Measured Output Voltage Research Articles

Filter‐based control of a buck converter for uncertain non‐linear loads

In this study, a filter-based control scheme is proposed for dc–dc buck-type converters. Primarily, this control scheme reduces costs by requiring only a single output voltage measurement, removing the need for potentially noisy current measurements. The proposed controller is compared with a Type III error amplifier, which is a linear controller commonly used for buck-type converters. The performance of these controllers is compared when applied to linear and non-linear loads. A Lyapunov stability analysis is utilised to demonstrate the system stability of the proposed control scheme. Experimental results demonstrate excellent voltage regulation and insensitivity to the load variations for the proposed controller as compared to Type III controller.

High-performance lead free piezoelectric Y2O3-Ba(Ti0.96Sn0.04)O3 nanofibers based flexible nanogenerator as energy harvester and self-powered vibration sensor

Efficient, eco-friendly, flexible and high energy output piezoelectric nanogenerator is very much desirable for the development of multifunctional miniaturize devices and sensors. Aspect ratio ~ 102 and boosted energy harvesting attributes of lead-free piezoelectric Y2O3-Ba(Ti0.96Sn0.04)O3 nanofibers have considered for fabricating a flexible nanogenerator. The nanofibers have been synthesized using sol–gel and followed by electro-spinning process. The sintering temperature optimizes at 700 °C to obtain the best quality nanofibers having a diameter in the range from 67 to 132 nm. Rietveld refinement analysis of the X-ray diffraction pattern revealed the substitution of yttrium 30% on titanium (B-site) and 10% on barium (A-site) sites of ABO3 structure. Efforts have made for the development of Y2O3-Ba(Ti0.96Sn0.04)O3 nanofibers based nanogenerator using a simple, cost-effective and scalable approach. The open-circuit voltage (peak-peak) ~ 25 V and the maximum power density ~ 6.5 mW/cm3 have obtained from the developed nanogenerator. Further, the performance of the Y2O3-Ba(Ti0.96Sn0.04)O3 nanofibers based nanogenerator is investigated as a frequency sensor by measuring output voltage as a function of frequency.

Digital V2 Constant ON-Time Control Buck Converter With Adaptive Voltage Positioning and Automatic Calibration Mechanism

This article presents a digital V2 constant on -time control buck converter with adaptive voltage positioning (AVP) and automatic closed-loop output impedance ( Z oc) calibration for advanced system-on-a-chip processors. To ensure that the output voltage deviation remains within the desired range, the system is equipped with AVP. For an optimal AVP design, the system includes a second-order digital inductor current sensor for deriving a constant Z oc within a wide bandwidth. A detailed system-level analysis was performed to design the proposed control architecture. Considering the inevitable variation and aging of power stage components, the system is equipped with an online real-time Z oc calibration mechanism established to ensure the performance of AVP control. A prototype chip was fabricated using a 90-nm complementary metal–oxide–semiconductor (CMOS) process. The digital controller was fully realized using a standard cell library. Under a 0.9-A load transient, the measured output voltage could be adequately constrained within a specified 1.1-V and 110-mV AVP window.

A 1.16-V 5.8-to-13.5-ppm/°C Curvature-Compensated CMOS Bandgap Reference Circuit With a Shared Offset-Cancellation Method for Internal Amplifiers

This article introduces an accurate current-mode bandgap reference circuit design with a novel shared offset compensation scheme for its internal amplifiers. This bandgap circuit has been designed to operate over a very wide temperature range from −40 °C to 150 °C. Its output voltage is 1.16 V with a 3.3-V supply voltage. A multi-section curvature compensation method alleviates the error from the bipolar junction transistor’s base–emitter nonlinear voltage dependence on temperature. The bandgap reference circuit contains two operational amplifiers that are utilized to generate proportional-to-absolute-temperature (PTAT) and complementary-to-absolute-temperature (CTAT) current sources. With the implementation of the described shared offset-cancellation methodology, the simulated output inaccuracy introduced by the amplifier is kept to a 5 $\sigma $ offset within ±4.6 $\mu \text{V}$ while allowing to conserve die size and power consumption by preventing that each amplifier is accompanied by its own active auxiliary offset-cancellation circuit. Designed and fabricated in a 130-nm CMOS process technology, the bandgap reference has a measured output voltage shift of less than 1 mV over a −40 °C to 150 °C temperature range and an overall variation of ±8.2 mV across seven measured samples without trimming.

DETECCIÓN DE FALLOS EN CONJUNTOS FOTOVOLTAICOS: UN ENFOQUE ROBUSTO Y REGULARIZADO DE APRENDIZAJE DE MÁQUINA

In this paper, a robust data-driven method for fault detection in photovoltaic (PV) arrays is proposed. Our method is based on the random vector functional link networks (RVFLN) which has the advantage of randomly assigning hidden layer parameters with no tuning. To eliminate the effect of measurement noise and overfitting in the training process which reduce the fault detection accuracy, the sparse-regularization method is utilized which uses l2-norm with loss weighting factor to compute the output weights. To attain strong robustness against the outlier samples, the non-parametric kernel density estimation is employed to assign a loss weighting factor. Through rigorous simulation and experimental studies, we validate the performance of our proposed method in detecting the short and open circuit faults based on only the output current and voltage measurements of PV arrays. In addition to stronger robustness comparing with the least square-support vector machine, we also show that our proposed method provides 80% and 100% average detection accuracy for short circuit and open circuit, respectively. Key Words: Canonical correlation analysis, fault detection, photovoltaic array, random vector-link network, sparse regularization

A Practical Circuit Design for Measuring Output Voltage of High Voltage Frequency-modulated Power Supply

At present, the measurement of output high voltage at intermediate frequency or high frequency of AC power supply relies too much on expensive experimental equipment such as oscilloscope and high-voltage probe. In response to this problem, a design of measuring circuit of the output high voltage at intermediate frequency or high frequency of AC power supply is proposed. In this design, the output high voltage is sampled by setting tap on the high voltage side of the power transformer and using compensation capacitance. The AC voltage obtained by sampling is then converted into DC voltage and measured on gauge outfit. At the end of the article, the experiment shows that the design scheme in this paper has very small error in measurement and can meet the requirements of high voltage experiment for measurement accuracy. High-voltage AC power supply with this circuit can display the measurement of its output high voltage independent of expensive experimental equipment such as oscilloscope and high-voltage probe. Consequently, high-voltage AC power supply with this circuit can help save the cost of experiments and becomes more intelligent and more portable in the experimental situation where researchers are desired for the value of high voltage at intermediate frequency or high frequency output by high-voltage AC power supply.

Miniatur Sistem Pembangkit Listrik Tenaga Air Piko Hidro Sebagai Media Pembelajaran Pada Politeknik Bosowa

This study aims to make a miniature Pico Hydro-Hydro Power Plant (PH-HPP) system with load variations. The research method used in this research consists of the stages (1) identification of the problem, (2) design, (3) development and (4) application. Based on the results of observations at the development stage, the number of revolutions using one nozzle was greater than 29%, namely 1080 rpm for one nozzle and 758 rpm for 2 nozzles. The measured output voltage when using a 3 watt load is 142 VAC and the measured voltage when using a 100 watt load is 106 VAC. The measured output voltage on the control panel is inversely proportional to the load given, and this is because the higher the wattage load on the lamp, the heavier the generator rotates so that the output voltage on the generator is getting smaller.

Piezoelectric energy harvesting experiments under combined aerodynamic and base excitation

The behavior of film-type piezoelectric energy harvesters under simultaneous aerodynamic and base excitation was experimentally investigated. Two flutter type piezoelectric film transducers (LDT0-028K and LDT1-028K) were excited with the 31 excitation mode. The aerodynamic excitation was produced by a centrifugal fan. The base excitation was produced by a cone speaker driven by sinusoidal voltage waveforms in the frequency range of 20 to 250 Hz. This frequency range includes the two transducers’ resonant frequencies. The voltage output of the harvesters was monitored by an oscilloscope and the base excitation was monitored with acceleration measurements. The measured output voltage signals were analyzed by Fast Fourier Transformation. The tip deflection of the piezo-films was monitored with long exposure photography. Harvesting power output was estimated by simple calculations. The results are discussed aiming to support the optimal design of vibration energy harvesting layouts with piezoelectric transducers. To this end, information was extracted about the exploitable bandwidth of piezoelectric films.

Liquid Metal-Based Wearable Tactile Sensor for Both Temperature and Contact Force Sensing

Wearable tactile sensors can be used for haptic perception and are widely utilized in soft robotics, intelligent prosthetics, and other human interfaced/interface applications. The development of tactile sensors with for multifunctional tactile sensing capacity remains a challenge. This article presents the design and fabrication of a wearable tactile sensor based on galinstan liquid metal for the simultaneous sensing of temperature and contact force independently. The decoupling of temperature and contact force sensing, which is based on the measured output voltage signals, is achieved by a designed Wheatstone bridge circuit and by the structural design of the fingerprint-patterned microfluidic channels and the top oval-shaped protrusion. Characterization tests show that the fabricated tactile sensor has a relatively high force sensing sensitivity of 0.32 N <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> and its temperature sensing sensitivities are 0.41% °C <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> at 20~50 °C and 0.21% °C <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> at 50~80 °C. Two wearable tactile sensors are worn on the index finger and thumb of the human hand and are used to detect temperature changes and contact forces during grasping applications. The results show that the developed liquid metal-based tactile sensor has a high flexibility and durability, and can accurately measure the contact forces and temperatures simultaneously. Thus, the developed wearable tactile sensor has great potential for robotic manipulation and healthcare condition sensing in humans.

Low-Power Area-Efficient LDO With Loop-Gain and Bandwidth Enhancement Using Non-Dominant Pole Movement Technique for IoT Applications

A new Low Drop-Out (LDO) voltage regulator with off-chip capacitor for low power applications is presented. The LDO takes advantage of non-dominant pole movement technique to improve loop-gain and Unity Gain Frequency (UGF). Tangible improvements were obtained while supporting a large load capacitor and low-power consumption. The proposed LDO 1) consumes low quiescent current (47.3% current efficiency (CE) at 10 μA load current bias circuit inclusive), 2) is area-efficient (no multi-gain amplifiers), and 3) enjoys a short response time in the active-mode with its adaptive bandwidth expansion and loop-gain enhancement technique, while 4) maintaining 99.94% CE in the full-load condition. A prototype chip with TSMC 180 nm CMOS technology was fabricated for detailed characterisation. The measured output voltage of the LDO was 1.65 V with 1.8 V input, consuming 11 μA quiescent current including the bias circuit current. The load regulation was 10 mV when load current changes from 30 nA to 50 mA with fall and rise time of 10ns.

Design of Stage-Selective Negative Voltage Generator to Improve On-Chip Power Conversion Efficiency for Neuron Stimulation

Dedicated to neuron stimulation circuits, a stage-selective negative voltage generator is proposed to enhance the overall power efficiency. Since the supplied voltage of the stimulus driver is subject to applications and treatments, an extensive output requirement of supply is demanded to achieve energy-efficient stimulation. The charge pump is implemented as a negative voltage generator for on-chip design. In a limited area, excess power loss is eliminated by reconfiguring the cascaded architecture and clocks. Digitally programmable voltage levels can be outputted by varying the number of stages dynamically. The function of stage selection is achieved by the proposed stage-selective scheme. With appreciate control, the stage-selective negative voltage generator can maintain higher power efficiency under different output voltage levels and loading conditions. The technique improves 40% power conversion ratio at most but only leads to an increment of 8% in area occupation. The measured output voltage covers from -0.3 V to -9.3 V within a maximum 5.5-mA output current, which is verified in a 0.25-μm BCD process.

A Simple Approach for Determination of Numerical Values of Ferrite Nonlinear Susceptibilities

This article presents a straightforward approach for determination of numerical values of nonlinear susceptibilities of soft magnetic ferrites. It is shown that numerical values of susceptibilities can be calculated from the measured amplitudes of harmonics in the output voltage of ferrite core transformer. For this purpose, useful expressions for the susceptibilities are derived and as example, numerical values of the largest nonlinear susceptibilities those of the third and fifth orders are calculated. Additionally, errors of the measured susceptibilities also are determined. Based on the expressions obtained, the analysis of phase shifts between components of flux density on different frequencies and the magnetic field strength also is performed. The comparison of the calculated and measured output voltage waveforms allows concluding that in the frequency range where losses are small and can be neglected, the susceptibility of the third order is negative but that of the fifth order is positive.

Piezoelectric properties of paint sensor according to piezoelectric materials

The objective of this paper is to study the performance of piezoelectric materials on a piezoelectric paint sensor. The paper begins by presenting a fabrication method for a paint sensor with piezoelectric properties using piezoelectric materials. The paint sensor is composed of piezoelectric powder and epoxy resin in a 1:1 weight ratio. Five different piezoelectric materials, including three soft-type and two hard-type materials, were used and their piezoelectric properties compared in paint sensors and ceramic sensors. The paint sensors were cured using a steel mold for producing a uniform specimen size of 20 × 10 × 0.2 mm3, and an electrode was made on the upper and lower sides using silver paste. Poling treatment was then successfully performed at room temperature (20 °C) under a 4 kV mm−1 electric field for 30 min in order to activate the paint specimen as a sensor. Impact signals were monitored by measuring output voltage from the paint sensor in relation to impact force. The sensor’s piezoelectric properties were then calculated using normalized piezoelectric properties. In addition, five different piezoelectric ceramic sensors were fabricated and their d33 value measured to compare the sensitivity of paint sensors. As a result, Pb(Ni1/3Nb2/3)O3-Pb(Zr, Ti)O3 (PNN-PZT) powder showed higher sensitivity and higher piezoelectric properties than other piezoelectric materials in both paint and ceramic sensors.

Measurement of induced currents in radio frequency magnetic fields based on near field antenna perturbations

A measurement system is developed utilizing electromagnetic compatibility test equipment for the study of induced current in conductive materials subjected to radio frequency (RF) magnetic field strengths similar to the 1.5 T magnetic resonance imaging (MRI) B1 magnetic field at ∼65 MHz. The intent of developing such a system was to produce μT range RF magnetic fields in the laboratory to facilitate characterization of induction in conductive materials with modified surface electromagnetic properties to address unintended eddy current issues like Joule heating caused by implanted devices during MRI. A Helmholtz coil (HHC) is used as the RF magnetic field source, and the radiated field is monitored using a receiving loop antenna positioned coaxially outside the HHC. The measurement system operates in continuous wave and pulsed wave modes. Analytical models of the system were derived, which calculate the spatial distribution of RF magnetic flux and the induced current within a coaxially located sample in the transmission path between the HHC and receiving (R/C) loop from output voltage measurements at a single coaxial position. Induced currents were evaluated at multiple flux densities and at different frequencies, showing direct proportionality over the flux densities tested. Induced current results recorded in samples of different sizes and electrical conductivities (ranging from 0.1 to 5.8 × 107 (Ω m)−1 produced changes, matching trends predicted by conductive, closed-loop antenna theory. Induced currents were also used with simultaneous temperature rise measurements to characterize the effective surface conductivity for wire with non-uniform properties at 65 MHz.

A new method for optimal parameters identification of a PEMFC using an improved version of Monarch Butterfly Optimization Algorithm

In this paper, a circuit-based model of proton exchange membrane fuel cell (PEMFC) is developed for optimal selection of the model parameters. The optimization is based on using an improved version of Monarch Butterfly Optimization (IMBO) algorithm for minimizing the Integral Time Absolute Error between the measured output voltage and the output voltage of the achieved model. For validation of the proposed method, two different case studies including 6 kW NedSstack PS6 and 2 kW Nexa FC PEMFC stacks have been employed and the results have been compared with the experimental data and some well-known metaheuristics including Chaotic Grasshopper Optimization Algorithm (CGOA), Grass Fibrous Root Optimization Algorithm (GRA), and basic Monarch Butterfly Optimization (MBO) to indicate the superiority of the proposed method against the compared methods. Final results show a satisfying agreement between the proposed IMBO and the experimental data.

A novel fault diagnostic method in power converters for wind power generation system

In order to decrease the downtime, enhance maintenance efficiency, and reduce the management cost of the wind power system, fault diagnosis technologies are considered as powerful tools for its good operation and maintenance. For example, high fault diagnosis accuracy can ensure effective fault-tolerant control and improve the durability of wind turbines under fault conditions. However, fault diagnosis accuracy can be easily affected by nonlinear and noise of measured signals under different working conditions. In this paper, a novel fault diagnostic method of power converters is proposed for the wind power generation system. In the proposed method, the measured output voltage is firstly processed by ensemble empirical mode decomposition (EEMD), and a series of intrinsic mode functions (IMF) can be obtained. Norm entropy (NE) is then calculated based on the statistical characteristics of the IMFs, and the extracted IMF-NE information is used to describe the diagnostic features. The effectiveness and reliability of the proposed method are then validated in a simulated 1.5 MW doubly-fed wind power system. The results show that the final diagnostic accuracy of 22 fault modes is 99.57% for wind speed variation, and the diagnosis accuracy can be maintained above around 70% for different signal to noise ratio. Compared with the other advanced fault diagnosis methods, the proposed method shows outstanding performance in terms of robustness, high accuracy, and simple implementation without complex parameter tuning.

Optimal parameter extraction of PEM fuel cells by meta-heuristics

This paper represents a new technique for optimal modelling and simulating a proton exchange membrane fuel cell (PEMFC) system to assure dependable modelling. The main idea is to utilise a newly developed meta-heuristic, called Chaos Owl Search Algorithm (COSA) to optimal selecting of the model parameters of the PEMFC stacks by minimising the Sum of Squared Error (SSE) between the estimated and the measured output voltage for two different case studies. By applying 50 independent runs with the algorithm, it is analysed and compared with some literature meta-heuristics including Bat Algorithm (BA) Firefly algorithm (FFA), and Multi-verse optimiser (MVO) in terms of convergence speed and minimum SSE. The final results declare that the proposed method achieves the best convergence speed in comparison with others. The results also determine the high efficiency of the presented method.

Levitating oscillator-based triboelectric nanogenerator for harvesting from rotational motion and sensing seismic oscillation

Ever-rising skyscrapers and the growing number of densely populated large cities face an increased danger from earthquakes. To lessen the risk of this natural disaster, critical facilities must be equipped by a reliable warning system. However, conventional sensors which detect the velocity and acceleration of the seismic vibrations, consumes an external power, which cannot be placed in many buildings due to limitations in electricity supply. In this work, a self-powered seismic sensor is fabricated using the three-dimensional printing technology. The proposed device can be operated based on the triboelectricity, which converts an external mechanical energy into an electrical energy. The proposed device exhibits an exceptional behavior of a friction-free due to its sophisticated designed structure with a levitating oscillator. The fundamental parameters representing the device performance are systematically analyzed with various operation mode. Water-assisted oxidized Al electrodes allow full-contact with the polytetrafluoroethylene triboelectric oscillator film, subsequently, produce the highest values of output parameter as follows; an open-circuit voltage of 29.44 V, a short-circuit current of 204 nA, and a peak power density of 2.501 mW/m2 at a load resistance of 50 MΩ. Frequency reversibility is also demonstrated from the frequency response of the short-circuit current during the operation in lateral-contact mode. Because of inherently friction-free characteristics of the proposed device, this device shows high sensitivity, low sensing limit, and long residual signal, which is experimentally verified. In order to test the sensing ability of the device, artificial seismic vibrations are applied with vertical forces of 4 N and 2.4 N. An alert software program displays the sensing ability of the device with the signals over 1 V, which is the threshold voltage. The stability of the device in humid conditions and its durability for 3100 s in the output voltage measurement represent the possibility of this device as a reliable sensor. Due to the simple three-dimensional printing technology and its inherently friction-free characteristics, the proposed device can be employed as a self-powered sensor capable of warning about dangerous earthquake disasters.

Maximum Power Point Tracking Using Disturbance Observer-Based Sliding Mode Control for Estimation of Solar Array Voltage

The output power of solar panel in photovoltaic systems is affected by changes in environmental and load conditions. Most currently developed MPPT control algorithms require measurements of panel output voltage, output current, and converter output voltage. In this paper, a new scheme that can cater to uncertainties in the environmental and load condition, is developed using a disturbance observer-based sliding mode control (DOSMC). The proposed DOSMC scheme obviates the need of using a panel output voltage sensor. The proposed scheme does not use a discontinuous control, thereby overcoming the problems of chatter normally associated with the conventional sliding mode control (SMC). The stability is proven in the sense of ultimate boundedness. The proposed scheme is validated by extensive simulation and laboratory experimentation under various scenarios of irradiation, temperature, and load conditions and compared with two existing popular schemes.

Eco-friendly biopolymer kappa carrageenan with NH4Br application in energy saving battery

Preparation of biopolymer electrolyte based on kappa-Carrageenan with ammonium bromide (NH4Br) by means of solution casting manufacturing method using condensed back H2O as a solvent. Non crystalline characterization between the biopolymer (kappa-Carrageenan) and salt (NH4Br) has been investigated by XRD (X-ray diffraction) characterization. Glass transition temperature of the prepared sample is studied by DSC and its 32.08 °C for highest conducting biopolymer membrane. The conductivity value measured by the conductivity study for 1 gm kappa-Carrageenan with 300 mg NH4Br is 2.80 × 10−3 S/cm. The proton conducting battery has been fabricated and the measured output voltage is 4.29 V.