates the need for multiple isolated dc sources, and a single dc source is sufficient in both its single-phase and three-phase topologies. The operating principle and steady-state analysis of the proposed topology are elaborated. Experimental results from a single-phase prototype are then presented to verify the validity of the proposed topology.

P(VDF–TrFE) based spiral thermo-magneto-electric generators for harvesting low grade thermal energy

Low-grade thermal energy harvesting remains a challenge because of the low Carnot efficiency. Among various thermal energy harvesting mechanisms available for capturing low-grade heat (hot-side temperature less than 100°C), thermomagnetic effect has been found to be the most promising. Developing a high power density thermo-magneto-electric generator (TMEG) requires developments at both materials as well engineering levels. In this study, we propose a novel P(VDF–TrFE) based spiral-shaped cantilever beam for TMEG. Numerical simulations were performed using COMSOL Multiphysics and it was found that spiral beam experiences higher stresses, and consequently exhibits higher voltage output, as compared to rectangular cantilever beam for the same magnitude of tip deflection. Experiments revealed that the spiral structure of dimension 2.5 mm x 2.5 mm generates output voltage of about 4.0 mV, when oscillation displacement is 0.5 mm and oscillation frequency is 1 Hz. The output voltage increases with increase in tip deflection as well as oscillation frequency and a peak voltage of 25 mV is obtained at oscillation frequency of 10 Hz.

Performance Analysis of Three-Phase Controlled Rectifier in various Switching Angles

This paper discusses the performance analysis the characteristics of three-phase controlled rectifier parameters based on various switching angles. The phase delay method with various switching angles is employed to generate output voltage. Analysis of calculations is engaged to determine the various desired parameters. Voltage and current waveforms both input and output side are considered. The analysis are verified by simultion. The results show that the calculation results and simulation results are the similarly.

Simulation model of dynamic voltage stabilizer for autonomous power supply systems

The article presents a simulation model of a dynamic voltage stabilizer utilized in autonomous power supply systems. The proposed simulation model allows developers to test at the design stage the parameters of a real device for compliance with the requirements of the Interstate standards. Models of individual units of the dynamic voltage stabilizer and their key elements modes of operation are described. Graphs of control pulses and a pulse-width modulation are presented. The device implemented based on the proposed simulation model stabilizes the output voltage of an autonomous generator and corrects its shape bringing it closer to the ideal sine wave with the amplitude and frequency parameters of 2202V and 50kHz, respectively.

Three Phase Five Level T-Type Multi Level Inverter using Hybrid Sources

This paper presents a 5 level T-type multilevel inverter, to improve the performance of the hybrid system and then improved voltage is injected into the grid. Two three level inverter with common emitter and common collector configurations are combined to obtain a five level inverter. PV and wind energy is used as a source of energy to the five level T-type MLI. It has advantages such as low switching losses, lesser THD, less filter requirement and superior output quality when compared to 3-level T-type MLI. PWM technique is employed to generate output voltage. The Simulation is done using MATLAB Simulink.

Effect of annealing treatment on PVDF nanofibers for mechanical energy harvesting applications

Piezoelectric nanofibrous films with superior flexibility have attracted the emerging applications including sensors and actuators, piezoelectric nanogenerators (PNG) and energy storage devices. Herein, polyvinylidene fluoride (PVDF) piezoelectric nanofibrous film have been made by the electrospinning technique and been exposed to annealing as a post processing treatment at 40, 70, 100 and 130 °C for 4 h in air-flow oven. Four kinds of samples annealed at various temperatures have been pointed out as PVDF40, PVDF70, PVDF100 and PVDF130, respectively. The crystalline phases and thermal responses of the annealed film have been examined with XRD, FTIR and DSC. Also, mechanical and electroactive investigations exhibited that annealing treatment has effectively enhanced the dielectric constant, piezoelectric coefficient and the polar β-phase. Moreover, the annealed PVDF film acts as an effective layer of the PNG with enhanced crystalline structure and polar β-phase fraction. When the film is annealed at 100 °C, the voltage output of the PNG can attain maximum microstrain of 1000 με. The developed PVDF100 nanofibrous film-based PNG can generate output voltage of 0.516 V and 0.505 V with a tensile and compressive microstrain measured using the microstrain indicator of 1000 με. It shows better results compared to PVDF40 of 0.221 V. The enhanced voltage output of the PNG is recognised to be the collaborative involvement of the electrospinning and annealing treatment which could improve the piezoelectric response of the annealed film. This work presents that the annealed PVDF nanofibrous film based highly compliant PNG could be a promising candidate for flexible self-powered electronic applications.

A Reactive Power-Voltage Control Strategy of an AC Microgrid Based on Adaptive Virtual Impedance

As an effective carrier of distributed generation, a microgrid is an effective way to ensure that distributed power can be reasonably utilized. However, due to the property of line impedance and other factors in a microgrid, reactive power supplied by distributed generation units cannot be shared rationally. To efficiently improve reactive power sharing, this paper proposes a reactive power-voltage control strategy based on adaptive virtual impedance. This method changes the voltage reference value by adding an adaptive term based on the traditional virtual impedance. Meanwhile, a voltage recovery mechanism was used to compensate the decline of distributed generation (DG) output voltage in the process. MATLAB/Simulink simulations and experimental results show that the proposed controller can effectively improve the steady state performance of the active and reactive power sharing. Finally, the feasibility and effectiveness of the proposed control strategy were verified.

A New Pulse Active Width Modulation for Multilevel Converters

This paper proposes a new pulse amplitude width modulation (PAWM) procedure for cascaded H-bridge multilevel inverters fed by dc voltage sources with unequal amplitudes. With proposed procedure, the generated output voltage is obtained modulating a sinusoidal reference signal at the desired fundamental frequency with equally spaced switching angles. It has been analytically demonstrated that, under these assumptions, all harmonics except those of order $n=2kl\pm 1$ , $k=1,2,\ldots$ are deleted from the output voltage waveform. After a detailed description of the method and a comparative analysis with others existing in the literature, its harmonics elimination capability has been experimentally verified with 5-, 7-, 9-, and 11-level cascaded H-bridge inverters, moreover, it has been mathematically demonstrated that it reduces total harmonic distortion below 5% with a 17-level inverter and it is capable of eliminating the first 49 harmonics considered by standards with a 27-level inverter.

Simulasi Pemodelan Sistem Eksitasi Statis pada Generator Sinkron terhadap Perubahan Beban

Excitation system is one of the most important parts of synchronous generators, where the system functions to provide dc power to the field generator coil. Iin this study, a static excitation system consisting of transformers and connected thyristors in bridge configuration has been implemented in synchronous machines that operate as 206,1 mva capacity generators, 16,5 kv using the help of matlab simulink r2017b software. By adjusting the load given to the generator, variations in excitation currents can affect the amount of output voltage generated by the generator so that it can increase and decrease the induced voltage. In full load conditions, namely p = 175 mw, q = 100 mvar, the results of the study show that when the simulation is run at alpha 0 °, it is known that the average value of dc voltage is 496,4 v, excitation current is 1057 a and voltage generator output has increased beyond its nominal voltage of 16,72 kv. in this case, to maintain the terminal voltage, the excitation current must be reduced by increasing the angle of shooting of the thyristor to an alpha angle of 45 °, so that the average dc voltage can be reduced to 479,3 v, as well as the excitation current to 985,9 a. the generator output voltage at the alpha 45 ° angle is obtained according to its nominal value of 1,.5 kv.

IoT Based Smart Solar Flower Water Pump System

The electric demand of the countries is increasing day by day and the available resources are quite insufficient to fulfill this demand. The reasons are that the conventional energy resources are diminishing and available with finite sources. Due to these reasons, the solar power is one of the promising alternatives that is easily available, pollution free and having higher operating life. The solar system also provides higher operating efficiency for the load, and the cost of the solar panel is minimum. To improve the switching technology used for the power conversion, we presented a smart flower system powered by photovoltaic panels that could supply standalone AC/DC load. In this system, solar panels produce a direct current, which can be converted into AC by the converter and used in home, industrial and agriculture applications. The output of the panels depends on the direction of sun's rays (solar energy), and the solar photovoltaic cell converts the solar energy into useful electrical energy. The aim of this paper is to develop the solar photovoltaic generation system based on a standard power electronics cell for micro industrial, commercial, home as well as agriculture applications. The proposed system is capable to provide protection from wind and rain, thereby the efficiency of the solar panels will increase. The generation of the electricity is more with trackers than stationary counterparts due to direct exposure to sun's rays. This increase can be as much as 25% depending upon the geographic location of the tracking system. The generated output voltage can be used for various purposes, and we used the store energy to run an agriculture water pump by using the internet of things (IoT). Citation:  Band, B. H., and Ingole, A. D. (2019). IoT Based Smart Solar Flower Water Pump System. Trends in Renewable Energy, 5, 229-236. DOI: 10.17737/tre.2019.5.3.0098

Magnetic Resonance Examinations of Patients With Implanted Active Devices. A Low-Cost Approach in Slew Rate Evaluation.

Time-varying magnetic field gradients involved in magnetic resonance examinations can damage implanted electronic systems. The quantity related to this side effect is the gradient slew rate, which is usually not directly available on magnetic resonance console. The present study proposes a low-cost approach in slew rate assessment, which is useful in risks versus benefits evaluation as well as in sequences optimization. The experimental method is based on an analog circuit, which senses the output voltage of the scanner waveform generator. This allows taking easy and reliable slew rate measurements, even during clinical examinations on patients. Whereas previous studies required managing a considerable amount of data, the present work addresses only the maximal slew rate of any clinical sequence. Experimental results show that the smooth gradient mode, selectable on the two scanners examined, is very effective in patient safety improvement. In particular, it reduces slew rate values in the range from 52.4 up to 132.4 T m-1 s-1 , i.e. far below the interval 216-346 T m-1 s-1 , indicated as slew rate tolerance limit of modern implanted electronic devices. Bioelectromagnetics. 2019;40:512-521. © 2019 Bioelectromagnetics Society.

Nonlinear observer based PI sliding surface of adaptive sliding mode control for boost converter in PV system

In photovoltaic system, solar energy is not able to be directly utilized to the grid. This is because the the generated output voltage from solar array are fluctuating depends on the environmental condition, such as the intensity of solar irradiance and temperature. Any changes from those variables will affect the generated output voltage. Boost converter is one type of power converter that is able to regulate the output voltage of solar array to dc grid. However, the dynamics of boost converter is nonlinear and non-minimum phase. Therefore, it requires an appropriate control method that can force the output voltage follows the desired reference voltage, by considering the fluctuation of environmental conditions and loads. To reduce the number of sensors and cost investment, nonlinear observer technique is employed to estimate the input voltage and load variations. By considering this problem, this paper is aimed at designing nonlinear observer based on adaptive sliding mode control with PI sliding surface for boost converter. The stability of proposed system is investigated through analytical and simulation proof. As comparison with PID controller, the performance of proposed system has produced Integral Absolute Error (IAE) about 7 times smaller than PID controller when it is tested under various conditions.

Nonlinear observer based PI sliding surface of adaptive sliding mode control for boost converter in PV system

In photovoltaic system, solar energy is not able to be directly utilized to the grid. This is because the the generated output voltage from solar array are fluctuating depends on the environmental condition, such as the intensity of solar irradiance and temperature. Any changes from those variables will affect the generated output voltage. Boost converter is one type of power converter that is able to regulate the output voltage of solar array to dc grid. However, the dynamics of boost converter is nonlinear and non-minimum phase. Therefore, it requires an appropriate control method that can force the output voltage follows the desired reference voltage, by considering the fluctuation of environmental conditions and loads. To reduce the number of sensors and cost investment, nonlinear observer technique is employed to estimate the input voltage and load variations. By considering this problem, this paper is aimed at designing nonlinear observer based on adaptive sliding mode control with PI sliding surface for boost converter. The stability of proposed system is investigated through analytical and simulation proof. As comparison with PID controller, the performance of proposed system has produced Integral Absolute Error (IAE) about 7 times smaller than PID controller when it is tested under various conditions.

Structure and the space vector modulation for a medium‐voltage power‐electronic‐transformer based on two seven‐level cascade H‐bridge inverters

This study presents the structure and the space vector pulse-width modulation (SVPWM) for power electronic transformer (PET) based on two seven-level cascade H-bridge (CHB) inverters. The DC links of CHB inverters are coupled with nine dual-active bridge (DAB) converters with medium-frequency transformers. The DC-link voltages are equalised with two methods - through the control of DAB voltages and through the modulation strategy applied to both CHB inverters. In the proposed SVPWM, the influence of vector sequences on predicted DC-link voltages is analysed, and the optimum vector sequence is selected to equalise them. Regardless of this, the proposed SVPWM strategy enables the proper generation of output voltage vector also in the case of DC-link voltage imbalance - the calculation of the space-vector area takes into consideration the inequality of the DC-link voltages and its influence on the lengths and positions of active vectors. To simplify the modulation algorithm, the multilevel CHB inverter is considered as a set of three-level inverters connected in series. Each of them is controlled using the same SVPWM algorithm. The proposed modulation method reuses the H-bridges with zero duty cycles determined in the initial stages of the output voltage generation process. This enables the optimal management of the DC-link voltage distribution. The experimental research was carried out on a 600 kW/3.3 kV PET. The results are presented in this study.