Output Voltage Research Articles

A dual wave structure triboelectric sensor for heart rate and exercise monitoring

Recently, research on wearable devices for physiological exercise monitoring has garnered significant attention. Here, we propose a dual wave-structured triboelectric nanogenerator (DW-TENG) integrated with a cotton cloth, developed for smart running applications. The DW-TENG sensor leverages a flexible wave triboelectric layer composed of polydimethylsiloxane and silicone, with a copper electrode layer between them for sensing. This structure allows for customizable pressure sensitivity by adjusting the silicone hardness. Experimental results show that the DW-TENG achieves a sensitivity of 0.4 V kPa−1, with response and recovery times of 75 and 90 ms, respectively. The sensor effectively measures heart rate changes during various physical activities, including walking, running, and jumping. Electrical performance tests reveal that the DW-TENG’s output is significantly influenced by the silicone hardness, operational frequency, and microstructure height. The DW-TENG sensor demonstrates high durability and stability, maintaining consistent voltage output over 40 000 cycles. This research highlights the potential of the DW-TENG in multifunctional physiological and physical activity monitoring, providing real-time data on respiratory patterns, heart rate, and movement dynamics, thus enhancing athletic training, performance assessment, and health monitoring.

The Role of EM4 (Effective Microorganisms) in Solid Waste-Powered Microbial Fuel Cells: Investigating Voltage Output and Electrical Conductivity For Bioelectricity Generation

The increasing global demand for renewable energy and sustainable waste management solutions has inspired interest in microbial fuel cells (MFCs) as a dual-purpose technology for bioelectricity generation and waste treatment. This study explores the role of EM4, a consortium of effective microorganisms, in enhancing the voltage output and electrical conductivity of solid waste-powered MFCs. A batch system bioreactor assessed the impact of varying organic waste-to-zeolite ratios on MFC performance. The results demonstrated that a 1:1 ratio of organic waste to zeolite produced the highest electrical conductivity (3160 µS/cm) and the most substantial voltage output (777.5 mV) by day three of the experiment. Statistical analysis, including ANOVA and Kruskal-Wallis tests, revealed significant differences in voltage output across treatments, with a positive correlation between electrical conductivity and voltage production. These findings highlight the potential of integrating EM4 and conductive materials like zeolite to optimize bioelectricity generation in MFCs, contributing to the advancement of sustainable energy technologies.

Implementation Joule Thief Buck-Boost Converter in A Neodymium Wind Power Plant

Wind power generation is gaining popularity as an environmentally friendly renewable energy source. However, the output voltage of a wind generator usually varies according to the wind speed, requiring a power converter to produce a stable DC voltage. The author of this research aims to implement a Joule Thief Buck-Boost Converter on a neodymium wind power generation system. Joule Thief is a DC-DC converter that has the ability to convert a low input voltage into a higher output voltage, and can maintain a relatively stable output voltage despite changes in the input voltage. In this study, a Joule Thief buck-boost converter is used to regulate the output DC voltage of the neodymium wind generator to remain stable despite the changing wind speed. System testing is done by measuring the output voltage of the neodymium wind power plant. The test results show that the Joule Thief Buck-Boost Converter can maintain the output DC voltage at a stable value of 14V at input voltages above 3V, so the implementation of this converter in neodymium wind power plants is proven effective in producing a stable DC voltage. This research is expected to contribute to the development of a more efficient and reliable wind power generation system.

High-Frequency Modified Bridgeless AC-DC PFC Rectifier for Ceiling-Fan

High current percentage total harmonics distortion (%THD), low supply power factor (SPF), and high input-power are main concern in an existing brushless direct current motor ceiling-fan (BLDCMCF). This paper presents AC-DC coupled-inductor-based bridgeless switched-inductor Cuk-converter (CIB-BLSICC) for BLDCMCF to address these concerns. CIB-BLSICC improves supply power quality (SPQ) and reduces input-power. Switched-inductor branch using coupled-inductor provides high-step-down-gain (HSDG), which offers an appropriate operating duty for BLSICC. Front-end CIB-BLSICC is developed in discontinuous mode (DCM) with changeable output voltage and a low component count, which reduces converter's overall size. DCM design offers auto power-factor correction (PFC) at a supply-mains. Variable output-voltage makes voltage source inverter (VSI) control easy (offers inverter switching at fundamental-frequency) with low switching-losses and helps speed-control. In addition to improving CF's (ceiling-fan's) overall efficiency, bridgeless design of PFC-converter lowers losses caused by conduction. Using reference speed of fan, CIB-BLSICC calculates its operational duty in order to create fixed-frequency PWM-pulses (200 kHz) while supply-voltage remains constant. This simple-control brings CF's price down by removing need for a sophisticated sensing-circuit, a DC-link sensor, and a voltage-controller. Test results confirm concept and design, which demonstrate a %THD of 1.483%, a crest-factor of 1.48, SPF of 0.9991, and a power-input of 27.93 W.

Novel nine level switched capacitor multi-level inverter based STATCOM for distribution system

FACTS based devices are mostly used in power systems due to their capacity to improve system stability. The Static Synchronous Compensator (STATCOM), a shunt-connected device in the FACTS device family, is used for power compensation, power balancing, and enhancing dynamic stability in contemporary power systems. In the proposed work, STATCOM based novel nine level switched capacitor based multi-level inverter (MLI) is used to reduce power quality issues. The proposed novel inverter has a few number of switches with one voltage source. The placement of STATCOM based inverters in the wrong places may have detrimental effects on power loss and electricity quality. To overcome these issues, green anaconda optimization (GAO) is used to allocate the proposed system in an optimal place. The performance of the proposed inverter is examined using the MATLAB/Simulink tool. This inverter requires fewer switches and achieves DC link voltage balances in comparison to any other existing conventional topologies. STATCOM based inverter is validated under different faulty conditions to show the effectiveness of this inverter. The proposed new inverter has nine levels and compensates for the poor state while improving power quality. The proposed method has a substantially lower total harmonic distortion (THD) of 1.04 % while maintaining an efficiency of 99.02 %. Experimental validation is established using a dSPACE RTI1104 controller to validate the proposed method. Experimental results obtained 1.04 % of harmonics with the same output voltage as the simulation.

Adaptive hysteresis compensation control of a macro-fiber composite bimorph by improved reinforcement learning

The hysteresis characteristics related to the frequency and amplitude of the control signal seriously affect the precision of the displacement tracking control of the macro-fiber composite (MFC) bimorph. The traditional feedforward compensator tends to exhibit low precision in controlling displacement. Although it enhances the control accuracy to a certain extent by incorporating a feedback controller, the existing feedback controller has a weak adaptive ability. Thus, the Q-learning (QL) algorithm is combined with the Bouc-Wen (BW) feedforward compensator in this study. The output voltage from the BW compensator has a more significant impact on the control accuracy and convergence speed of the QL algorithm. Therefore, this paper proposes an improved QL (IQL) algorithm that leverages the control error. Moreover, a BW-IQL adaptive control method is proposed to realize precise adaptive control of the MFC bimorph. Experimental comparisons are performed with the proposed method and the traditional BW, BW-PID, and BW-fuzzy PID controllers. The BW-IQL controller reduces the average relative errors of the three controllers by 86.9%, 59.9%, and 41.8%, respectively. Meanwhile, the Q̄ table plays a major role in error suppression in the IQL controller. These results verify that the BW-IQL control method has higher adaptability and accuracy.

Quasi‐Z‐source interleaved DC‐DC converter for fuel cell vehicle application

AbstractIn this study, a step‐up DC‐DC converter with a combination of a two‐phase interleaved structure and a quasi‐Z impedance network is proposed for fuel cell vehicle application. The operation of the converter in a small duty cycle (0 < D < 0.5) reduces the conductive losses of the switches and as a result increases the efficiency of this converter compared to conventional boost converters. Also, due to the common ground between the input and output, unlike the floating interleaved boost converter (FIBC) and the parallel input‐series output converter (PISO), it does not face the problem of imposing additional EMI on the converter circuit. This converter has a low input current ripple, suitable voltage gain for fuel cell vehicles system, as well as high reliability due to the ability to operate with one phase in case of failure in the other phase. It can be a suitable candidate for practical application in fuel cell vehicles. The principles of operation and the main characteristics of the converter such as voltage gain, input current ripple, and voltage and current stress of the elements are explained and also a 120‐W experimental prototype with 12‐V input voltage and 60‐V output voltage is made to validate the theoretical analysis results.

Modelling and Analysis of Adaptive ON-Time Controlled Boost Converter Using Verilog-A

ABSTRACT This paper presents a mixed modelling of adaptive ON-time controlled boost converter using Verilog-A. It is a mixture of Mathematical modelling, Behavioural modelling, and discrete components. While mathematical modelling has been used to model individual components, for circuits such as comparator and pulse generator behavioural modelling is used. Power MOSFETs in the power stage are the only discrete components used from the library. Each model was coded using Verilog-A in Cadence Virtuoso and its symbolic notation obtained. The symbols were then connected to obtain the complete schematic of the boost converter. The behavioural modelling of the boost converter is targeted for an output voltage of 1.2 V for an input voltage ranging from 0.5 to 0.7 V and switching frequency of 800 KHz. The modelling also captures the results for 40% variation in input and load, for which the output voltage is found to vary by about 5–6%. This work is an attempt at completely modelling a complex analog circuit. It also shows the successful integration of modelled components with discrete components. To validate the results obtained, the performance of the modelled converter is compared with that of circuit simulation, with both simulations being conducted at identical operating conditions. The results obtained with modelling simulation match that obtained with the circuit simulation.

Wall Follower Based Fire Extinguisher Wheeled Robot Prototype using 5 Channel Fire Sensor

Fires can occur anywhere, be it in schools, offices, and housing or other open spaces. Fire cannot be predicted when it will happen. In the modern era robots are one of the very special technologies, the benefits of these robots can facilitate human work. Robot cars in this era are attracting quite a lot of attention from experts to develop. Therefore, the author designed a "Wall Follower-based Fire Extinguishing Robot using a 5 Channel fire sensor" to reduce the risk of fire. This robot uses the HC-SR04 sensor to detect the barrier wall so that the extinguishing robot reaches the fire point. For the microcontroller tool used in this design system in the form of an Arduino Nano microcontroller which functions as part of the 5 Channel Flame Sensor controller to detect hotspots and a DC water pump to extinguish the fire. In this study using experimental research. This robot has successfully passed the track and put out the fire as the author has designed. The average flame sensor on this robot can read the fire point at a distance of 20 cm with angles of 90°, 60°, 120°, 150°, then the output voltage generated on the DC motor with a PWM value of 191 or 75% duty cycle produces an output of 8.77V measured using a multimeter, and this robot can extinguish the fire on the track with different distances with an average fire extinguishing time of 7.1 seconds.

Performance enhancement energy harvesting from aeroelastic vibrations using a van der Pol circuit

This paper explores galloping vibration-based electromagnetic energy harvesting (EH) in a Duffing-Rayleigh oscillator coupled to a storage RLC resonator circuit with a van der Pol model. Aeroelastic instability induces the mechanical system’s self-induced vibration. The electromechanical coupling mechanism between the resonant van der Pol circuit and the mechanical structure is obtained by the permanent interaction of the magnet and the coil. We examine two cases in a comparative study. In the first case, we use an RLC resonator circuit without a van der Pol model. The second case considers the RLC resonator circuit with a van der Pol model. Firstly, the modulation equations of slow flow of the vibration and the output voltage responses are obtained using a complexification-averaging (CX-A) method. Furthermore, the analytical approximate solutions of the steady-state responses are derived. The obtained analytical results have been confirmed using numerical simulations. Results show that the Duffing-Rayleigh mechanical oscillator can provide higher electrical energy by introducing a van der Pol circuit instead of without a van der Pol circuit. Moreover, the presence of the van der Pol model with the RLC circuit can significantly reduce the critical wind speed required to harvest energy. This result may provide an optimization process that can be used to supply some guidelines in the design of galloping vibrations-based electromagnetic energy harvesters.

Chaotic responses across the potential barrier of bistable vortex-induced vibration energy harvesters

Large-amplitude interwell limit cycle oscillations (LCOs) are regarded as an ideal high-output state of multistable vibration energy harvesters. However, chaotic responses, which result in lower output voltages than interwell LCOs, can be observed in bistable vortex-induced vibration energy harvesters (VIVEHs). In this paper, the chaos in bistable VIVEHs is investigated through numerical simulation, theoretical analyses, and experimental validation. The distribution of the periodic solutions obtained by the incremental harmonic balance (IHB) method and chaos judgment using Lyapunov exponents are elucidated. It is found that the bistable VIVEH shows intrawell periodic solutions at high reduced wind speeds (RWSs) and period-doubling bifurcation appears with the periodic solutions turning into chaos with decreasing RWS. Analyses of the influence of nonlinear parameters on the chaotic responses identify the nonlinear stiffness as the dominant factor contributing to the chaos. Meanwhile, the chaotic responses and interwell LCOs would exist at the same RWS with different initial states. Finally, wind tunnel experiments confirm the occurrence of homologous chaotic responses of the bistable VIVEH which feature aperiodic jumping back and forth motion between two potential wells, in agreement with numerical simulations. Overall, this paper provides a framework for analyzing the chaotic responses of bistable VIVEHs, offering valuable insights for complex response mechanism understanding.

Conducted interference and voltage ripple suppression study in LLC resonant converter based on symmetric chaotic spread spectrum

ABSTRACT Spread-spectrum modulation technique can effectively reduce the peak value of conducted interference in automotive LLC DC/DC converters, but it will bring more serious ripple problems to Class E resonant converters. In this paper, we investigate the voltage ripple trend of LLC resonant converter when applying spread-spectrum modulation, and propose a chaotic signal sampling rule under the minimum output voltage ripple. A symmetric chaotic spreading method is proposed to reduce the output voltage ripple from the source by changing the distribution sequence of the chaotic signal to make it centrosymmetric. The symmetric chaotic spread spectrum is simulated and analysed to be able to suppress the conduction interference while reducing the voltage ripple, and is verified by experiments. This modulation strategy does not require the addition of auxiliary circuits and additional control links, which saves cost and reduces the difficulty of designing control links.

Design of a Conformal Ablation System Based on Independent Control of Radiofrequency Electrode Arrays

This study aims to develop an independent control system for radiofrequency electrode arrays, intended for the conformal ablation of unwanted tissues. Unlike traditional single radiofrequency voltage applications, this study employs high-frequency transformer isolation and radiofrequency load matching technologies to divide the radiofrequency signal source into eight independent groups. Each group operates at the same phase and frequency but with different voltage values. Experimental results indicate that the designed system can independently output various combinations of radiofrequency signals. The actual output voltage has a relative error controlled within 6%, the frequency error is less than 0.5%, and the phase difference among the groups is less than 1°. In the biomimetic tissue heating experiments, it is found that by controlling the voltage of each electrode within the electrode array, ablation of different shapes can be achieved, and the ablation depth is positively correlated with the applied radiofrequency voltage.

A Novel NR-DA-Based ANN for SHEPWM in Cascaded Multilevel Inverters for Renewable Energy Applications

Harmonics is the major power quality problem caused by nonlinear devices, leading to malfunction or operational halt of the system. Low-order harmonics increase vibration and heat generation in motors. Therefore, controlling harmonics in the output waveform is the prime target for industrial applications to avoid economic loss. Selective harmonic elimination pulse width modulation (SHEPWM) is one of the techniques used for eliminating or minimizing selected harmonics in the output voltage waveform. This paper utilizes the Newton-Raphson method and Dragonfly Algorithms to calculate optimum switching angles for a Cascaded H-bridge Multilevel inverter (CHBMLI). The algorithms use non-linear equations to calculate the Switching Angles of MLI. The Dragonfly algorithm requires several iterations to reach an optimum solution. For complex problems, this algorithm becomes computationally expensive and time-consuming. A lookup table addresses the limitation by offline training an Artificial Neural Network (ANN) to generate the optimum switching angle for a given modulation index. Neural Fitting Tool in MATLAB software is used to train the ANN model. The simulation is performed using MATLAB SIMULINK software for both 5-level and 7-level CHBMLI configuration. The Dragonfly algorithm-based ANN achieves THD 8.84% when the modulation index (M) equals 0.8 for a 7-level inverter and THD 14.91% for a 5-level inverter and effectively minimizes third and fifth-order harmonics.

Modeling of Li-ion Battery Management System for Unmanned Aerial Vehicles

Nowadays, systems that use more electricity in aircraft are increasing due to harmful gas emissions. This increase has created the need to store electrical energy and accelerated the trend towards battery technologies. Since energy storage in batteries occurs as a result of chemical reactions, problems may occur that will damage the battery group or the entire system. These problems are caused by high current, voltage, and temperature, which affect the reaction rate during battery charging/discharging. A Battery Management System (BMS) is needed to prevent problems and to use the required electrical energy safely. In this study, it is aimed to meet the energy needs of the system in a controlled manner by disabling only the damaged cell in case of problems that may occur in the cells in the battery. For this purpose, a model of an Unmanned Aerial Vehicle (UAV) system been created by adding a BMS block to each cell to control the battery cells. The BMS model is realized based on the cell temperature, the State of Charge (SoC) value of the cell, and the output voltage values of the cell. The UAV system is modeled using MATLAB/Simulink environment. Thanks to the proposed BMS, in case of a problem that may occur in any cell in the battery, that cell will be disabled and the required energy will be met through the remaining cells. It is observed from the results obtained that when the cell parameters become normal, it continues to feed the system again.

Super Twisting Sliding Mode Control of Four-Phase Interleaved Boost Converter

This paper presents a novel control method that integrates super-twisting sliding mode (STSM) voltage control with proportional-integral (PI) current control for a four-phase interleaved boost converter (IBC) in fuel cell applications. The STSM control, employed in the outer voltage loop, provides robust voltage regulation by generating precise reference currents for each phase. The conventional PI control in the inner current loop utilizes these reference currents to generate pulse width modulation (PWM) signals for each phase. The effectiveness of the proposed control strategy is evaluated through comprehensive simulation studies in MATLAB/Simulink, demonstrating an improvement in dynamic performance and enhanced robustness compared to conventional methods. Quantitative analysis shows that the output voltage quickly rises to the reference voltage within approximately 0.25 seconds in the proposed STSM-PI control method and improves transient response by 16 times compared to the conventional PI-PI method. This integrated STSM-PI control strategy offers significant advancements in reliability and efficiency making it a promising solution for high-performance fuel cell power systems.

A Self‐Powered, Highly Sensitive, and Frequency‐Tunable Triboelectric Acoustic Sensor Inspired by the Human Cochlea

AbstractConventional acoustic sensors used in human–machine interfaces often face challenges such as power supply requirements, limited sensitivity, and inability to tune their frequency response. A self‐powered, highly sensitive, and frequency‐tunable triboelectric acoustic sensor inspired by the human cochlea is introduced. By mimicking hair cells in the organ of Corti, a tapered microhair‐structured ferroelectric poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) and barium titanate nanoparticle (BTNP) composite film is proposed, which demonstrates a 16‐fold increase in triboelectric output voltage (1.3 V) compared to a planar one at 2.8 Pa. Furthermore, inspired by the frequency selectivity of the basilar membrane with gradient structural variations, integrating a mass‐beam diaphragm is proposed with varying kirigami length and circular mass diameter that enables precise tuning of the resonance frequency of the sensor, resulting in a 32 times improvement in sensitivity (860 mV Pa−1) compared to a nonbiomimetic sensor (28 mV Pa−1) and an expanded dynamic range. The proposed sensor differentiates between human voices with different frequencies. A robotic hand integrated with the sensor responds to acoustic stimuli with programmed hand gestures, which highlights its potential in acoustic human–machine interfaces. The biomimetic approach to developing a self‐powered, highly sensitive, and frequency‐tunable acoustic sensor offers new possibilities for intuitive and immersive human–machine interfaces.

Robust integral super-twisting controller for enhanced photovoltaic integration with hybrid battery and supercapacitor storage in DC microgrid

This study relates to the enhancement in performance of a Hybrid Energy Storage System (HESS) over a DC microgrid, particularly toward a fast-accurate controller of the DC bus voltage. Conventional control methods are particularly difficult to implement in order to reduce start-up time with minimum overshoot, resulting in a significant disturbance of the DC bus voltage. To circumvent these problems, we propose an innovative hybrid controller method that combines the Integral Super-Twisting Algorithm (ISTA) controller technique with adaptive gain in regulating DC bus voltage and current. The capacity of ISTA to greatly enhance the system's dynamic responsiveness, guaranteeing steady operation with effective output voltage control, is by far its greatest benefit. Comparative testing found that the conventional PI controller had a rise time of 0.0666 s, a settling time of 0.165 s, and a 17 % overshoot with a steady-state error of 0.02 %. The proposed ISTA controller had a rise time of 0.0016 s, a settling time of 0.0667 s, zero percentage overshoot, and a minimal steady-state error of only 0.0003 %. The above-mentioned issues mostly focused on better sharing power in HESS and a more effective controller of the DC bus voltage. Furthermore, we evaluate the practical feasibility of the suggested controller through hardware-in-the-loop testing. This research lays a foundation for advancing renewable energy integration in DC microgrid, offering a promising avenue for sustainable and resilient power systems. Finally, the effectiveness and applicability of the proposed ISTA controller for DC microgrid use are proven with Controller Hardware-in-the-Loop (C-HIL) simulations.

Low-power ternary inverter using vertical tunnel field-effect transistor with pocket

ABSTRACT This paper proposes a vertical tunnel FET with pocket (VP-TFET)-based standard ternary inverter (T-inverter) model for low-power applications. Using TCAD Sentaurus tool and mixed-mode simulations, it is verified that the device can exhibit T-inverter voltage transfer characteristics (VTCs) with three steady output voltage levels when the doping length and concentration of the pocket are optimized The device’s T-inverter characteristics are achieved by employing channel-channel and source-channel tunnelling mechanisms. Current matching is crucial for n-/p–type devices to produce a steady third output voltage state. The proposed ternary inverter’s static noise margin (SNM) and static and dynamic power dissipations are computed to be 220 mV, 4.8 × 10−12 W, and 4 × 10−12 W, respectively, which assures better noise immunity and low power consumption compared to other models.

Graphene-Doped Piezoelectric Transducers by Kriging Optimal Model for Detecting Various Types of Laryngeal Movements.

This study fabricated piezoelectric fibers of polyvinylidene fluoride (PVDF) with graphene using near-field electrospinning (NFES) technology. A uniform experimental design table U*774 was applied, considering weight percentage (1-13 wt%), the distance between needle and disk collector (2.1-3.9 mm), and applied voltage (14.5-17.5 kV). We optimized the parameters using electrical property measurements and the Kriging response surface method. Adding 13 wt% graphene significantly improved electrical conductivity, increasing from 17.7 µS/cm for pure PVDF to 187.5 µS/cm. The fiber diameter decreased from 21.4 µm in PVDF/1% graphene to 9.1 µm in PVDF/13% graphene. Adding 5 wt% graphene increased the β-phase content by 6.9%, reaching 65.4% compared to pure PVDF fibers. Material characteristics were investigated using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), contact angle measurements, and tensile testing. Optimal parameters included 3.47 wt% graphene, yielding 15.82 mV voltage at 5 Hz and 5 N force (2.04 times pure PVDF). Force testing showed a sensitivity (S) of 7.67 log(mV/N). Fibers were attached to electrodes for piezoelectric sensor applications. The results affirmed enhanced electrical conductivity, piezoelectric performance, and mechanical strength. The optimized piezoelectric sensor could be applied to measure physiological signals, such as attaching it to the throat under different conditions to measure the output voltage. The force-to-voltage conversion facilitated subsequent analysis.