Power Supply Applications Research Articles

Optimized array for powering sensors: Thermal and electromagnetic energy harvesting and fusion

Environmental energy harvesting technology has achieved great success in remote sensor power supply applications. However, existing technologies in the power grid neglect the potential of weak energy sources. This study aims to optimize the most reasonable array configurations and create hybrid energy fusion schemes for different weak energy environments. Taking thermal and electromagnetic energy harvesting from cable surfaces and currents in coaxial cables as an example, this paper introduces a genetic algorithm-based optimization method of harvester array configuration under multiple constraints and a dual-source energy fusion system. First, a vector impedance parameter identification method based on the equivalent circuit model of current transformer (CT) is proposed. Later, an optimization model for harvester array is established. Then, a genetic algorithm is used to optimize array combinations. And, a dual-source energy fusion system is proposed. Finally, thermal and electromagnetic energy harvesting and fusion are performed using 3 × 1 TEGs array and 6 × 1CT array. Under the specified conditions of a hot end temperature of 50 ℃ and an effective current value of 2 A, the power supply for the Zigbee wireless sensing system is realized to monitor the temperature of the cable core.

Energy Management Considering both Efficiency Optimization and Lifetime Balance of Multi-stack FCS

Abstract With the increase of energy transformation and environmental protection awarenesses, fuel cells, as a clean and efficient energy conversion technology, have been widely adopted in transportation and stationary power supply applications. A single fuel cell has a limited power capability. On the other hand, the multiple fuel cells are combined into a multi-stack fuel cell system (MFCS), which provides a high power output and modular design. However, the energy management of such multi-stack systems faces challenges such as uneven power distribution, inconsistent stack life, and low overall efficiency. Current multi-stack fuel cell control systems often optimize single objectives, either efficiency or lifetime balance produce the optimized energy management strategy. This may not suffice for the overall system benefit. For example, if only efficiency is optimized by energy management, the failure to consider lifetime balance may result in uneven life degradation for each fuel cell, and vice versa. To address the above issues, this paper proposes an energy management strategy for multi-stack fuel cell systems that considers dual objectives, which can simultaneously ensure the optimal co-optimization of the output efficiency and stack life for each stack, thereby improving the overall operating efficiency and lifetime of the system. The effectiveness and practicality of the proposed energy management control strategy were verified on a 60kW dual-stack PEMFC fixed power generation system developed by SeeEx.

A remarkable permeability enhancement of Ni1−xZnxFe2O4 (x = 0.65 and 0.70), using a multi-compound calcined additive

In this study, entanglement of composition, additive and/or sintering conditions and their effects on magnetic properties of soft ferrites, nickel zinc spinel ferrites (Ni1−xZnxFe2O4, x = 0.65 and 0.70) which were prepared via conventional solid-state reaction method investigated. Also an equiponderant calcined mixture of Bi2O3, CaO, CeO2, SiO2, Al2O3, Y2O3 and nanotitania was mixed thoroughly and used as a multi-compound calcined additive (MCCA). Calcined ferrite powders were crushed, dry and wet milled, dried, mixed with different amounts of MCCA (0.0, 0.5, 1.0, 1.5 and 2.0 wt%), formed in toroidal shapes and finally sintered at different temperatures, from 1150 up to 1360 °C for 3 h. X-ray diffraction assessment confirmed formation of the single phase cubic spinel structures. Initial permeability and Q-factor spectra of the toroids were obtained from 0.1 to 1000 kHz, using an LCR meter. The results show that initial permeability of each sample has a maximum and addition of MCCA to the ferrites leads to a marvelous increase in permeabilities. Additionally, MCCA decreases the optimum sintering temperature too. The optimum amounts of additive were 1.0 and 0.5 wt% for the x = 0.65 (μ′ = 492, Ts = 1280 °C) and x = 0.70 (μ′ = 478, Ts = 1320 °C), respectively. Permeability spectra illustrate that utility zone of the Ni0.35Zn0.65Fe2O4 and Ni0.3Zn0.7Fe2O4 are both less than 100 and 10 kHz, respectively. The results represent that there is a strong entanglement between composition, additive and/or sintering conditions. It can be concluded the MCCA added Ni0.35Zn0.65Fe2O4, is suitable for application in the switching power supplies.

Droplet-Based Direct-Current Electricity Generation Induced by Dynamic Electric Double Layers.

Harvesting energy from water droplets has received tremendous attention due to the pursuit of sustainable and green energy resources. The droplet-based electricity generator (DEG) provides an admirable strategy to harvest energy from droplets into electricity. However, most of the DEGs merely generate electricity of alternating current (AC) output rather than direct current (DC) without the utilization of rectifiers, impeding its practical applications in energy storage and power supply. Here, a direct current droplet-based electricity generator (DC-DEG) is developed by the simple configuration of the electrodes. The DC output originates from the dynamical electric double layer (EDL) formed at two electrodes and droplet interfaces where the charging/discharging process of EDL capacitance occurs. Several experiments are exhibited to demonstrate the rationality of the proposed principle. The influence of some factors on the output is investigated for further insight into the DC-DEG device. This work provides a novel strategy to harvest energy from water droplets directly into DC electricity and may expand the application of DEGs in powering electronic devices without the help of rectifiers.

Design and Implementation of GaN-Based Two Switch Flyback With Synchronous Rectification for New Space Applications

This article presents a comprehensive investigation and implementation of a continuous conduction mode pulse width modulated two-switch DC/DC flyback converter utilizing Gallium Nitride Field Effect Transistors (GaNFETs) for New Space applications. The New Space concept advocates for the integration of Commercial Off-The-Shelf (COTS) materials in the space industry. The approach offers cost-effective solutions and reduces lead time for space designs. The study provides steady-state analysis and design considerations for two switch flyback converters, highlighting the transformative capabilities of GaNFETs, especially in high-frequency operations. The rationale behind the preference for GaNFETs over MOSFETs in satellite power supply applications and the strategic benefits of COTS materials are explained in detail. In addition, the synchronous rectification method is implemented to obtain better efficiency, particularly for high-output current operations. The converter achieves an efficiency of over 87% when the load exceeds 50%, with varying input voltages from 20 V to 40 V and a switching frequency of 300 kHz. The experimental findings show that the designed converter can serve as a high efficiency and reliable satellite power converter.

Advanced Electrospinning Technology Applied to Polymer-Based Sensors in Energy and Environmental Applications.

Due to its designable nanostructure and simple and inexpensive preparation process, electrospun nanofibers have important applications in energy collection, wearable sports health detection, environmental pollutant detection, pollutant filtration and degradation, and other fields. In recent years, a series of polymer-based fiber materials have been prepared using this method, and detailed research and discussion have been conducted on the material structure and performance factors. This article summarizes the effects of preparation parameters, environmental factors, a combination of other methods, and surface modification of electrospinning on the properties of composite nanofibers. Meanwhile, the effects of different collection devices and electrospinning preparation parameters on material properties were compared. Subsequently, it summarized the material structure design and specific applications in wearable device power supply, energy collection, environmental pollutant sensing, air quality detection, air pollution particle filtration, and environmental pollutant degradation. We aim to review the latest developments in electrospinning applications to inspire new energy collection, detection, and pollutant treatment equipment, and achieve the commercial promotion of polymer fibers in the fields of energy and environment. Finally, we have identified some unresolved issues in the detection and treatment of environmental issues with electrospun polymer fibers and proposed some suggestions and new ideas for these issues.

Stacked bidirectional DC‐DC converter based on classical boost/buck converter for uninterruptible power supply applications

SummaryIn this paper, a new stacked bidirectional non‐isolated DC‐DC converter for uninterruptible power supply applications is presented. It is a stacked adaptation of the classical bidirectional boost/buck converter and presents improvements such as low number of components; low voltage and current stress on components; high efficiency; and simplicity of operation. In addition, in this paper, the modeling and control of the proposed converter are done, and a comparative evaluation among proposed converter with similar topologies is evaluated. A prototype of 1 kW, 144 to 400 V, is developed in laboratory to validate the theoretical evaluations of proposed converter. Besides that, the proposed converter is also evaluated under different dynamic condition, which illustrates the effectiveness of the converter. Finally, the maximum efficiency obtained is 96.38% in step‐up mode and 95.7% in step‐down mode.

Reflective vortex focusing for acoustic contact-free object rotation

The use of acoustic vortex waves with angular momentum is a promising means of transferring mechanical torque to an object without making any physical contact. However, the existing passive-conversion vortex lenses are unable to produce strong acoustic radiation torque. To address this issue, we propose a flat reflector sculpted by spiral grooves. It reflects and converts incident waves into vortex-focusing waves that generate radiation torque. Compared with a transmission-type lens, a reflection-type vortex focusing plate exhibits superior functionality in converging sound waves and creating a stronger circular intensity flow. In this work, we analyze the vortex-focusing sound by Rayleigh-Sommerfeld integral theory and boundary element simulation, confirmed by experiments. The number, depth and direction of spiral grooves determine the topological charge, focusing intensity and torque direction, respectively. We evaluate the local and total acoustic radiation forces and torques, acting on small and large fixed spherical targets in the vortex-focusing beam. As a result, spinning a centimeter-size origami pinwheel several times larger than the wavelength at 40 kHz is realized without direct contact, by utilizing the enhanced acoustic radiation torque converged by the reflector. This technology enables efficient convergence of acoustic waves and simultaneous contactless transfer of mechanical torque to an object, thereby presenting potential applications in sound energy harvesting and wireless power supplies.

Optimal Parameter Identification of Energy Harvesters Using Vector Impedance Quantum Genetic Algorithm: A Case Study With Current Transformer

Energy harvesting technology, as an emerging energy technology, has contributed outstandingly to the application of online monitoring sensors in power systems. The accurate parameter identification of the harvesters is crucial for their power supply applications. This work aims to investigate the parameter identification of harvesters with complex equivalent circuit models, here taking a current transformer as an example. However, previous studies focused on optimizing algorithms rather than data sources. This paper demonstrates a vector impedance quantum genetic algorithm (QGA) parameter identification method to identify the amplitude and phase information of the impedance responses. By comparing the results of the proposed method with the genetic algorithm and PSO based on impedance responses and QGA based on load resistance responses, it is proved that the proposed vector impedance QGA identification method is optimal in terms of accuracy, speed, and robustness. The root mean square errors of the output voltage and the phase difference with the primary current for the proposed method are 5.884 × 10−5 V and 4.473 × 10−4 ms. Moreover, the practical applicability of this method is validated, demonstrating its effectiveness in real‐life and industrial settings. The proposed identification method in this paper changes the source data so that the sample data are small in volume and extensive in information, which enables faster and more accurate parameter identification. This study provides a new idea for parameter identification researches.

Single Phase Sine-Wave Inverter with High DC Bus Utilization Using Natural Compensation

Abstract- In this paper, a new fixed frequency single phase sine-wave inverter topology - having high DC bus utilization - is presented. The main inverter uses six IGBT switches operating at low frequency in over-modulation mode to create a five-level voltage waveform; thus, having low switching losses with high DC bus utilization. A series active power filter (SAPF) using power MOSFETs helps to remove the major harmonic voltages. No isolated DC power supply is required across the SAPF that works on a simple feed-forward compensation (instead of feedback), based on the principle of natural compensation. The DC bus voltage needed for the SAPF is about half of the inverter, thus the SAPF has low switching loss even at the designated switching frequency. The switching frequency components of the SAPF remain in the output as they are not compensated, necessitating the use of a small filter at the output to attenuate them, to create a low total harmonic distortion output voltage with higher fundamental compared to the conventional schemes using Sinusoidal Pulse Width Modulation. The proposed inverter is suitable for fixed frequency backup power supply or other applications like renewable energy connection to the power grid.

Polypyrrole in-situ polymerized MXene/TPU fiber electrode for flexible supercapacitors

Ti3C2Tx-based flexible fibers have great potential and wide applications in the energy storage field of wearable electronic textiles and portable electronic devices. This work reports a Ti3C2Tx-MXene/TPU/polypyrrole(PPy) fiber in which PPy is grown on the surface of Ti3C2Tx/TPU fiber by in-situ polymerization. Through efficient wet spinning and in-situ polymerization, Ti3C2Tx/TPU/PPy fiber exhibit pore structure and abundant active sites, which significantly enhance charge transfer rate and conductivity. The fiber exhibits a capacitance of 41.2 F g−1(5 mV S−1) and excellent rate performance in 1 M H2SO4 electrolyte. Its symmetrical fiber-based flexible supercapacitors(SCs) can provide an energy density of 2.36 mW h g−1. At the same time, the fiber has good flexibility and can be woven into a fabric SCs as a wearable energy storage device to realize power supply applications such as electronic watches and LEDs, which provides a potential strategy for the application of flexible wearable energy storage devices.

Methodology for Assessing Power Needs for Onshore Power Supply in Maritime Ports

Maritime ports represent an important ecosystem for pollutant emissions and, considering the ongoing energy transition, need to adopt new solutions to mitigate current emission levels. These emissions are partially avoidable if ships and vessels docked at the port use electric energy to feed their power needs instead of using their internal combustion engines. In Europe, there is an ongoing discussion on including such emissions in the European Union Emissions Trading System, which will represent added costs for maritime operators. Onshore power supply systems can contribute to the ongoing energy transition by allowing the use of electric power to feed docked ships. As a first step to contribute to the development of onshore power supply solutions, it is necessary to evaluate the added power needs that these systems would represent for the port. This paper presents a methodology that allows port operators to verify, straightforwardly and transparently, their power needs for onshore power supply applications. The methodology is based on the historical data of docked ships at the port or quay level and provides an energy analysis of each type of vessel to determine the power to be installed at the port so that it is possible to supply energy to different types of ships and vessels simultaneously. Additionally, the implemented methodology provides economic and technical decision support factors by comparing the fuel costs with electric power costs, assessing the potential for this transition to onshore power supply. The methodology is validated using a real case study for the Port of Lisbon, and obtained results demonstrate the potential for the installation of an onshore power supply in medium- to large-dimension maritime ports.

Controlled power supplies applications in radar transmitters

Controlled power supplies applications in radar transmitters

Nanosheets array-induced nanofluidic channels toward efficient primary batteries-coordinated textiles

Flexible hygroelectric generators (HEGs) that derive affordable and sustainable electricity power from omnipresent moisture are promising candidates for smart textile electronics. However, the desired compatibility of high output current and continuous operating voltage is still challenging for wearable HEGs to meet the ever-increasing nanotechnological requirements. Herein, we rationally design and finely synthesize conductive carbonized silk fabrics with in situ growth of SnO/SnO2 nanosheet arrays, which are successfully employed to fabricate high-efficiency wearable HEGs with a maximal power density of 26.66 μW·cm−2 by sandwiching with MXene/cotton fabrics and Al electrodes. Impressively, the vertically interlaced SnO/SnO2 nanosheet arrays supply abundant nanofluidic channels for rapid water diffusive flow with a high flow potential. Combined with the excellent moisture absorption and retention of MXene/cotton textiles, these prepared HEGs process sustained voltage and current outputs of 0.932 V and 0.434 mA over 20,000 s. These flexible HEGs are capable of application in self-powered sensors and micro power supplies, delivering a fresh strategy for the rational design of high-performance and sustainable textile-based electronics.

An improved Buck converter with high frequency and high step‐down ratio for auxiliary power supply applications

AbstractBuck converter is a good candidate for the non‐isolated auxiliary power supply (APS) due to its simple structure and high efficiency. However, it can hardly be adopted in applications that required a very high step‐down ratio due to the difficulty to realize an ultra‐low duty cycle, especially when the switching frequency becomes higher and higher. Here, an improved Buck converter is proposed for high‐frequency and high‐step‐down‐ratio APS application. With the control method based on energy extraction, the proposed topology can achieve an ultra‐low equivalent duty cycle. Thus, a high step‐down ratio can be achieved under a high switching frequency. Moreover, the proposed structure can be applied on several types of the main power stage through the power switch sharing technique. Finally, the prototype with the switching frequency of 1 MHz and the step‐down ratio of 18:1 is verified by the experimental results.

Easy-to-install battery storage based residential power supply with contactless power transfer

Solar energy with battery storage has enormous potential for residential power supply applications. However, the installation is often complicated with lots of wiring. The wireless power transfer (WPT) interface can greatly reduce the complicated wiring part, facilitating easier installation, with additional benefits like electrical isolation, lower maintenance cost, better reliability. However, rigorous proof-of-concept of WPT for LV household power supply still remains to be largely unexplored. This work fills the research gap by presenting application of contactless power transfer system with battery storage for the solar-powered low-voltage (LV) power supply. Various resonant topologies for inductive power transfer (IPT) are studied, and a complete theoretical model of an LCL compensated IPT system integrated with a battery energy storage system is presented. The voltage and current characteristics are investigated to understand the operation of the proposed integrated IPT system at LVDC level. The setup is first realized and analysed in details in simulation using MATLAB/Simulink. Hardware experiments proves the feasibility of the contactless power transfer capability at the high efficiency of the integrated IPT battery system. The results show that the proposed system can maintain a constant load voltage of 48 V for a load variation of around 25%, with an efficiency of 92% at 85 kHz switching frequency.

Comparative Study of Passivity, Model Predictive, and Passivity-Based Model Predictive Controllers in Uninterruptible Power Supply Applications

Voltage source converters are widely used in distributed generation (DG) and uninterruptible power supply (UPS) applications. This paper aims to find the controller that performs best when model changes occur in the system, showing insensitivity to parameter variations. A comparison of the finite control set model predictive controller (FCS-MPC), interconnection and damping assignment passivity-based controller (IDA-PBC), and passivity-based model predictive control (PB-MPC) reveals that the PB-MPC provides high resistance to these unexpected LC filter changes in the converter. The second aim of the paper is to reduce the total harmonic distortion (THD) of the output voltage of the three-phase voltage source inverter (VSI). A high total harmonic distortion (THD) value exists in the voltage waveform of the three-phase voltage source inverter (VSI), feeding a non-linear load. A MATLAB simulation was performed using three control techniques for a three-phase VSI feeding: linear load, unbalanced load, and non-linear load. The PB-MPC performs better than the FCS-MPC and IDA-PBC in terms of having a low THD value in the output voltage of the converter under all types of applied loads, improving the THD by up to 30%, and having low variation in THD with mismatched filter parameters, as shown in the bar charts in the results section. Overall, the PB-MPC controller improves the robustness under parameter mismatch and reduces the computational burden. PB-MPC reduces the THD value because it integrates power shaping and the injection of damping resistances into the VSI.

Fractional-Order Model-Free Predictive Control for Voltage Source Inverters

Currently, a two-level voltage source inverter (2L-VSI) is regarded as the cornerstone of modern industrial applications. However, the control of VSIs is a challenging task due to their nonlinear and time-varying nature. This paper proposes employing the fractional-order controller (FOC) to improve the performance of model-free predictive control (MFPC) of the 2L-VSI voltage control in uninterruptible power supply (UPS) applications. In the conventional MFPC based on the ultra-local model (ULM), the unknown variable that includes all the system disturbances is estimated using algebraic identification, which is insufficient to improve the prediction accuracy in the predictive control. The proposed FO-MFPC uses fractional-order proportional-integral control (FOPI) to estimate the unknown function associated with the MFPC. To get the best performance from the FOPI, its parameters are optimally designed using the grey wolf optimization (GWO) approach. The number of iterations of the GWO is 100, while the grey wolf’s number is 20. The proposed GWO algorithm achieves a small fitness function value of approximately 0.156. In addition, the GWO algorithm nearly finds the optimal parameters after 80 iterations for the defined objective function. The performance of the proposed FO-MFPC controller is compared to that of conventional MFPC for the three loading cases and conditions. Using MATLAB simulations, the simulation results indicated the superiority of the proposed FO-MFPC controller over the conventional MFPC in steady state and transient responses. Moreover, the total harmonic distortion (THD) of the output voltage at different sampling times proves the excellent quality of the output voltage with the proposed FO-MFPC controller over the conventional MFPC controller. The results confirm the robustness of the two control systems against parameter mismatches. Additionally, using the TMS320F28379D kit, the experimental verification of the proposed FO-MFPC control strategy is implemented for 2L-VSI on the basis of the Hardware-in-the-Loop (HIL) simulator, demonstrating the applicability and effective performance of our proposed control strategy under realistic circumstances.

Tailor-designed vanadium alloys for hydrogen storage in remote area and movable power supply systems

Vanadium-based alloys are potential materials for hydrogen storage applications in Remote Area Power Supply (RAPS) and Movable Power Supply (MPS). In this study, V80Ti8Cr12 alloys are tailor-made to meet the RAPS and MPS working conditions (293–323 K and 0.2–2 MPa). The effects of pulverization methods and particle sizes on the alloy's hydrogen storage properties have been systematically investigated. In addition, a novel Pressure-Composition-Isotherm approach is employed for the first time to accurately evaluate the hydrogen storage capacities. The reduction of particle size enhances the absorption kinetics due to the increased surface area. However, mechanical pulverization causes lattice distortion that decreases the hydrogen absorption capacity and desorption rate. In contrast, hydrogen embrittlement can effectively pulverize the alloys without generating lattice distortion. The results reveal that 5 mm sample, which is simply subjected to hydrogen embrittlement, achieves the largest usable hydrogen storage capacity up to 2.1 wt% and the fastest hydrogen desorption rate of ∼4 sccm/g that is nine times quicker than required for RAPS and MPS applications. After 500 cycles, the 5 mm alloy retains 90 % of its capacity, demonstrating excellent durability. Hence, 5 mm hydrogen-embrittled V80Ti8Cr12 alloy is an ideal hydrogen storage material in RAPS and MPS systems.

Single-Phase AC-DC-AC Multilevel Five-Leg Converter With High-Frequency Link

This paper investigates a single-phase ac-dc-ac multilevel converter formed by a three-leg module (converter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$a$</tex-math></inline-formula> ) series connected to an H-bridge (converter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$H$</tex-math></inline-formula> ) at the load side of the system to achieve higher and multilevel output voltage. The proposed solution has two dc-links that are connected through a high-frequency link (HFL) formed by an inverter H-bridge, a small toroidal transformer, and a unidirectional rectifier H-bridge. The use of the HFL permits optimizing the SV-PWM strategy by employing vector redundancies that minimize the switching frequency of the devices. Besides, the control system is simplified compared to the conventional solution with floating capacitors. The proposed system is appropriate for uninterrupted power supply and unified power quality conditioner applications. System equations, dc-link voltage specifications, power distribution analysis, and a space vector PWM are discussed. The proposed control strategy ensures suitable load voltage with constant amplitude and fundamental frequency, guaranteeing a high grid power factor and maintaining controlled dc-link voltages. Compared with the conventional solutions, the proposed topology has a lower dc-link voltage rating, lower harmonic content, and lower switching losses in the converters <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$a$</tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$H$</tex-math></inline-formula> . Experimental results are presented to validate the developed studies.