Output Voltage Variation Research Articles

Voltage boosting capability of three phase current source inverter for standalone system

This paper presents a three-phase current source inverter (CSI) topology with voltage boosting capability for standalone system. Current source inverter (CSI) and voltage source inverter (VSI) are two competitive options to be used as an interfacing unit between variable dc input resource and ac output fed into on-grid, off-grid and industrial used. Among the two topologies, VSI is widely used due to its variable controllable output voltage and ability to operate steadily with open loop V/Hz control. Yet, it suffers circuit complexity due to the need of extra converter stage to meet the required output. On the other hand, CSI has an advantage of voltage boosting capability and better quality of output waveshape, thus no extra converter stage is needed. Most of research works were focusing on studying the suitability and practicality of CSI, along with the advancement using silicon carbide-based power switches and improved modulation techniques to minimize the harmonics suffer by CSI. There is lack of research in investigating the boosting capability particularly on how high CSI able to boost the fundamental output and its impact to overall performance in both open and closedloop standalone system. Thus, this work is intended to highlight in detail the boosting capability of CSI and compare with VSI based on the several circuity and operational features. To support the work, three modulators are implemented namely sinusoidal pulse width modulation (SPWM), third harmonic injection PWM (THIPWM) and space vector modulation (SVM). A dedicated synchronous frame proportional-integral (PI) control in used in closed-loop condition. Result shows that CSI topology able to boost the fundamental output voltage by 52% to 58% by using smaller modulation index as compared to VSI. Interestingly, CSI able to achieve comparable quality and harmonic minimization of output voltage and current as in VSI but with smaller PI control gain. All works are analyzed and verified using MATLAB/Simulink platform.

Power losses reduction in a variable linear power supply using the LM317 voltage regulator

In this work, the design and development of a new variable linear power supply, using the LM317 regulator, is proposed. The originality of this power supply is related with the control of the rectifier circuit, which is based on a reference of voltage, superimposed on the output voltage. This reference is used in the control strategy to maintain a constant voltage between the input and the output voltages of the LM317 regulator. Due to this strategy, the heating losses are greatly reduced, allowing to increase the efficiency of the regulator to about 90%, and to reduce the requirements of the cooling system. Moreover, drawbacks of conventional power supplies are mitigated, where the developed variable linear power supply delivers a current of 3 A and a variable output voltage, from 1.2 V to 30 V. The LM317 regulator was modeled by its thermal equivalent structure associated with a heatsink to study the heat transfer problem. The modeling was performed on the Matlab Simulink software, and the theoretical results were validated by a set of experimental tests using the LM317 regulator.

Enhanced output performance of sandwich-type ZnO piezoelectric nanogenerator with adhesive carbon tape

In this paper, we present a highly durable and energy-efficient sandwich-type zinc oxide (ZnO) piezoelectric energy harvesting nanogenerator, consisting of symmetrically stacked layers of ZnO/carbon tape/ZnO (ZCZ). The sandwich-type ZnO/carbon tape/ZnO nanogenerator (ZCZ-NG) devices were fabricated in a cost-effective way by depositing ZnO layers on indium tin oxide (ITO)-coated polyethylene naphthalate (PEN) substrates in a radio frequency (RF) magnetron sputtering system to form ZnO/ITO/PEN-stacked blocks as well as using a conductive double-sided adhesive carbon tape to bond two ZnO/ITO/PEN blocks together, appreciably reducing the overall fabrication time and processing steps. The output voltage and current of the fabricated ZCZ-NG devices were measured for various bending strain rates, device sizes and thicknesses of ZnO layers, generating up to about 30 V in terms of the peak-to-peak output voltage, which is much higher than those of other similar sandwich-type piezoelectric nanogenerators we reported earlier. Moreover, the output voltage variations of various ZCZ-NG devices due to their ZnO thicknesses, bending strain rates and device sizes were investigated through the observation of their output voltages.

Design and Economic Evaluation of Low Voltage DC Microgrid based on Hydrogen Storage

ABSTRACT This study provides designing and techno-economic analysis of a low voltage (48 V) DC microgrid for domestic load application. In present DC microgrid, photovoltaic (PV) is considered as main power generator to deliver the load demand while fuel cell (FC) and battery are considered as backup power sources. To establish a 48 V DC bus, suitable DC-DC converter having wide input voltage range (22–65 V) is designed to stabilize the variable output voltage of PV and FC generators. The converter efficiency was found to be ≈ 87%. A techno-economic study is also carried out to assess the levelized cost of electricity in microgrid using different energy storage systems, i.e. battery and hydrogen. Lead-acid and lithium-ion are considered as battery storages while high-pressure cylinder and metal hydride storages are considered for hydrogen storage. It is found that PV-battery is most economical configuration; however, PV-FC-battery is better choice for high reliability of overall system. PV-FC-battery configuration has lower cost of electricity as compared to PV-FC alone system. In battery storage system, lithium-ion battery shows faster charging/discharging and efficient operation as compared to lead-acid battery application. In hydrogen storage system, if high-pressure hydrogen is considered, the levelized cost of electricity is reduced significantly as compared to metal hydride storage. However, metal hydride is much better choice for hydrogen storage as compared to the high pressure considering the safety concern.

Sistem Kendali Intensitas Cahaya Lampu Penerangan Jalan Umum Menggunakan Transformator Variabel Berbasis Arduino Uno

This research discusses the Arduino Uno based public street lighting intensity control system. The street lighting technology applied so far is still conventional technology that is classified as wasteful of energy because it still uses a continuous lighting system or an On-Off system. PJU problems arise because of too much power consumption caused by the use of large power lamps and lamp operating times. This research utilizes Arduino Uno and RTC to control the value of the variable voltage output transformer based on time division. This system has been able to control the voltage of 400 watt sodium lamps. The output voltage of the transformer has been divided into three levels, namely level 1, level 2 and level 3. The division of this level is based on the operating time of the lights, namely level 1 at 1830 WIB to 2200 WIB, level 2 at 2201 WIB until 2359 WIB, level 3 at 0000 WIB until 0530 WIB. Transformer output voltage at level 1 can be 220 volts. The output voltage of the transformer at level 2 can be 210 volts. Transformer output voltage at level 3 can be 200 volts. The intensity of the 400 watt sodium lamp light at level 1 is an average of 99.9 lux. The intensity of the 400 watt sodium lamp light at level 2 is an average of 85.45 lux. The intensity of the 400 watt sodium lamp light at level 3 is an average of 78.6 lux.

Dual‐output AC–DC converter with three‐port bridgeless PFC and non‐isolated DCX

This study proposed a dual-output AC–DC converter based on three-port bridgeless power factor corrector (TPB-PFC) and a non-isolated resonant DC-transformer (Ni-DCX) for dual-output DC voltage applications. A constant DC output voltage and a variable DC output voltage are provided simultaneously by the proposed AC–DC converter. Based on the TPB-PFC converter, a stacked power conversion structure with reduced power conversion stage is presented. Therefore, lower power losses and higher efficiencies are achieved. Meanwhile, soft switching of all the power devices in the Ni-DCX is achieved with open-loop controlled and optimised operation of the Ni-DCX, resulting in easy control and higher efficiency. In addition, switching losses of the TPB-PFC are reduced thanks to the three-level characteristic. Operation principles and characteristics of both TPB-PFC and Ni-DCX converter, and modulation and control strategies of the proposed AC–DC converter are analysed in detail. Feasibility and effectiveness of the proposed solutions are verified experimentally with a 2 kW dual-output AC–DC prototype.

Uncertainty analysis and robust control of fuel delivery systems considering nitrogen crossover phenomenon

In this paper, the fuel delivery subsystem (FDS) with hydrogen recirculation and anode bleeding is applied in proton exchange membrane fuel cell (PEMFC) system, which is utilized to supply hydrogen to the anode of stack and recirculate fuel back to the supply line. As the diffusion of nitrogen from cathode to anode is inevitable in a real PEMFC during long-term operation. To prevent system performance decline due to nitrogen accumulation. Therefore, this paper firstly develops a control-oriented nonlinear dynamic FDS model involving gas diffusion. Additionally, the FDS is very sensitive to operating environment, uncontrolled operation conditions may cause stack degradation. Specifically, a method based on Monte Carlo simulation is proposed to identify the key parameter boundaries. Then the gas distribution in FDS due to nitrogen crossover is analyzed in detail. After this, a hybrid robust methodology based on sliding mode algorithm is also proposed to maintain adequate hydrogen pressure supply, suitable hydrogen and nitrogen content in the system in presence of nitrogen crossover and renewed uncertainties. Finally, the performance of the presented controller is compared with nonlinear PID (NPID) control and nonlinear multi-input-multi-output (NMIMO) control through a hardware-in-the-loop test bench. Experimental results show that the hybrid controller is accurate and suitable for control purpose, the nitrogen content is restricted to the given range and the variation of output voltage is limited to the desired boundaries, the feasibility and effectiveness are validated.

High Efficiency Buck-Boost Converter with Three Modes Selection for HV Applications using 0.18 μm Technology

In this paper, we aim to make a detailed study on the evaluation and the characteristics of the non-inverting buck–boost converter. In order to improve the behaviour of the buck-boost converter for the three operating modes, we propose an architecture based on peak current-control. Using a three modes selection circuit and a soft start circuit, this converter is able to expand the power conversion efficiency and reduce inrush current at the feedback loop. The proposed converter is designed to operate with a variable output voltage. In addition, we use LDMOS transistors with low on-resistance, which are adequate for HV applications. The obtained results show that the proposed buck-boost converter perform perfectly compared to others architecture and it is successfully implemented using 0.18 μm CMOS TSMC technology, with an output voltage regulated to 12V and input voltage range of 4-20 V. The power conversion efficiency for the three operating modes buck, boost and buck-boost are 97.6%, 96.3% and 95.5% respectively at load current of 4A.

Analytical investigation of an energy harvesting shape memory alloy–piezoelectric beam

This work presents an analytical investigation of a cantilever shape memory alloy (SMA)/piezoelectric laminated composite beam subjected to a tip load with possible temperature variation. The beam consists of two piezoelectric layers of identical thickness bonded to a superelastic SMA core exhibiting asymmetric tensile–compressive behavior. Two loading scenarios are considered where either the temperature of the beam or the applied tip load is varied, while the other parameter is fixed. In each case, the load results in deformation of the SMA core and the piezoelectric layers bonded thereto, leading to the generation of an electric charge. The deformation of the SMA material is modeled based on an extended version of the ZM constitutive relations for SMAs that accounts for intrinsic tensile–compressive asymmetry. Geometric and force equilibrium considerations are used to identify the correct sequence in which different solid-phase structures develop within the superelastic core during a complete loading–unloading process. Temperature-dependent moment and shear force equations are then derived and used in investigating the electrical and mechanical properties of the beam. The proposed model is validated against 3D finite element simulations, and the general trend of output voltage variation with temperature is shown to be consistent with experimental data.

Multiple-Loop Control Design for a Single-Stage PV-Fed Grid-Tied Differential Boost Inverter

This paper focuses on the control design of a differential boost inverter when used in single-stage grid-tied PV systems. The inverter performs both Maximum Power Point Tracking (MPPT) at the DC side and Power Factor Correction at the AC side. At first, the state-space time-domain averaged model of the inverter is derived and the small signal frequency domain model is obtained using a quasi-static approximation in which the inverter is treated as a DC–DC converter with a slowly varying output voltage. Then, the controllers are designed using a three-loop strategy in which the inverter inductor currents loop is used for suitable compensation, the DC Photovoltaic (PV) voltage loop is used for MPPT and the output grid current loop is used for Power Factor Correction (PFC) and active power control. The selection of the control parameters is based on a compromise among suitable system performances such as settling time of the input PV voltage, the sampling period of the MPPT, total harmonic distortion of the output grid current, power factor as well as suppression of subharmonic oscillation for all the range of the operating duty cycle. The resulting design ensures that the oscillations of the voltage, current and power at the DC side and the grid current at the AC side are effectively controlled. The validity of the proposed control design is verified by numerical simulations performed on the switched model of the system demonstrating its robustness and fast response under irradiance variations and MPPT perturbations despite the nonlinearity and complexity of the system.

Analysis of the Impact of Wire Resistance on Nano-scale Memristor Crossbar Array Implementing Perceptron Neural Network

In this work, the impact of wire resistance in pure memristor crossbar array is mathematically analysed and verified by the circuit simulation. The memristor crossbar without CMOS device is utilized for application of character image recognition, in which wire resistance is presented. Memristor crossbar circuit is analysed separately with respect to wire resistance on vertical line and wire resistance on horizontal line. The result shows that wire resistance on vertical line can be eliminated because they can be self-compensated. The simulation result agrees with the analysis. The variation of output voltage caused by wire resistance less affect the recognition rate of memristor circuit. On the other hand, when wire resistance on horizontal line is assumed to be 2.5Ω. The output voltages are varied remarkably. Such variation of output voltage degrades the recognition rate of memristor crossbar circuit. The interesting phenomenon is also investigated. The column that is close to the first column has less variation of output voltage, whereas the one that is far from the first column has much variation of output voltage. The result can be used in improving the memristor crossbar architecture, which can tolerate the impact of wire resistance. For example, if we want to increase the size of crossbar, we should increase the number of rows, rather than the number of columns.

Design-oriented fast response voltage mode buck converter with adaptive ramp control

This paper proposes a new adaptive ramp voltage mode control scheme. Instead of using the conventional slow compensation path of the voltage mode, the proposed scheme adds an extra feedback path to adjust the amplitude and DC-offset of the ramp signal and to directly accelerate the duty cycle according to the output voltage variation. In addition, a design-oriented analytical method is adopted to intuitively analyzes the loop characteristics and provides accurate instructions for the implementation and optimization of the compensator. A 5–1 V buck converter is implemented in the proposed adaptive ramp control scheme with optimized compensation. Simulation and measurement results show that the converter achieves a bandwidth of up to 591 kHz with a 3 MHz switching frequency and a 65° phase margin. In addition, the undershoot voltage and the recovery time are 16 mV and 19 μs with a load change from 0.5 to 1 A. The proposed control scheme shows superior transient response performance while maintaining fixed frequency operations with a simple system structure.

A Fast-Transient Response Digital Low-Dropout Regulator With Dual-Modes Tuning Technique

A fast transient response digital low dropout (LDO) regulator with a low quiescent current is proposed for power management applications in a self-powered wireless sensor system. The digital LDO incorporates both bisection method (BM) and steady-state tuning techniques to enhance the current efficiency and transient response speed. In steady-state period, the digital LDO works at steady-state mode and only one PMOS is switched at each clock edge for high accuracy and current efficiency. Once the variation of output voltage exceeds the detection boundaries, the BM mode is triggered and the required array conductance can be found in a short response time. The proposed digital LDO is fabricated using 65nm CMOS process. The measurement results show that with the load current switching between 0.1 mA and 4.5 mA, the proposed digital LDO shows a transient response time of 5.9 μs with a maximum undershoot voltage of 118 mV at a regulated output voltage of 0.55V. The current efficiency is 99.7% and the figure of merit is 62.2 ps.

Improving the Stability of R2R Printed 1‐Bit Code Generator through Spin‐Coated Multilayer‐Encapsulation Method

AbstractRoll‐to‐roll (R2R) printed electronic devices have great advantages for developing large scale flexible and disposable devices when compared to current Si‐based technology. For practical realization of these advantages, however, R2R printed devices need to surmount device functionality limitations, most urgently high‐power dissipation and poor device stability. To resolve both imperative challenges at once, herein, an all R2R printed complementary metal‐oxide‐semiconductor (CMOS) 1‐bit code generator with spin‐coated multilayer encapsulation method is developed. In order to print CMOS devices by an all‐R2R gravure printing method, electrical amphoteric property of the single walled carbon nanotube (SWCNT) is utilized to fabricate both p‐type and n‐type SWCNT based thin film transistors (TFTs). In addition, printable encapsulating polymeric materials (CYTOP and FG‐3650) are developed to effectively prevent H2O permeation. The resulting CMOS 1‐bit code generator is able to continuously operate for 2 h under ambient conditions without any variation in output voltage and frequency.

Implementation of dead beat controller using Particle Swarm Optimization for software defined network

Renewable energy sources is largely adopted for generation of electrical energy and various methodologies have been proposed in this area This paper focuses on analysis, design and implementation of DC/DC buck–boost converter towards producing the hybrid prototype, consisting of 3kW PV and 3.2 kW PMSG using wind energy conversion system. Particle Swarm Optimization algorithm is employed for regulation of the output voltage generated. To extract maximum power, PSO algorithm is adopted for hybrid renewable energy sources which are considered as NP hard problem. To eliminate the harmonics and to have maximum electrical power delivered to the grid on polynomial time, the single phase or three phase sinusoidal pulse width modulation (SPWM) inverter has been employed with PQ control strategy using metaheuristic based approximation. The proposed PSO technique produces a steady state DC link voltage of 400 V with reduced harmonic distortion using LC filter. Further, the application of capacitor bank arrangement reduces the ripples present in the output voltage variations. The simulation outcomes prove the efficiency of the proposed model along its measurements.

Shunt Regulator for the Serial Powering of the ATLAS CMOS Pixel Detector Modules

A shunt regulator was designed to meet the specifications for the serial powering of the CMOS pixel detector modules in compatibility with the next upgrade of the ATLAS detector. Serial powering greatly increases the system’s power efficiency when compared to a parallel powering scheme and allows for significant material budget savings in the power cabling. In such a scheme, each pixel detector chip is powered by a shunt regulator that takes in a constant current and produces a regulated output voltage relative to the module’s potential ground. The proposed regulator has a modular structure. Each regulator module consists of a shunt regulation submodule followed by a low-dropout voltage regulation submodule and is designed to deliver a nominal output current of 10 mA. The regulator module’s schematic is presented along with a theoretical study and stability analysis. A test chip was designed in the 0.18- $\mu \text{m}$ CMOS technology containing one main shunt regulator composed of 126 modules, as well as two separate regulators each composed of one single module. The characterization measurements show a correct dc startup for various load conditions, as expected by simulations. The output voltage of a single module is regulated with a precision $\text{m}\Omega $ , including the wire bonding and test bench parasitics. The test chip is successfully tested in the serial mode and in the parallel mode. In the latter mode, the current mismatch between the parallel chips is measured to be less than 3.4% for an input current of 1 A. Moreover, transient measurements performed with an active load show proper functioning with no undershoots or overshoots. Finally, the test chip was irradiated with an X-ray source up to 125 Mrad. Measurements show a stable response of the regulator with an intrinsic output voltage variation of less than 1%.

Different Effect of Sliding Mode Controller on DC-DC Boost Converter with Output Voltage Variation Analysis

Different Effect of Sliding Mode Controller on DC-DC Boost Converter with Output Voltage Variation Analysis

Analysis of double chambered single and cascaded microbial fuel cells: characterisation study based on the enrichment of fuel

Need for green energy, depletion of fossil fuels becomes the immediate requirement for building a clean and sustainable society. Among the various sustainable energy sources, microbial fuel cell is an emerging field with vast history as it converts the naturally available materials or bio-products into electricity with the help of microbes. Hence microbial fuel cell is an energy transducer. The experimental set-up is a double chambered microbial fuel cell with four single units among which two are separate and other two single units are cascaded into one. Cow dung and sheep worm kept in the anodic chamber are used both individually and also in combination. In order to make a complete characterisation study of MFC, additives like vermicompost, curd, etc., are added and they help to promote the growth of bacteria into it. This experimental setup, clearly defines the variation of output voltage and output power for the three different samples chosen with respect to time. Also the characterisation study is made based on the implementation of MFC set up with respect to the fuel enrichment and its performance is analysed.

A Portable Microwave Interferometry Sensor for Permittivity Detection Based on CCMRC

A portable microwave complex permittivity sensor based on the interferometry configuration is proposed. A complementary compact microstrip resonant cell (CCMRC) is applied as the sensitive element, which converts the dielectric information of the material under test (MUT) into the phase variations of its transmission coefficient. A miniaturized interferometry platform based on a down-converting mixer further translates the phase change into DC output voltage variation, which can be readily recorded with a direct readout circuit. In this context, expensive and bulky vector network analyzer is no longer needed, thereby leading to a low hardware cost. With comprehensive theoretical analysis, the material permittivity is simply extracted using a specific extrapolation algorithm. As a proof of concept, several different solid material samples with known permittivity values are used to verify the devised detection system.

Global sensitivity analysis of solid oxide fuel cells with Bayesian sparse polynomial chaos expansions

Uncertainties that commonly exist in mathematical models prevent accurate predictions of solid oxide fuel cell performances and consequently impede the development and application of solid oxide fuel cell technologies. Assessing the impact of uncertain input parameters on cell performance variability is of utmost importance to the improvement of fuel cell models. To this end, a global sensitivity analysis is performed on the electrochemical model of a fuel cell using the Bayesian sparse polynomial chaos expansion approach. With this approach, machine-learning models are constructed to approximate the input-output relationship of the electrochemical model. The first-order, second-order, and total Sobol’ indices are then computed analytically to quantify the individual impact of each parameter, the pairwise interaction between them and the total coupling effects over the entire input parameter space. These sensitivity indices show that the kinetic parameters of the electrochemical reaction, such as the activation energy, pre-exponential coefficients, and the electronic transfer coefficient, are the most sensitive parameters that significantly contribute to the variation of cell output voltage, which indicates the requirement for in-depth investigations of these parameters to enhance the accuracy in fuel cell model predictions. This work uncovers the possibility to apply data science techniques to the field of fuel cells. The results of this study not only demonstrate the effectiveness of the Bayesian approach for performing sensitivity analysis on the electrochemical model of a fuel cell, but also shed light on the rational design and optimization of solid oxide fuel cells.