Voltage Generator Research Articles

A Quadrature Oscillator with a Frequency-Tuned Distributed RC Network Analysis

This paper introduces an innovative two-stage distributed RC oscillator design, enhancing the noise performance and frequency stability for compact electronic devices. This work significantly reduces the comparator noise and improves system reliability by implementing a novel approach to increase the signal transition slope, coupled with optimized resistor and capacitor configurations. The study employs a quadrature oscillator topology and a precise reference voltage generation method, effectively addressing the challenges of mismatch and noise performance. A 469.2 kHz quadrature oscillator with two-stage distributed RC is implemented with a 0.18 μm CMOS process, achieving a FoM of −160 dBc/Hz at 100 Hz with a stable −20 dB roll-off in the phase noise and an Allan deviation floor of less than 0.7 ppm.

Ionic Thermoelectric Generators in Vertical and Planar Topologies Based on Fluorinated Polymer Hybrid Materials with Ionic Liquids.

Ionic thermoelectrics (TEs), in which voltage generation is based on ion migration, are suitable for applications based on their low cost, high flexibility, high ionic conductivity, and wide range of Seebeck coefficients. This work reports on the development of ionic TE materials based on the poly(vinylidene fluoride-trifluoroethylene), Poly(VDF-co-TrFE), as host polymer blended with different contents of the ionic liquid, IL, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [EMIM][TFSI]. The morphology, physico-chemical, thermal, mechanical, and electrical properties of the samples are evaluated together with the TE response. It is demonstrated that the IL acts as a nucleating agent for polymer crystallization. The mechanical properties and ionic conductivity values are dependent on the IL content. A high room temperature ionic conductivity of 0.008 S cm-1 is obtained for the sample with 60 wt% of [EMIM][TFSI] IL. The TE properties depend on both IL content and device topology-vertical or planar-the largest generated voltage range being obtained for the planar topology and the sample with 10 wt% of IL content, characterized by a Seebeck coefficient of 1.2 mV K-1. Based on the obtained maximum power density of 4.9 µW m-2, these materials are suitable for a new generation of TE devices.

Power Compatibility of Induction Motors in Industrial Grids Containing Synchronous Generators

Starting an induction motor causes voltage sag in the industrial grid that may disturb the operation of grid equipment. Direct-on-line starting is the simplest and most cost-effective method for starting induction motors, but also the most problematic. Large industries often use internal power plants with synchronous generators and starting powerful motors may impact the generator operations. The synchronous generators could be operated with the automatic or manual mode of voltage control. As the operation experience proves, the generator voltage control mode has a significant impact on the transient behaviours in the industrial power grid when starting a large induction motor. This article presents a case study of the synchronous generator tripping within a true medium-voltage industrial grid during the direct-on-line starting of a large induction motor driving the feed water pump. An analysis of the generator protection logs after the tripping showed that the synchronous generator was controlled in manual mode and its protection relay settings were exceeded. The transients initiated by induction motor starts were studied for possible configurations and operating conditions of the grid using a model developed on the Matlab/Simulink Software platform. The simulations have shown that concern about starting large motors in industrial grids containing internal synchronous generators needs to be solved considering the grid configurations and the coordination of generator protection and control devices.

Experimental investigation of the external load effect on thermoelectric generator discharge time in a low power energy harvesting system

Thermoelectric generator systems are often evaluated and studied in open circuit and close circuit modes. In the open circuit case, minimum heat flux passes across the thermoelectric module and the module does not have any thermal losses. Moreover, in the close circuit system, the external consumer is connected to the module and higher heat is pumped from its hot side to cold side. Hence, investigating the effect of external load resistance as the consumer connected to the module on its response is a significant issue in thermoelectric systems. In this study, to evaluate the effect of various consumers (4, 8, 10, 15, 20 and 30 Ω) over the module on discharge time, output voltage and temperature on both sides of the module, thermoelectric systems lacking and containing phase change material as the useful means for energy storage and thermal management of thermoelectric system were designed and exposed to constant heat loads. Results of this study show that the power consumption of the internal resistance of the module (connected to the consumer) led to an increase in the temperature of both sides of the module compared to open circuit systems. Therefore, the thermal balance and temperature distribution over the module changes and more affected. The maximum output power and discharge time were obtained at the external resistance of 4 Ω (close to the average internal resistance of the module) in the studied systems. The phase change material prevented excessive temperature on the hot side during the charging process and provided proper thermal management to enhance voltage generation and discharge time. The thermoelectric generator is an effective technology in starting consumers with low resistance, such as light bulbs and remote controls.

Tribovoltaic Effect: Origin, Interface, Characteristic, Mechanism & Application.

Tribovoltaic effect is a phenomenon of the generation of direct voltage and current by the mechanical friction on semiconductor interface, which exhibits a brand-new energy conversion mechanism by the coupling of semiconductor and triboelectrification. Here, the origin, interfaces, characteristics, mechanism, coupling effect and application of the tribovoltaic effect is summarized and reviewed. The tribovoltaic effect is first proposed in 2019, which has developed in various forms tribovoltaic nanogenerator (TVNG) including metal-semiconductor, metal-insulator-semiconductor, semiconductor-semiconductor, liquid-solid and flexible interfaces. Compared with triboelectric nanogenerator, the TVNG has the characteristics of direct-current, high current density (mA-Acm-2) and low impedance (Ω-kΩ). The two mainstream views on the tribovoltaic generation mechanism, one dominated by built-in electric fields and the other dominated by interface electric fields, have been elaborated and summarized in detail. The tribo-photovoltaic effect and tribo-thermoelectric effect are also discovered and introduced because they can easily interact with other multi-physical field effects. The TVNGs are suitable for making energy harvesting and self-powered sensing devices for micro-nano energy applications. This paper not only revisit the development of the tribovoltaic effect, but also makes prospects for mechanism research, device fabrication and integrated application, which can accelerate the evolution of smart wearable electronics and intelligent industrial components.

EXPERIMENTAL DEMONSTRATION OF ELECTRICAL POWER GENERATION USING STATIONARY EXERCISE BICYCLE COUPLED WITH WIND TURBINE REGULATOR

The small power generation using exercise bicycle is one of the current areas patronized by researchers. This is due to the two major benefits obtainable from the exercise machine, the benefit of exercising one’s body and the utilization of electrical power generated. Wind turbine regulator is specifically designed to regulate the output voltage of a wind turbine generator, which is characterized by varying speed and hence varying output power. The exercise bicycle driven alternator has a similarity with wind turbine generator in terms of variable speed, especially when ridden by different personalities. This paper demonstrates how small power can be generated using exercise bicycle. Further, the paper analyzes the performance of the by regulating its output using small wind turbine regulator. The result shows that, a regulated output within the range of 12V is obtained for all the tested loads, which makes the system more compatible with all types of 12V DC loads. Also the excitation voltage of the machine is improved from 4.5V (1.22A) using the diodes rectifier to 2.5V (0.81A) when the wind turbine regulator is used. With the improved power generation in this work the exercise bicycle will be a better alternative source for small power generation which can be used in DC lightings, DC fans, charging batteries and laboratory experiments.

An evaluation of 2013 privatization on Benin Electricity Distribution technical and workforce performance

Purpose This study aims to investigate the impact of the 2013 privatization of Nigeria’s energy sector on the technical performance of the Benin Electricity Distribution Company (BEDC) and its workforce. Design/methodology/approach This study used a questionnaire-based approach, and 196 participants were randomly selected. Analytical tools included standard deviation, Spearman rank correlation and regression analysis. Findings Before privatization, the energy sector, managed by the power holding company of Nigeria, suffered from inefficiencies in fault detection, response and billing. However, privatization improved resource utilization, replaced outdated transformers and increased operational efficiency. However, in spite of these improvements, BEDC faces challenges, including unstable voltage generation and inadequate staff welfare. This study also highlighted a lack of experience among the trained workforce in emerging electricity technologies such as the smart grid. Research limitations/implications This study’s focus on BEDC may limit its generalizability to other energy companies. It does not delve into energy sector privatization’s broader economic and policy implications. Practical implications The positive outcomes of privatization, such as improved resource utilization and infrastructure investment, emphasize the potential benefits of private ownership and management. However, voltage generation stability and staff welfare challenges call for targeted interventions. Recommendations include investing in voltage generation enhancement, smart grid infrastructure and implementing measures to enhance employee well-being through benefit plans. Social implications Energy sector enhancements hold positive social implications, uplifting living standards and bolstering electricity access for households and businesses. Originality/value This study contributes unique insights into privatization’s effects on BEDC, offering perspectives on preprivatization challenges and advancements. Practical recommendations aid BEDC and policymakers in boosting electricity distribution firms’ performance within the privatization context.

Realizing stretchable energy harvesting film through stretch-buckling conversion of wavy base

Abstract In this study, we designed and fabricated a stretchable energy harvesting device. This device operates by inducing buckling in the Lead Zirconate Titanate film through tension applied to the wavy base, resulting in voltage generation. Both simulations and experiments demonstrate that the aspect ratio between the pitch and curve radius of the symmetric wavy base influences the energy conversion efficiency of the piezoelectric device. An in-depth analysis revealed that increasing the resolution of the device leads to a proportional increase in energy conversion efficiency. This finding aligns with the mathematical modeling proposed in our study. Consequently, our study demonstrates the potential of miniaturized wavy piezoelectric devices in diverse applications, including soft robotics, wearable devices, and highly sensitive stretchable sensors. These devices hold promise for enhancing the efficiency of flexible devices by harnessing energy from mechanical movement.

Fabrication and Electrical Characterization of p/n PbSe Diodes

Lead selenide (PbSe) diodes were fabricated using a magnetron sputtering process system with a pulsed DC power supply and a 2-inch PbSe target with a purity of 5N. For p-type PbSe thin films, the process variable was the oxygen ratio in the mixed gas of argon and oxygen. The electrical characteristics of the thin films were observed after heat treatment. For the n-type PbSe, nickel (Ni) was used as a doping material. The deposition and doping were performed simultaneously using a co-sputtering method. During co-sputtering, the input power of the Ni sputter gun was adjusted as a process variable. Hall measurement experiments were performed to measure the doping concentration and resistivity of both the p-type and n-type PbSe semiconducting films. The maximum doping concentration was 2.33×10<sup>19</sup> cm<sup>-3</sup> for p-type PbSe and 7.55×10<sup>20</sup> cm<sup>-3</sup> for n-type PbSe thin films, respectively. The p-n junction IV curve showed that the lowest forward voltage generation point, V<sub>f</sub>, was 1.5 V and the reverse breakdown voltage was -4.3 V. In the photocurrent measurement, the photo sensitivities of the heat-treated samples were higher than that of the non-treated sample, and the maximum value was 5.148. Photo responsivity was also higher in the heat-treated samples. Its maximum was 0.7306 mA / W.

Analysis of Using Machine Learning Techniques for Estimating Solar Panel Performance in Edge Sensor Devices

The importance of the usage of renewable energy sources in powering wireless sensor nodes in IoT and sensor networks grows together with the increasing number of utilized sensor nodes. Considering the other types of renewable energy sources, solar power differs as the most suitable one and emerges as the major source for powering sensor nodes. Thus, the consideration of using sensor nodes and collected sensor data for estimating solar panel performances and therefore solar power potential can improve the efforts in this direction. This paper presents the methodology for implementing edge intelligence on wireless sensor nodes for solar panel output voltage estimation and forecasting. The methodology covers the usage of the Python Scikit-learn package and micromlgen library for the implementation of edge intelligence on Arduino clone-based sensor nodes, particularly the development boards based on the ESP8266 chips. Scikit-learn is used for analyzing the efficiency of various regressors on collected solar data. The micromlgen library is then used for implementing those regressors on Arduino and clone nodes. The prediction of solar panel voltage generation is based on a single-sensor reading—UV or BH1750 light sensor. The Random Forest and Decision Tree regressors are implemented on the ESP8266-based development board—Wemos D1 R2. The estimation accuracy of the RF model is an MSE of approximately 0.10, MAE of 0.07 for UV and 0.04 for BH1750, and an R2 of approximately 0.93 for both UV and BH1750 light sensors. The Decision Tree model has a lower accuracy with an MSE between 0.13 and 0.14, MAE of 0.07 for UV and 0.04 for BH1750, and R2 of 0.90 and 0.89 for the UV and BH1750 sensors, respectively. The methodology and its efficiency are presented and discussed in this paper.

A pulsed bipolar current-mode power supply with high power factor in a single stage for dielectric barrier discharge application

Purpose Dielectric barrier discharge (DBD) is widely used in the treatment of skin disease, surface modification of material and other fields of electronics. The purpose of this paper is to design a high-performance power supply with a compact structure for excimer lamps in electronics application. Design/methodology/approach To design a high-performance power supply with a compact structure remains a challenge for excimer lamps in electronics application, a current-source type power supply in a single stage with power factor correction (PFC) is proposed. It consists of an excitation voltage generation unit and a PFC unit. By planning the modes of the excitation voltage generation unit, a bipolar pulse excitation voltage with a high rising and falling rate is generated. And a high power factor (PF) on the AC side is achieved by the interaction of a non-controlled rectifier and two inductors. Findings The experimental results show that not only a high-frequency and high-voltage bipolar pulse excitation voltage with a high average rising and falling rate (7.51GV/s) is generated, but also a high PF (0.992) and a low total harmonic distortion (5.54%) is obtained. Besides, the soft-switching of all power switches is realized. Compared with the sinusoidal excitation power supply and the current-source power supply, the proposed power supply in this paper can take advantage of the potential of excimer lamps. Originality/value A new high-performance power supply with a compact structure for DBD type excimer lamps is proposed. The proposed power supply can work stably in a wide range of frequencies, and the smooth regulation of the discharge power of the excimer lamp can be achieved by changing the switching frequency. The ideal excitation can be generated, and the soft switching can be realized. These features make this power supply a key player in the outstanding performance of the DBD excimer lamps application.

A novel driver circuit of SiC MOSFET for suppressing crosstalk voltage in bridge circuit

Due to the presence of crosstalk voltage in the circuit, SiC MOSFET devices can be damaged or misled. Suppressing crosstalk voltage makes it an important step for the circuit to function properly. This article first delves into the causes of crosstalk voltage generation. The main research object is synchronous Buck converters, and the reasons for the crosstalk voltage of SiC MOSFETs are analyzed. Afterwards, a novel drive circuit was designed to suppress crosstalk voltage, and the working principle of this drive circuit was analyzed. Finally, simulation was conducted using LTspice software to study and analyze the simulation results, proving the feasibility of this novel drive circuit for suppressing crosstalk voltage, and demonstrating the advantages and disadvantages of this novel drive circuit for suppressing crosstalk voltage.

A Photovoltaic-based Novel Transformerless High Gain Converter for DC Microgrid Applications

Aim: A typical microgrid network sourced by renewable energy encounters a technical setback owing to the voltage imbalance across the source integration and load power dissemination. Transformers employed to stabilize the potential may deteriorate the network efficiency and increases the cost and size of the system as well. Introduction: Photovoltaic based transformerless high gain DC-DC converter (THG-DC) is proposed here to aid the microgrid infrastructure. Microgrid fuelled by renewable energy sources demands the high gain converter interface to boost low voltage generation. The proposed THG-DC is employed with four switched inductors and three active power switches (IGBT) which are brought together under dual leg configurations. Methods: The proposed topology offers dual-duty cycle modes of regulating the active switches to realize the desired output voltage. Moreover, it is reliable to drive the proposed THG-DC with lower values of duty cycles to achieve a higher gain. The voltage stress across the switches is minimized and the magnitude of inductor current ripples is quashed to an extent. The proposed THGDC is simple in architecture and easy to control in all three operating modes. Results: The operating characteristics and performance investigation of the novel converter during the continuous and discontinuous modes are elucidated briefly and the comparative analysis on switching stress, gain, and efficiency are executed to justify the standards of the proposed THGDC. Conclusions: Finally, the miniature prototype model is experimented with in the laboratory (0.3 kW) and the obtained results are in agreement with the theory. It is evident from the investigations that the proposed THG-DC shows its dominance over other converters on the voltage gain, switching stress, number of components, and overall efficiency.

Rapid Breakdown Time in Positive Impulse Voltages through Spectroscopy Analysis

The air discharge phenomenon, characterized by its rapid and transient nature, is inherently unpredictable, emphasizing the need for a comprehensive understanding of its physical interactions. Our experimental setup involved voltage generators producing both positive and negative impulse voltages (±100 kV, ±125 kV, and ±150 kV) at a 3.5 cm gap distance in a needle-to-plane geometry. This setup facilitated the study of individual spectral lines of impulse voltage discharges, with a specific emphasis on examining oxygen transitions through spectroscopy analysis. To explore the influence of photon emission on the breakdown rate, we examined the correlation between decay time, excitation temperature, and peak intensity during the transition from an upper state to a lower state. Our findings reveal that positive impulse voltage discharges more rapidly than negative impulse voltages. This heightened discharge rate is attributed to the higher peak intensities of O II at 313.421 and 241.162 nm, as well as O IV at 337.806 nm, observed in the excited state, as opposed to O I at 777.417 nm in the combination state. The inference drawn from the larger peak intensity suggests that energetic photon emission plays a pivotal role in initiating and expediting electron discharge in positive voltages.

Piezoionic Elastomers by Phase and Interface Engineering for High-Performance Energy-Harvesting Ionotronics.

Piezoionic materials play a pivotal role in energy-harvesting ionotronics. However, a persistent challenge lies in balancing the structural requirements for voltage generation, current conduction, and mechanical adaptability. The conventional approach of employing crystalline heterostructures for stress concentration and localized charge separation, while effective for voltage generation, often compromises the stretchability and long-range charge transport found in homogeneous quasisolid states. Herein, phase and interface engineering strategy is introduced to address this dilemma and a piezoionic elastomer is presented that seamlessly integrates ionic liquids and ionic plastic crystals, forming a finely tuned microphase-separated structure with an intermediate phase. This approach promotes charge separation via stress concentration among hard phases while leveraging the high ionic charge mobility in soft and intermediate phases. Impressively, the elastomer achieves an extraordinary piezoionic coefficient of about 6.0mV kPa-1, a more than threefold improvement over current hydrogels and ionogels. The resulting power density of 1.3 µW cm-3 sets a new benchmark, exceeding that of state-of-the-art piezoionic gels. Notably, this elastomer combines outstanding stretchability, remarkable toughness, and rapid self-healing capability, underscoring its potential for real-world applications. This work may represent a stride toward mechanically robust energy harvesting systems and provide insights into ionotronic systems for human-machine interaction.

ЗМЕНШЕННЯ ВПЛИВУ ВІДХИЛЕНЬ ПАРАМЕТРІВ ГЕНЕРАТОРІВ У ПРЕЦИЗІЙНИХ КВАДРАТУРНИХ МОСТАХ

The article is devoted to solving the problem of attestation of electric capacity standards at industrial frequency. The expediency of using a quadrature bridge of alternating current to determine the parameters of standards of electric capacity at industrial frequency by comparison with the parameters of standards of active resistance was noted. The advantage of using a bridge imbalance indicator with high input impedance is shown, which consists in the possibility of reducing the influence of higher harmonics of the supply voltages. An analysis of the well-known method of reducing of measurement errors caused by the deviation of the generator parameters from the calculated ones was carried out. It is shown that the known method does not provide sufficient compensation for the influence of these errors when the deviations of the generator parameters increase, as well as when the deviations of the bridge from the balance state increase. An iterative algorithm for calculating the measured deviation of the impedance ratio of the compared standards from the nominal value is proposed. Mathematical expressions for calculating the measured quantity are given. Calculations of the components of the measurement error for different values of generator voltage deviations were carried out. Calculations were performed for two variants of generator voltage variation implementation: multiplicative voltage amplitude variation and additive voltage phase variation. The developed iterative correction method allows to reduce the specified errors to the required levels in a small number of iteration steps - in the vast majority of cases, two steps are enough. The application of the method allows obtaining high metrological characteristics with rather large deviations of the voltage ratio of bridge generators, which makes it possible to reduce hardware costs when implementing quadrature alternating current bridges for comparing capacitance and active resistance standards. References 15, figure 1, table 1.

Flow Control Over a Finite Wall-Mounted Square Cylinder by Using Multiple Plasma Actuators

Abstract The present study aims to investigate the effectiveness of plasma actuators in controlling the flow around a finite wall-mounted square cylinder (FWMSC) with a longitudinal aspect ratio of 4. The test is conducted in a small-scale closed return-type wind tunnel. The Reynolds number of the experiments, Red, is 500 based on the width of the bluff body and the freestream velocity. The plasma actuators are installed on the top surface and the rear surface of the square cylinder. The induced flow velocities of the plasma actuators are modulated by adjusting the operating voltage and frequency of the high-voltage generator. In this work, particle image velocimetry (PIV) is used to obtain the velocity fields. Furthermore, force calculations are conducted to investigate the effect of using plasma actuators with different driving voltages on the drag force. Our results show that the plasma actuators can successfully suppress flow separation and reduce the turbulent kinetic energy (TKE) in the wake. A correlation between the drag coefficient and the operating voltage of the power generator is also revealed, and the mean drag coefficient is found to decrease with increasing imposing voltage. The plasma actuators can enhance the momentum exchange and the interactive behavior between the shear layer and the flow separation region, resulting in flow reattachment at the free end and shrinkage of the recirculation zone in the near-wake region of the bluff body. Overall, the present study demonstrates the practical effectiveness of using plasma actuators for flow control around FWMSC.

Parallel Operation Strategy of Inverters Based on an Improved Adaptive Droop Control and Equivalent Input Disturbance Approach

The operation of parallel inverters in microgrids is an important way to expand system capacity, but there are problems of circulating current fluctuations and power sharing errors in parallel inverters’ operation. In this paper, a parallel operation strategy for inverters based on improved adaptive droop control and Equivalent Input Disturbance (EID) is proposed. Firstly, the model and control topology of parallel inverters are presented. Secondly, in order to solve the power sharing error caused by impedance difference and the voltage drop caused by virtual impedance, a reference voltage generator based on improved adaptive droop control is proposed. Then, considering the circulating current fluctuation as a disturbance, a voltage controller based on an equivalent input disturbance approach is proposed to reduce the disturbance. Finally, simulation in MATLAB/Simulink is carried out to verify the effectiveness of the parallel operation strategy.

Two-speed Synchronous Generator for Special Purposes

This paper deals with basic performances of a design of a two-pole three-phase 40MVA synchronous generator. The generator is designed to test three-phase and single-phase high power transformers aimed to work within 50 Hz and 60 Hz network frequency. This means that the generator will operate at two nominal speeds, at 3000 rpm and 3600 rpm, with nominal power of 40 Mvar induction load when rating with symmetrical three-phase load. The additional requirements relate to constant operation with two-phase 25 MVA load and single-phase 13.5 MVA load, since for testing single-phase and special transformers phase connection you like will be used. In the course of designing, special attention was paid to correct dimensioning of the damper rotor winding as well as to the geometry of stator windings, rotor and air gap, which in the end will produce minimum voltage wave distortion, i.e. generator voltage wave shape with harmonious content less than 1% (as it was demanded).

Design of Low Power Analog/RF Signal Processing Circuits Using 22 nm Silicon-on-Insulator Schottky Barrier Nano-Wire MOSFET

The gate-all-around (GAA) silicon-on-insulator (SOI) Schottky barrier (SB) nano-wire (NW) MOSFET was recently proposed for low-power and high-frequency analog and radio frequency (RF) circuits. But their use in low-power and high-frequency analog/RF circuits is still under investigation. In this work, basic analog signal processing circuits using gate-all-around SOI-SB-NW MOSFETs are designed for low-power and high-frequency applications. These basic and necessary analog processing circuits are designed for ± 0.3 V and ± 0.25 V power supplies to work on frequencies up to 10 GHz. The analog/RF characteristics of the GAA SOI-SB MOSFET are compared with those of the GAA SB NW MOSFET. The SOI-SB NW MOSFET shows improvements in early voltage, output resistance, and transconductance generation factor. The Silvaco TCAD simulator is used to obtain the results and perform numerical simulations. Simulation results show good analog/RF performance of the analog processing circuits.