Peak Value Of Voltage Research Articles

Modeling and analysis of a rotational piezoelectric energy harvester with limiters

A rotational piezoelectric energy harvester has the ability to convert rotation mechanical energy into electric power. The piezoelectric harvester with cantilever based on gravity excitation has received great attention. Given that gravity excitation is greater than conventional vibration excitation, and large mass are often used in low-frequency applications, large amplitudes pose a significant threat to the life of a harvester. In this study, a rotational energy harvester with limiters is investigated to promote practical development. This study establishes a theoretical model verified by experiments. Results show that stiffness has little influence on the limiting effect. In the experimental conditions, the output after 2000 N/m is basically the same. The peak value of the output voltage is linearly proportional to the space. Given that an impact excitation is generated in the collision, the limiter widens the frequency band of the output in the upsweep.

On Lightning-Induced Voltages in Overhead Lines Over High-Resistivity Ground

This paper presents an improved analytical expression for the calculation of the lightning horizontal electric field considering high values of ground resistivity, which is validated by comparing its results with published results obtained with other methods. The expression is used to calculate lightning-induced voltages in overhead power distribution lines and its results showed that conducted currents injected into the ground by the lightning flash should be considered in the assessment of power line outages, whenever the ground resistivity is higher than 1000 Ω·m. The results also show that, for very high values of ground resistivity, the line length and the ground permittivity affect the lightning-induced voltage peak value, whereas the line height, the return stroke velocity, and the stroke current front-time have negligible effects.

(Invited) Ultralight Triboelectric Nanogenerators for Portable Self-Charging Power Unit and Self-Powered Sensing Platform

With rapid development of portable electronic devices and systems, mandatory requirements of portable, lightweight, and significantly sustainable power sources have attracted huge attention. Li-ion batteries or other energy storage devices are commonly used as a stable power supply for driving these electronic devices with small-scale energy consumption at the μW to mW level. Nevertheless, in modern personal electronics, batteries are usually the largest or heaviest component in the whole device, and moreover, the crucial problem of batteries is their limited lifetime and thus their need to be charged or replaced frequently. To conquer this problem, self-powered systems as integrated by an energy harvester and an energy storage device has been proposed and developed to simultaneously harvest and store ambient energy in the form of electricity, which opens potentials for sustainable and maintenance-free applications. Here, we report a ultralight cut-paper-based self-charging power unit (PC-SCPU) that is capable of simultaneously harvesting and storing energy from body movement by combining a paper-based triboelectric nanogenerator (TENG) and a supercapacitor (SC), respectively. Utilizing the paper as the substrate with an assembled cut-paper architecture, an ultralight rhombicshaped TENG is achieved with highly specific mass/volume charge output (82 nC g−1/75 nC cm−3) compared with the traditional acrylic-based TENG (5.7 nC g−1/5.8 nC cm−3), which can effectively charge the SC (∼1 mF) to ∼1 V in minutes. PC-SCPU is demonstrated as a sustainable power source for driving wearable and portable electronic devices such as a wireless remote control. To further enhance the output performance of TENG for extending the possible applications in portable electronic devices, we also report an ultrahigh output power of whirligig-inspired TENG (Wi-TENG) designed according to an antiqueue whirligig toy that is capable of converting low-frequency pulling motion into a high-frequency rotation. It shows that the rotor in the Wi-TENG achieves a maximum speed of 11,250 rpm. Ultrahigh charge transfer quantity of ~310 μC and output power of 40.18mW are obtained by per pulling of Wi-TENG. Moreover, a maximum short circuit current of 317 μA and a constant open-circuit voltage peak value of 153 V can be generated by the Wi-TENG, which can rapidly charge a commercial capacitance (100 μF) to ~14 V within 10 s. After power management, this Wi-TENG is successfully demonstrated as a portable sustainable power source for driving a commercial blood glucose meter.

Harvesting liquid stream energy from unsteady peristaltic flow induced pulsatile Flow-TENG (PF-TENG) using slipping polymeric surface inside elastomeric tubing

Flow in small size tubing or channels in multidisciplinary field such as Chemistry, medical and lab on chip sensors can be a potential candidate for energy scavenging. Recently, energy harvesting techniques have been developed utilizing the steady flow under induced pressure gradient in lab on chip device. Here, for the first-time harnessing energy from unsteady pulsatile water flow over hydrophobic polymeric surface attached in the inner wall of the elastic tubing that induces slip boundary and causes electrostatic potential difference in the electrical double layer of the solid-liquid interface is described. This work demonstrates peristaltic flow driven triboelectric nano-generator based on the flow contact electrification between the hydrophobic micro porous PVDF (mpPVDF) membrane and water stream flowing through elastic silicon tubing. The efficiency of the PF-TENG as energy harvester was evaluated using deionized water (PF.DIw-TENG), tap water (PF.Tw-TENG). The mechanistic approach is discussed for the generation of alternating current based on the relation between the hydrodynamics of pipe flow and adsorbed ions at the Electrical Double Layer (EDL). The generated voltage and short-circuit currents (Isc) are superior in PF.Tw-TENG, in particular, the maximum peak to peak values of voltage and Isc are 20.93 V and 1.67 μA, respectively, over PF.DIw-TENG. The PF.Tw-TENG shows greater efficiency over PF.DIw-TENG due to the presence of dissolved free mobile ions which can enhance the power output. Moreover, we verify the possibility of the PF-TENG as self-powered average volumetric flow rate sensor. The developed PF.TENG can be potentially applied for fluid dynamic monitoring of peristaltic flow involved in pharmaceuticals and food industries.

Control strategies for non‐sinusoidal multiphase PMSM drives in faulty modes under constraints on copper losses and peak phase voltage

In the context of future permanent magnet synchronous machines (PMSMs) with a high number of phases (>7) in integrated drives, this study proposes several control strategies when multiphase PMSMs with non-sinusoidal back electromotive forces (back-EMFs) operate in healthy and open-circuit faults. In all operation modes, the considered constraint on current is related to the maximum root mean square current allowable in one phase of the machine. The constraint on voltage limits the maximum peak value of the phase voltage determined by the DC-bus voltage of the converter. When one or two phases are open-circuited, to maximise torque and respect the constraints, new current references obtained by several proposed methods in rotating and natural frames are imposed to the machine. Owing to the non-sinusoidal waveform of back-EMFs and the considered constraints, numerical computations based on analytical formulations are required to obtain maximal torque-speed characteristics, including the flux-weakening operation. The usefulness of the proposed strategies is verified by numerical and experimental results.

Phase voltage distortion of IPM and SPM machines with distributed windings in field weakening region

This study investigates the field-weakening capability of interior permanent magnet (IPM) and surface-mounted permanent magnet (SPM) machines with distributed windings by considering phase voltage distortion in field-weakening region. For analysis and comparison, the Nissan Leaf vehicle traction machine is studied as a reference benchmark machine and then a comparable SPM machine is designed within the main constraints of the benchmark machine. A finite element analysis model of the benchmark machine is developed and validated by published experimental measurement. Sinusoidal phase current is desired to enhance machine torque performance and power electronic converters employing vector control method are commonly used for traction machine supply. However, the machine terminal phase voltage distortion may introduce additional difficulties for machine control. Therefore, firstly, phase voltage distortions of IPM and SPM machines with distributed windings are compared and the mechanisms are discussed. Due to the voltage distortion, the peak value of phase voltage may be higher than the fundamental one. Therefore, the influences of IPM and SPM topologies on machine traction characteristics are investigated. The study indicates that SPM machines with distributed windings can be designed to achieve comparable torque and power performance and better field-weakening capability compared to IPM machines.

A Novel Topology of a Liquid Metal Current Limiter for MVDC Network Applications

A liquid metal current limiter (LMCL) utilizing a fast switch and a parallel connecting path and consisting of several serial current limiting elements (CLEs) has the potential for use in a dc system. The current commutation ability is vital to the reaction time and the current limiting efficiency of this LMCL. In this paper, the characteristics of a natural current commutation driven by the arc voltage between contacts are first revealed; this method can only be applied in a low-voltage system. To fulfill the demands of a medium-voltage direct current system, an innovative LMCL topology is recommended due to the forced current commutation driven by an auxiliary magnetic induction module. A specially designed structure of magnetic coupling coils with a high coupling coefficient is proposed to improve the current commutation ability. The forced current commutation characteristic is analyzed via simulation and verified experimentally. Furthermore, the arc V–I characteristics of CLEs are deeply discussed to guide the selection of serial quantity of the CLE. Finally, a prototype for the complete LMCL is designed, assembled, and tested in the laboratory. The current limiting coefficient of the LMCL is less than 0.464, the peak value of arc voltage is approximately 6.3 kV, and the current limiting reaction time is 1.53 ms.

Characteristics of the dielectric barrier corona discharges

In this paper, the electrical characteristics of both the dielectric barrier corona discharge and the usual ac corona discharge have been studied in parallel with the ozone generation under the same operating conditions. Therefore, the corona discharges were formed inside two identical reactors in the form of a coaxial wire-to-cylinder with and without a dielectric barrier covering the inner surface of the cylinder. The two reactors have been fed by constant flow rates from the dry air and the oxygen gas independently at the atmospheric pressure and the room temperature, in parallel with applying a sinusoidal ac voltage to the electrodes of the reactors. The electric power consumed in forming the corona discharges and the waveform of the discharge current as well as the ozone concentration generated in the flowing gases through the reactors have been studied versus the peak of the ac voltage that was applied to the reactors. The current-voltage oscillograms showed that the sequence of the dielectric barrier corona discharge modes in both the dry air and the oxygen gas is the same as the sequence of the usual ac corona discharge modes in the same gases. With the increase of the peak value of the ac voltage applied to the dielectric barrier corona discharge reactor, the peak of the discharge current increases linearly while the value of the electric charge accumulated on the surface of the dielectric barrier increases in the form of a power function. The ozone concentration generated by the dielectric barrier corona discharges is approximately equal to the ozone concentration generated by the usual ac corona discharges in both the dry air and the oxygen gas under the same operating conditions.

A novel energizing strategy for a grid-connected modular multilevel converter operating as static synchronous compensator

This paper proposes a novel energizing strategy for a three-phase modular multilevel converter connected to the electric network as static synchronous compensator. The energizing system is comprised of two thyristors and its controller. A comprehensive mathematical model is developed for each energizing stage. Based on the models, a control law is designed in order to compute the thyristors firing angle. This is performed in such a way that the maximum value of the energizing current drained from the grid is limited. First, during the positive half-cycle of the mains voltage, the current flows through two arms of the modular converter charging its DC capacitors. In the following half-cycles, the pre-charged capacitors transfer part of their stored energy to the other arms capacitors. The process is repeated until the total DC voltage of the modular converter reaches the grid voltage peak value. Digital simulation results are presented to validate the proposed methodology.

Experimental research on piezoelectric ceramics activating micro‐sized thermochemical battery

AbstractTo verify feasibility of piezoelectric ceramic activating micro‐sized thermochemical batteries, it is very necessary to disclose shock pressure and electric output performances of piezoelectric ceramic. In order to simulate piezoelectric ceramic activating micro‐sized thermochemical batteries in the bore, shock pressure, and electronic output testing systems for piezoelectric ceramic have been established. And the piezoelectric ceramics composite structural targets are impacted using one‐stage light gas gun to load projectile, which is used to simulate the overload of the projectile with piezoelectric ceramics during projectile launching process, and combining with the experimental tests of a military 3# electric fuse head as a firing component in series. In experiments, the composite structural targets (front steel substrate‐piezoelectric ceramic‐rear steel substrate) are vertically impacted by the cylindrical 2A12 aluminum projectiles. The change rules of shock pressure, output voltage, and current peak values for piezoelectric ceramics are obtained at the different experimental parameters, and the firing conditions of piezoelectric ceramic igniting the military 3# electric fuse heads and ignition paper are presented.

Tunable Assembly of Superfine Single-Walled Carbon Nanotube Fibers

We have developed a method of spinning superfine single-walled carbon nanotube (SWNT) fibers to facilitate their assembly in 2D counter microelectrode array via alternating current (AC) dielectrophoresis (DEP) by using clean, combination of ionic surfactants, and stable SWNT aqueous high-quality solutions. Our method can attract metallic SWNTs (M_SWNTs) toward a counter microelectrode array, resulting in an opposite movement of semiconducting SWNTs (S_SWNTs) and leaving S_SWNTs in the suspension by taking advantages of the differences in the relative dielectric constants of M_SWNTs and S_SWNTs with respect to the suspension and substrate-bent AC DEP structure. Our method can also control the stretching or relaxed extent and diameters of the suspended SWNT fibers by tuning the bending degree of a flexible substrate, AC frequency, peak value of AC voltage, and time. The effectiveness of the method is proven by the electrical measurement result‚ scanning electron microscopy image, atomic force microscope image and Raman spectroscopy on test samples.

Organic matter and ammonia removal by a novel integrated process of constructed wetland and microbial fuel cells.

A novel approach, combining a microbial fuel cell (MFC) with an integrated vertical flow constructed wetland (IVCW), was developed, and its ability to simultaneously produce electrical energy while treating swine wastewater was verified. The system combined the singular water flow path of a traditional vertical flow constructed wetland (upflow and downflow)-microbial fuel cell (CW-MFC), which demonstrates better characteristics in the aerobic, anoxic, and anaerobic regions. It not only enhanced the anti-pollution load ability and the organic compound removal effect, but also improved the gradient difference in the redox potential of the system. The results showed that the structure and substrate distribution in the device could both improve swine wastewater treatment and increase bioelectricity generation capabilities. The average chemical oxygen demand (COD) and ammonia nitrogen (NH4+–N) removal efficiencies were as high as 79.65% and 77.5%, respectively. Long-term and stable bioelectricity generation was achieved under continuous flow conditions. The peak values of the output voltage and power density were 713 mV and 456 mW m−3. The activated carbon layer at the bottom of this system provided a larger surface for the growth of microbes. It showed significant promotion of the relative abundance of electrochemically active bacteria, which might result in the increase of bioelectricity generation in integrated vertical flow constructed wetland-microbial fuel cells (IVCW-MFCs). The electrochemically active bacteria, Geobacter and Desulfuromonas, were detected in the anodic biofilm by high-throughput sequencing analysis.

Pyroelectric performance of (Ba0.825+xCa0.175-x)(Ti1-xSnx)O3 lead free ceramics

The pyroelectric properties of (Ba0.825+xCa0.175-x)(Ti1-xSnx)O3 ceramics with x = 0.0625, 0.0875 and 0.100 were investigated. Samples were fabricated using solid state reaction route and were exposed to IR lamp periodically to recorded open circuit voltage. Peak value of open circuit voltage was 0.8 V, 0.70 V and 0.53 V for x = 0.0625, 0.0875 and 0.1 samples, respectively. P–E loops were recorded for all the compositions under study. Further pyroelectric coefficient was estimated using P–E loops data. The values of pyroelectric coefficient estimated as 5.70 × 10−4C/m2 K, 5.5 × 10−4C/m2 K and 5 × 10−4C/m2 K for x = 0.0625,0.0875 and 0.1 samples.

Non‐touch detection of rhodamine B concentration in distilled water using fiber coupler based on displacement sensor

AbstractNon‐touch detection of rhodamine B concentration in distilled water using fiber coupler and concave mirror (CM) successfully demonstrated. Based on displacement sensor, the concentration of rhodamine B is detected through the peak voltage value which is resulted from the displacement profile. Using the He‐Ne (543 nm) laser as the source, the fiber coupler as the sensor probe and CM with the curvature radius of 12 mm as the reflector as well as the sample container, the rhodamine B concentration can be detected in the range 0‐20 ppm and the resolution of 0.26 ppm.

Integrated DC–DC Converter Based Grid-Connected Transformerless Photovoltaic Inverter With Extended Input Voltage Range

Owing to low cost, small size, and low weight, transformerless inverters became prominent in single-phase grid connected photovoltaic (PV) systems. Key issues pertaining to these inverters include suppression of common mode (CM) leakage current and improvement of conversion efficiency. Achieving higher efficiency in single-phase grid-connected photovoltaic systems depends on the number of stages involved in feeding power to the grid, predominantly, if the PV array voltage is less than the peak value of the grid voltage. In this paper, an integrated dc–dc converter based grid-connected transformerless PV inverter is proposed which is aimed at maintaining high efficiency, even if the PV array voltage falls below the peak value of grid voltage (efficient operation at an extended input voltage range). A modulation strategy is discussed in order to minimize the flow of CM leakage current. Further, the efficiencies of certain transformerless inverter topologies are analyzed and compared with that of the proposed topology. Detailed simulation studies are carried out in MATLAB/Simulink environment to verify the analysis. Experimental results for a scaled down laboratory prototype are included as a proof-of-concept to validate the claims.

An Active Partial Switching Method in Tertiary Loop for a High-Efficiency Predictive Current-Mode Control PFC Converter

This paper proposes a novel active partial switching method for a boost power factor correction (PFC) converter, based on the predictive current mode control to achieve both current shaping capability and high power conversion efficiency. This method consists of a controller that maintains a switching stop angle near the peak voltage of the input voltage by means of output voltage control, and an adaptive current shaper that adjusts the switching stop period near the zero voltage of the input voltage based upon the load condition. The proposed method shows good PFC performance and high efficiency even under various disturbances such as input voltage and load fluctuations. Moreover, it has the advantage that it is possible to achieve high efficiency even under conditions of output voltage exceeding the peak value of the input voltage. For sequential explanation, this paper illustrates the design of the controller based on the frequency-domain response and provides theoretical analysis of the proposed method. Finally, to verify the effectiveness of the proposed method, experimental results are presented based upon a 2.4 kW boost PFC converter prototype.

Asymmetric Rotor Design for Synchronous Motor to Reduce Harmonics of Induced Voltage under Load Condition

The harmonics of the induced voltage under load conditions cause the deterioration of the motor performance. It occurs when the peak value of the demand voltage exceeds the DC link voltage. In this paper, thus, to reduce the induced voltage harmonics under load conditions, an asymmetric rotor design method using the advanced inverse cosine function (AICF) is proposed. Using this method, the rotor shape is determined by considering the armature reaction under certain load condition. As a result, an improved concentrated flux synchronous motor (CFSM) achieving the required performance is designed. Lastly, the induced voltages waveforms of the proposed motors under the load conditions are compared through finite-element analysis (FEA) as well as experiments.

Single-Stage Converter Based on the Charge-Pump and Valley-Fill Concepts to Drive Power LEDs

This paper proposes a nonisolated single-stage electronic system for driving power LEDs using the charge-pump and valley-fill concepts. Both concepts are related to the topological configuration based on the integration of a full-wave rectifier at the input stage with a half-bridge inverter at the output, characterizing a single-stage system. The charge-pump configuration is used to reduce the LEDs’ current ripple. The valley fill is employed to limit the dc bus voltage at levels below the peak value of the input voltage but maintaining a high-power factor operation. Therefore, it is possible to use bus capacitors with reduced voltage ratings. The operating principle of the proposed converter, which includes three operating modes in steady state, is presented and analyzed. The design methodology and the experimental results are also presented so that the operational characteristics of the proposed system can be verified. A 47-W, 220-Vac input, 67 kHz, 93.5% peak-efficiency prototype is built and tested to validate the carried out analyses.

Lead Iodide Nanosheets For Piezoelectric Energy Conversion And Strain Sensing

Abstract Flexible piezoelectric devices are attractive for energy conversion and strain sensing applications, including in the area of wearable electronics and self-powered sensors. Here, we report a piezoelectric nanogenerator/strain sensor based on lead (II) iodide (PbI2) nanosheets with the shape of two-dimensional (2D) structures, of which the piezoelectricity is not affected by the number of layers. A typical 2D piezoelectric device fabricated with 3 layers PbI2 nanosheets has recorded peak values of open-circuit voltage, short-circuit current and loading power as 29.4 mV, 20 pA, and 0.12 pW, respectively, and also possess good charging and integration capabilities. Moreover, these devices can be applied as self-powered strain sensors, with high sensitivity and excellent stability. As such, this study provides new knowledge and strategy for flexible energy harvesting or strain sensing devices based on 2D structures.

A Wrinkled PEDOT:PSS Film Based Stretchable and Transparent Triboelectric Nanogenerator for Wearable Energy Harvesters and Active Motion Sensors

AbstractThe functionalized conductive polymer is a promising choice for flexible triboelectric nanogenerators (TENGs) for harvesting human motion energy still poses challenges. In this work, a transparent and stretchable wrinkled poly(3,4‐ethylenedioxythiophene):poly(4‐styrenesulfonate) (PEDOT:PSS) electrode based TENG (WP‐TENG) is fabricated. The optimum conductivity and transparency of PEDOT:PSS electrode can reach 0.14 kΩ □−1 and 90%, respectively, with maximum strain of ≈100%. Operating in single‐electrode mode at 2.5 Hz, the WP‐TENG with an area of 6 × 3 cm2 produces an open‐circuit voltage of 180 V, short‐circuit current of 22.6 µA, and average power density of 4.06 mW m−2. It can be worn on the wrist to harvest hand tapping energy and charge the capacitor to 2 V in ≈3.5 min, and then drive an electronic watch. Furthermore, the WP‐TENG as the human motion monitoring sensor could inspect the bending angle of the elbow and joint by analyzing the peak value of voltage and monitor the motion frequency by counting the peak number. The triboelectric mechanism also enables the WP‐TENG to realize high‐performance active tactile sensing. The assembled 3 pixel × 3 pixel tactile sensor array is fabricated for mapping the touch location or recording the shape of object contacted with the sensor array.