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This article presents three efficient rectifiers for radio frequency energy harvesting (RFEH) systems operating at the fifth generation (5G) band (3.5 GHz). Each rectifier operates at various input power levels (high, low, and across a wide power range). The high and low-power rectifiers feature a single serial topology using HSMS-2860 and SMS-7630 Schottky diodes, respectively, along with microstrip lines to implement the input and output filters and the impedance matching network. At an radio frequency (RF) power level of 15 dBm, the high-power rectifier harvests 67.4% to direct current (DC) power with a 300 Ω load resistor and an output voltage of 2.5 V. The low-power rectifier achieves its maximum power conversion efficiency (PCE) at -2 dBm, reaching 45% efficiency with a 1,200 Ω load. The rectifier with a extended input power range comprises two branches of subrectifiers functioning at both high and low power levels. Depending on the power level, the considered subrectifier harvests radio frequency power into DC power, while the other subrectifier is deactivated. Across a power span of 32.5 dB (ranging from -13 to 19.5 dBm), the rectifier maintains an efficiency above 30%. The proposed rectifiers are efficient and suitable for implementation in 5G-enabled RFEH systems. [ABSTRACT FROM AUTHOR]

This study introduces a novel uninterruptible power supply (UPS) configuration that integrates active power filter (APF) capabilities within a single-phase matrix converter (SPMC) framework. Power disruptions, particularly affecting critical loads, can lead to substantial economic damages. Historically, conventional UPS systems utilized dual separate converters to function as a rectifier and an inverter, without incorporating any power factor correction (PFC) mechanisms. Such configurations suffered from diminished power density, compromised reliability, and spatial limitations. To address these issues, this research proposes an enhanced UPS design that incorporates APF features into the SPMC. The focus of this investigation is on the efficiency of alternating current (AC) to direct current (DC) conversion and the reverse process utilizing this advanced UPS model. The SPMC is selected to supplant the rectifier and inverter units traditionally employed in UPS architectures. A novel integrated switching strategy is formulated to facilitate the operation of the UPS in either rectifier (charging) or inverter (discharging) modes, contingent upon the operational state. The performance and efficacy of the devised circuit design and switching technique are substantiated through simulations conducted in MATLAB/Simulink 2019 and empirical evaluations using a test rig. The findings demonstrate that the voltage generated is sinusoidal and synchronized with the supply current, thereby minimizing the total harmonic distortion (THD) and enhancing both the power factor and the transition efficiency of the UPS system between its charging and discharging states. [ABSTRACT FROM AUTHOR]

In this paper, a CGH40010F GaN-based wideband RF rectifier with high rectification efficiency is presented. A novel continuous class-EFJ-mode rectifier is constructed by combining a continuous class-J-mode rectifier and class-EF-mode rectifier under specific impedance conditions. This novel continuous class-EFJ-mode rectifier has high rectification efficiency and wide bandwidth at the same time. For validation, a wideband high-efficiency class-EFJ-mode rectifier functioning within the 2.0–3.0 GHz range is designed, fabricated, and measured. The measurements indicate that, with an input power of 40 dBm and a resistance of 72 Ω on the dc load, the implemented rectifier sustains a rectification efficiency exceeding 60% across its entire operational frequency band. Meanwhile, the dimensions of the circuits are only 3 cm × 3.1 cm. [ABSTRACT FROM AUTHOR]

A metasurface array for electromagnetic (EM) energy harvesting for Wi-Fi bands is presented in this paper; the metasurface array consists of a metasurface unit, a rectifier, and a load resistor. Each row of unit cells in the array is interconnected to form an energy transfer channel, which enables the transfer and concentration of incident power. Furthermore, at the terminal of the channel, a single series diode rectifier circuit and a load resistor are integrated in a coplanar manner. It is used to rectify the energy in Wi-Fi bands and enables DC energy harvesting across the load. Finally, a 5 × 7 prototype of the metasurface array is fabricated and measured for the verification of the rationality of the design. Testing in an anechoic chamber shows that the prototype achieves a 72% RF-DC efficiency at 5.9 GHz when the available incident power is about 7 dBm. [ABSTRACT FROM AUTHOR]

A watt‐scale dual‐band rectifier with excellent efficiency and a wide input power range is proposed in this letter. The rectifier is composed of two stages. In the first stage, a novel impedance‐matching network with four transmission lines (TLINs) is proposed, which can independently change the input impedance of each band over a large input power range. This approach by deriving closed‐form analytical equations to obtain an exact solution. To test the parameters of the first part of the TLINs in validation and to guarantee excellent efficiency, two TLINs are used in the second stage to control the harmonics. At 0 dBm, the power conversion efficiency (PCE) is 51.2% and 56.7% at 2.4 and 5.8 GHz, respectively, at a load of 1.2 kΩ. At 2.4 GHz, PCE reaches a peak of 68% at 13 dBm. At 5.8 GHz, PCE enhances up to 89% at 17 dBm. At 2.4 and 5.8 GHz, the PCE exceeds 70% of the peak over a wide input power range of −3 to 18 and 1.5–18 dBm, respectively. For verification, the proposed rectifier is fabricated. The simulation results are consistent with the measurements. The proposed rectifier performs well in terms of compactness and rectification effectiveness. It provides a solution for powering low‐power devices. [ABSTRACT FROM AUTHOR]

This work presents the two port ultra-wide band MIMO antenna with novel isolation structure and dual band RF Rectifier for 3.3 GHz and 4.65 GHz frequencies for RF energy harvesting applications. The anticipated antenna is systematically examined within the ultra-wideband (UWB) range from 3.1 GHz to 10.6 GHz design frequency with four different steps: Antenna 1, Antenna 2, Antenna 3 and Antenna 4 (optimal design) are chosen for comprehensive study. A unique isolation structure was developed between two identical elements separated by 10 mm, resulting in an enhanced isolation of −23.5 dB at 3.15 GHz, −27 dB at 5.8 GHz, −28 dB at 9.26 GHz and greater than −34 dB at 7.5 GHz. The suggested antenna resonates at UWB band and have fractional bandwidth of 118.66 % and a peak gain of 4.1 dB at 3.15 GHz, 3.68 dB at 5.8 GHz, 6.4 dB at 7.5 GHz and 3.2 dB at 9.26 GHz has been obtained. Radiation efficiencies of 92.5 %, 95 %, 90 % and 84.5 % at 3.15 GHz, 5.8 GHz, 7.5 GHz and 9.26 GHz were obtained respectively. The recommended MIMO performance is simulated using HFSS in terms of ECC, DG, MEG and CCL. The results adhere to specified requirements and confirmed by experimentation. An HFSS simulated dataset of reflection coefficient is used as input for the various ML algorithms namely, Support Vector Machine (SVM), Ensemble, k-nearest neighbors' algorithm (KNN) and Gaussian Process Regression (GPR) models are trained with 80 % of the data and testing with 20 % of the data. The test results are compared and corresponding performance values of MAE, RMSE, MSE & R2 are 0.00029, 0.00197, 3.87e−6 and 1.0 validation results and corresponding test results are 0.00031, 0.00229, 5.20e−6 and 0.999. Finally, the proposed dual band rectifier with a shorted stub is tested for harvesting applications at 3.3 GHz and 4.65 GHz frequency and it attained RF to DC conversion efficiencies of 69 % and 55.40 % respectively. [ABSTRACT FROM AUTHOR]

Rectifier plays a pivotal role in wireless power transfer systems. While numerous studies have concentrated on enhancing efficiency and bandwidth at specific high-power levels, practical scenarios often involve unpredictable power inputs. Consequently, a distinct need arises for a rectifier that demonstrates superior efficiency across a broad range of input power levels. This paper introduces a high-power RF-to-DC rectifier designed for WPT applications, featuring an ultrawide dynamic range of input power. The rectification process leverages a GaN (gallium nitride) high electron mobility transistor (HEMT) to efficiently handle high power levels up to 12.6 W. The matching circuit was designed to ensure that the rectifier will operate in class-F mode. A Schottky diode is incorporated into the design for relatively lower-power rectification. Seamless switching between the rectification modes of the two circuits is accomplished through the integration of a circulator. The proposed rectifier exhibits a 27.5 dB dynamic range, achieving an efficiency exceeding 55% at 2.4 GHz. Substantial improvement in power handling and dynamic range over traditional rectifiers is demonstrated. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive review of the design and implementation methods of low-power piezoelectric energy harvesting circuits, which in the last few years have gained an extremely large range of applications like the power sources of wearable electronic devices, such as biometrical sensors. Before examining the electronic circuitries of the self-supplied power devices, an overview of the structure, equivalent electrical circuits, and basic parameters of the piezoelectric generators and MEMSs as energy harvesting elements is presented. The structure of energy storage elements (parallel-plate capacitors and thin-film supercapacitors), suitable for this type of application, is also presented. The description of these components from an electrical point of view allows them to be easily workable when connected to the various power conversion electronic circuits. Based on an overview of the structure and the principles of operation, as well as some analytical expressions for energy efficiency evaluation, a comprehensive comparative analysis is presented. Depending on the advantages and disadvantages of the known circuit configurations, the basic electrical and design parameters are systematized in tabular form. Practical realizations of piezoelectric power conversion circuits are also presented in graphic form, ensuring the optimal value of energy efficiency and compactness in the construction of the devices. [ABSTRACT FROM AUTHOR]

This article introduces an isolated three-phase six-pulse rectifier using a solid-state transformer. The line frequency utility grid voltage is modulated by a frequency boost converter. This converter exists two parts. The first part is the rectifier section, and the second one is the inverter section. Then after, three-phase diode rectifier is powered by the medium frequency transformer 2 kHz to shrink the transformer size upto 20% or even 10% depensing to the frequency operating range for silicon steel core materials. The aim of this study is to shrink the occupied size of the rectifier using a higher frequency transformer. The study realizes that the grid line current has the same frequency contents as a regular three phase rectifier. In other words, the presented idea results in smaller weight and size while sustaining the performance of input current total harmonic distortion THD=31%. High power density power electronics converter would be extremely valuable for applications such as electric vehicle railways and aircraft. The proposed approach is reliable and easy to use. The solid-state transformer contributes to isolating and improving the overall converter's power density. Simulation results for the 16 kW converter were verified using MATLAB Simulink. [ABSTRACT FROM AUTHOR]

A new type of single–conversion–step wide–input–range versatile step–up/down three–voltage–level power–factor correction stage is presented in this manuscript. The rectifier can operate both in continuous–conduction mode and discontinuous–conduction mode. First, the rectifier's principle of operation is described, and then the innovative rectifier is analyzed in continuous and discontinuous–conduction modes. After, an average model for the innovative rectifier is developed. Lastly, the proposed theory is experimentally validated using a multiplier–less dual–control–loop mode at discontinuous–conduction modes. It is shown that although no multiplier is used in the control circuitry, the power factor is near unity. It is revealed that the rectifier can swing the output voltage from 50 V to 900 V while the input voltage is 230 Vrms. Although the rectifier output has a split DC bus with three voltage levels, the required control effort is low, and the output voltage is balanced. The innovative topology suits any standard power–factor correction rectifier application, dual–stage low–voltage power supply, and three–level voltage supplement for low–harmonic inverters. Since the rectifier's output–voltage swing is extremely wide, energy storage systems and electric vehicle batteries are suitable applications. [ABSTRACT FROM AUTHOR]

This paper presents a novel adaptive reconfigurable rectifier architecture for radio frequency energy harvesting (RFEH); in addition, a new metric for high-efficiency dynamic range (DR) is proposed. The presented rectifier architecture is based on a double-sided diode-feedback cross-coupled differential-drive rectifier (CCDR) structure incorporating self-body bias for reconfigurable operation. An adaptive structure based on a Schmitt trigger is proposed to adaptively switch the rectifier connection without auxiliary voltage (Vaux), with two rectifier stages in parallel at low power and in series at high power. The system is simulated at a 180 nm CMOS process and the results show more than 17 dB DR at 900 MHz, with efficiency higher than 50% at a 100 kΩ load. [ABSTRACT FROM AUTHOR]

Copyright of Electric Drive is the property of Electric Drive Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A wide-speed, ultra-light power generation system is a critical power generation unit structure, often because of its high efficiency and power density. Lightness and reliability are two key design indicators within the system, albeit they could lead to contradictory problems, particularly in systems containing prime movers, batteries, generators, rectifiers, and inverters. Ultra-light generator sets are facing more severe problems and contradictions in designing in terms of matching, coordinating, and stabilizing the components in the systems. This paper describes the system design of a low-cost and high-reliability microgenerator set: a gasoline engine, three-phase permanent magnet synchronous generator, rectifier, and inverter. Moreover, the matching relationship between the four parts and the design effect of each part of the power generation system was analyzed, simulated, and tested to verify the effectiveness and feasibility of the so-designed system. [ABSTRACT FROM AUTHOR]

In this study, a high-efficiency, high-power synchronous rectifier based on transistors was designed. The widely used diode-based rectifiers have a relatively simple structure but are unsuitable for high-power applications, such as unmanned aerial vehicle and electric vehicle charging. In contrast, transistor-based rectifiers operate by reversing the power flow of a switch-mode power amplifier from the load to the DC supply based on time-reversal duality and can rectify efficiently, even at a high power of 30 dBm or more. The proposed transistor-based synchronous rectifier was designed to have a high rectification efficiency by controlling the harmonics to operate in the inverse Class-F mode and achieved a peak efficiency of 73.2% at an input power of 37 dBm. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Nanjing University of Information Science & Technology (Natural Science Edition) / Nanjing Xinxi Gongcheng Daxue Xuebao (ziran kexue ban) is the property of Editorial Office of Journal of Nanjing University of Information Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Heterostructures of two‐dimensional materials realise novel and enhanced physical phenomena, making them attractive research targets. Compared to inorganic materials, coordination nanosheets have virtually infinite combinations, leading to tunability of physical properties and are promising candidates for heterostructure fabrication. Although stacking of coordination materials into vertical heterostructures is widely reported, reports of lateral coordination material heterostructures are few. Here we show the successful fabrication of a seamless lateral heterojunction showing diode behaviour, by sequential and spatially limited immersion of a new metalladithiolene coordination nanosheet, Zn3BHT, into aqueous Cu(II) and Fe(II) solutions. Upon immersion, the Zn centres in insulating Zn3BHT are replaced by Cu or Fe ions, resulting in conductivity. The transmetallation is spatially confined, occurring only within the immersed area. We anticipate that our results will be a starting point towards exploring transmetallation of various two‐dimensional materials to produce lateral heterojunctions, by providing a new and facile synthetic route. [ABSTRACT FROM AUTHOR]

Heterostructures of two‐dimensional materials realise novel and enhanced physical phenomena, making them attractive research targets. Compared to inorganic materials, coordination nanosheets have virtually infinite combinations, leading to tunability of physical properties and are promising candidates for heterostructure fabrication. Although stacking of coordination materials into vertical heterostructures is widely reported, reports of lateral coordination material heterostructures are few. Here we show the successful fabrication of a seamless lateral heterojunction showing diode behaviour, by sequential and spatially limited immersion of a new metalladithiolene coordination nanosheet, Zn3BHT, into aqueous Cu(II) and Fe(II) solutions. Upon immersion, the Zn centres in insulating Zn3BHT are replaced by Cu or Fe ions, resulting in conductivity. The transmetallation is spatially confined, occurring only within the immersed area. We anticipate that our results will be a starting point towards exploring transmetallation of various two‐dimensional materials to produce lateral heterojunctions, by providing a new and facile synthetic route. [ABSTRACT FROM AUTHOR]

In this paper, photonic generation of arbitrary shape radio-frequency (RF) waveforms like triangular, square and fullwave rectifier types are demonstrated based on a dual-parallel Mach–Zehnder modulator (DP-MZM) driven by a single sinusoidal RF signal. In the proposed technique, one of the sub-MZM (MZM-2) has no driven signal, while other the sub-MZMs (MZM-1) of the DP-MZM is driven by the sinusoidal RF signal. The powers of even and odd-order sidebands are separately controlled by proper adjustment of modulation index through modulating the bias of the MZM-1. An RF signal with controllable harmonics are generated, after detecting the modulated signal by a photodetector. Thus, by separately modulating its harmonics a desired RF waveform is generated. The proposed method is theoretically analysed followed by experimental validation. [ABSTRACT FROM AUTHOR]

The paper introduces a new circuit structure of precision full-wave rectifier, without the requirement of any diode(s) and passive component(s), which operates in current mode. The proposed structure of the rectifier employs a single current follower differential input transconductance amplifier and two MOS transistors only. The use of the least number of active components makes the circuit structure simple and favorable to the contemporary integration technology. The proposed rectifier has wider input current dynamic range (±1.6 mA), lower current offset (84 pA), and can operate up to 30 MHz frequency. Additionally, the circuit is easily cascadable, temperature insensitive, and less affected by process variation, MOS transistors mismatch, and supply voltage variation. The rectifier circuit is verified through 0.18 µm gpdk technology-based post-layout simulation results using the cadence Virtuoso tool. The rectification accuracy is examined through the parameters, such as average value ratio and root mean square error. The proposed rectifier's layout measures 31.95 µm × 31.35 µm in size. [ABSTRACT FROM AUTHOR]

This paper proposes the design of a compact and highly efficient 2.45 GHz rectifier based on harmonic suppression. The proposed rectifier enhanced the RF–DC efficiency by suppressing the second and third harmonics. Additionally, a second harmonic suppression network was used for matching, thereby eliminating the need for an additional input impedance matching network and resulting in a smaller size. The fabricated rectifier demonstrated a very high power conversion efficiency (PCE) of 81.22 % at an input power of 12.5 dBm, with dimensions of 19 mm×15.5 mm. [ABSTRACT FROM AUTHOR]

This paper proposes a self-supplied power management system to efficiently rectify and regulate the AC voltage received from wireless power transmission techniques to power or recharge biomedical devices. The proposed power management system comprises three integrated functional units, namely, a fully cross-coupled rectifier, a self-biased reference voltage, and a capacitor-less low-dropout regulator (LDO). To reduce the current complexity of designing capacitor-less LDOs, a new architecture based on a pair of diode-connected transistors at the load of the LDO is devised which alleviates the need for a large load capacitor. The proposed power management system is implemented in a 65-nm CMOS process with an active chip area of 0.0810 mm2. Experimental results indicate that this system is capable of rectifying an AC signal up to 5 V at a frequency of 6.78 MHz. This rectified signal is then regulated to a fixed DC voltage of 1.75 V, while the load current can vary between 0 and 75 mA, with a maximum voltage dropout of 170 mV. Advantageously, the proposed power management system is significantly robust to temperature, as a 55 °C change in ambient temperature leads to only a 9% degradation in its overall performance. Furthermore, the ability of the power management system to drive low-power consumer electronics is demonstrated, and its superiority is evidenced by a performance comparison with the latest integrated power management systems presented in the literature. [ABSTRACT FROM AUTHOR]

Traditional current and voltage strategies proposed for the single-phase rectifier with pulse width modulation (PWM) used in the AC charging system for electric vehicles, have a large response time and the percentage of total harmonic distortion (THD) of the line current is more than 2%, which causes a reduction of the power factor (PF). The present paper focuses on the robust sliding mode current–voltage control (SMCVC) design for the single-phase rectifier with PWM. This SMCVC strategy used the grid current directly without any rotating coordinate transformations and reduced the complexity computational of the implementation algorithm and allows to satisfy the following desired performances, low THD of the input current and the PF is around one in a faster response time. In this paper, the proposed control strategy is compared and verified with proportional integral (PI) control and proportional integral sliding mode current control (PI-SMCC) by Matlab/Simulink. At the end of this paper, simulation examples are given to illustrate our approach and to show that our proposed method provides very good results with respect to some literature results. [ABSTRACT FROM AUTHOR]

This paper presents the design and fabrication of a rectenna that receives 2.45 GHz RF signals and converts them into DC power. The rectenna comprises a patch antenna, matching network, and rectifier. It was manufactured and measured using a 0.76-mm thick RF-35A2 board. The matching network was implemented using transmission lines and open stubs and designed to stably convert the RF signal into a fixed DC voltage by employing parallel inductors. The measured rectenna achieved a maximum RF–DC conversion efficiency of 38 % at 2.3-dBm input power and a 1.5-kΩ load. When used in conjunction with the fabricated patch antenna, it transmitted 1.8 V of power at 36 mW into a 90-Ω load at a distance of 10 cm. [ABSTRACT FROM AUTHOR]

A hypoglossal nerve stimulator (HGNS) is an invasive device that is used to treat obstructive sleep apnea (OSA) through electrical stimulation. The conventional implantable HGNS device consists of a stimuli generator, a breathing sensor, and electrodes connected to the hypoglossal nerve via leads. However, this implant is bulky and causes significant trauma. In this paper, we propose a minimally invasive HGNS based on an electrocardiogram (ECG) sensor and wireless power transfer (WPT), consisting of a wearable breathing monitor and an implantable stimulator. The breathing external monitor utilizes an ECG sensor to identify abnormal breathing patterns associated with OSA with 88.68% accuracy, achieved through the utilization of a convolutional neural network (CNN) algorithm. With a skin thickness of 5 mm and a receiving coil diameter of 9 mm, the power conversion efficiency was measured as 31.8%. The implantable device, on the other hand, is composed of a front-end CMOS power management module (PMM), a binary-phase-shift-keying (BPSK)-based data demodulator, and a bipolar biphasic current stimuli generator. The PMM, with a silicon area of 0.06 mm 2 (excluding PADs), demonstrated a power conversion efficiency of 77.5% when operating at a receiving frequency of 2 MHz. Furthermore, it offers three-voltage options (1.2 V, 1.8 V, and 3.1 V). Within the data receiver component, a low-power BPSK demodulator was ingeniously incorporated, consuming only 42 μ W when supplied with a voltage of 0.7 V. The performance was achieved through the implementation of the self-biased phase-locked-loop (PLL) technique. The stimuli generator delivers biphasic constant currents, providing a 5 bit programmable range spanning from 0 to 2.4 mA. The functionality of the proposed ECG- and WPT-based HGNS was validated, representing a highly promising solution for the effective management of OSA, all while minimizing the trauma and space requirements. [ABSTRACT FROM AUTHOR]

Copyright of Dyna is the property of Universidad Nacional de Colombia, Medellin, Facultad de Minas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents the deployment of a hybrid energy harvesting system that combines a wireless energy harvesting (EH) system and a 6 V, 170 mA monocrystalline solar energy derived from the Sun's rays. The hybrid energy harvesting (HEH) system comprises the rectifier, the solar cell panel, the charging circuit, and the EM4325 embedded RFID tag. This study aims to design an efficient EH system capable of increasing the read range of an active RFID tag. The proposed approach integrates a meandered line radio frequency identification (RFID) tag with an EM4325 IC chip as the receiver antenna. A halfwave doubler RF rectifier circuit is connected to the antenna using a 50 Ω SMA connector to convert the captured RF waves into usable electrical power. A solar energy charging module equipped with a Maximum Power Point Tracking (MPPT) system, a rechargeable lithium-ion battery, and a DC-DC converter is configured to manage and store the harvested energy efficiently. The UHF tag antenna operates at 919 MHz, achieving a peak gain of 3.54 dB. The proposed rectenna achieves a maximum measured harvested power conversion efficiency (PCE) of 55.14% for an input power (Pin) of 15 dBm at a distance of 5.10 cm, while the solar cell panel realizes 3.92 W of power. Experimental results demonstrate the hybrid harvester system's effectiveness, achieving a PCE of 86.49% at an output voltage (VDC) of 5.35 V. The main advantage of this approach is the creation of a compact hybrid RF and solar EH system by combining the solar cell panel with the antenna, thus enabling multi-functionality. [ABSTRACT FROM AUTHOR]

There is a global trend to reduce emissions from cars through the adoption of other alternatives, such as electric vehicles (EVs). The increasing popularity of EVs has led to a growing demand for electric vehicle chargers. EV chargers are essential for charging the batteries of EVs. Since the EV charger stays connected to the grid for long periods of time to charge the EV battery, it must be able to handle disturbances in the power grid. The goal of this paper is to present an overview of the impact of grid events on EV battery chargers. As well as the impact of grid unbalances on EV chargers, this paper also provides an overview of the impact of grid faults on other, similar power electronics interfaced resources such as PV and energy storage systems. [ABSTRACT FROM AUTHOR]

This paper presents the design of highly efficient rectifiers that can operate at WiFi frequencies (2.45 GHz and 5.8 GHz) and match low input power. The designed dual-band rectifiers use multi-stage dickson voltage multipliers (DVM) (from 1 to 6 stages), and the main idea of this paper is to find the number of stages that offers the best performance and that can be used by applications that operate within the same constraints (operating frequencies, input power). The efficiency and the output voltage (Vout) are the parameters studied to analyze the designed rectifiers. The results showed that as the number of DVM stages increased, the efficiency curves for both frequencies shifted to the higher input power range, even when using the same diode (SMS7630) and the same load (5 KO). We concluded that the rectifier with 1-stage DVM is the most suitable to be used for low input power at the selected frequencies since it provides an efficiency of 57.734% at 0 dBm for 2.45 GHz and 36.225% at 1 dBm of input power for 5.8 GHz. [ABSTRACT FROM AUTHOR]

A comprehensive model for micro-powered piezoelectric generator (PG), analysis of operation, and control of voltage doubler joule thief (VDJT) circuit to find the piezoelectric devices (PD's) optimum functioning points are discussed in the present article. The proposed model demonstrates the power dependence of the PG on mechanical excitation, frequency, and acceleration, as well as outlines the load behaviour for optimal operation. The proposed VDJT circuit integrates the combination of voltage doubler (VD) and joule thief circuit, whereas the VD circuit works in Stage 1 for AC (alternating current)–DC (direct current) conversion, while a joule thief circuit works in Stage 2 for DC–DC conversion. The proposed circuit functions as an efficient power converter, which converts power from AC–DC and boosts the voltage from low to high without employing any additional electronic components and generating duty cycles. The electrical nature of the input (i.e., PD) of a VDJT circuit is in perfect arrangement with the investigated optimisation needs when using the proposed control circuit. The effectiveness of the proposed VDJT circuit is examined in terms of both simulation and experiment, and the results are presented. The proposed circuit's performance was validated with available results of power electronics interfaces in the literature. The proposed circuit's flexibility and controllability can be used for various applications, including mobile battery charging and power harvesting. [ABSTRACT FROM AUTHOR]

This work presents the experimental validation of a 40 kW electric vehicle (EV) charger. The proposed system comprises two 20 kW modules connected in parallel at the input and output. Each module has two stages—as a grid converter Vienna Rectifier (VR) was chosen, and as an isolated DC/DC stage, two Series-Resonant Dual-Active-Bridges (SRDABs) in input-series-output-parallel (ISOP) configurations were applied. The AC/DC and DC/DC stages were enclosed in 2U rack standard housing. A bipolar DC-link with ±400 V DC voltage was employed to connect both stages of the charger module while the charger's output is dedicated to serving 800 V batteries. VRs operated at 66 kHz switching frequency and the SRDABs operated at 100 kHz. The converters used in the charger structure were based on silicon carbide (SiC) power devices. The description and parameters of the built hardware prototypes of both—AC/DC and DC/DC—converters are provided. Moreover, the experimental validation of each stage and the whole charging system, including oscilloscope waveforms and power analyzer measurements at nominal power, are included. Such a configuration enables energy conversion with high efficiency without a negative impact on the grid and high-quality grid waveforms. [ABSTRACT FROM AUTHOR]

This paper presents the experimental design and characterization of an optimized radio-frequency energy-harvesting prototype device to operate in the GSM 900 band. The energy harvesting device is based on an off-the-shelf GSM antenna, Schottky diode rectifier, and was implemented on a standard FR4 substrate. The experimental results show that the harvesting device is capable of generating 0.3 V DC voltage at an input power of −17 dBm at 956 MHz frequency. The measured efficiency of the developed energy harvesting system was 68%, at RL = 1.6 kΩ, which is a very significant performance relative to other prototypes of the same class reported in literature. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Engineering Research & Development (IJERAD) is the property of International Journal of Engineering Research & Development and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper explains step-by-step modeling and simulation of the full circuits of a battery control system and connected together starting from the AC input source to the battery control and storage system. The three-phase half-controlled rectifier has been designed to control and convert the AC power into DC power. In addition, two types of direct current converters have been used in this paper which are a buck and bidirectional DC/DC converters. These systems adjust the output voltage to be lower or higher than the input voltage. In the buck converters, the main switch operates in conduction or cut-off mode and is triggered by a Pulse-Width Modulated (PWM)signal. The output and input voltage levels ratio are used to calculate thePWMsignal's duty cycle. Therefore, the duty cycle indicates the operation mode of the converter in steady-state operation. In this study, we analyze and control of a buck converter with the PWM signal. Besides, the bidirectional DC/DC converter has been achieved and optimized by PI control methods to control the battery charging and discharging modes. The simulation has been applied via the Matlab/Simulink environment. The results show the activity of each part of the designed circuits starting from the converters and the battery control system in charge and discharge modes. [ABSTRACT FROM AUTHOR]

Single-loop current sensorless control allows for abolishing of the instantaneous current measurement in the control system using only a single control loop with voltage feedback to stabilise the DC-bus voltage. This approach eliminates current sensors in the control circuit, benefiting from saving space on the printed circuit board and minimising power dissipation in the current measurement circuitry. This paper focuses on the single-loop current sensorless control applied to bidirectional three-phase four-wire three-level NPC MLC by simulation analysis and demonstrates the performance of the proposed current control algorithm in the rectifier and inverter modes and the step response with power direction change and grid-voltage change. In capacitor voltage balancing, an additional controller is applied, which is capable of compensating for the voltage asymmetry caused by adding a 2.5 kOhm resistor in parallel to one of the DC-bus capacitors. Our results demonstrate good performance of the proposed control method both in the inverter and rectifier modes, showing stable current shape in the low power and full power modes with acceptable harmonics content, meeting the requirements of the IEC 61000-3-2 standard for Class A devices. The analysis showed that the proposed control approach is suitable for industrial application. [ABSTRACT FROM AUTHOR]

Optimized vertical heterojunction rectifiers with a diameter of 100 µm, consisting of sputter-deposited p-type NiO forming a p–n junction with thick (10 µm) Ga2O3 drift layers grown by halide vapor phase epitaxy (HVPE) on (001) Sn-doped (1019 cm−3) β-Ga2O3 substrates, exhibited breakdown voltages > 8 kV over large areas (>1 cm2). The key requirements were low drift layer doping concentrations (<1016 cm3), low power during the NiO deposition to avoid interfacial damage at the heterointerface and formation of a guard ring using extension of the NiO beyond the cathode metal contact. Breakdown still occurred at the contact periphery, suggesting that further optimization of the edge termination could produce even larger breakdown voltages. On-state resistances without substrate thinning were <10 mΩ·cm−2, leading to power figure-of-merits > 9 GW·cm−2. The devices showed an almost temperature-independent breakdown to 600 K. These results show the remarkable potential of NiO/Ga2O3 rectifiers for performance beyond the limits of both SiC and GaN. The important points to achieve the excellent performance were: (1) low drift doping concentration, (2) low power during the NiO deposition and (3) formation of a guard ring. [ABSTRACT FROM AUTHOR]

This paper presents a new rectifier design for radio frequency (RF) energy harvesting by adopting a particular circuit topology to achieve two objectives at the same time. First, work with modulated input signal sources instead of only continuous waveform (CW) signals. Second, operate with a wide input power range using the Wilkinson power divider (WPD) and two different rectifier diodes (HSMS2852 and SMS7630) instead of using active components. According to the comparison with dual-band rectifiers presented in the literature, the designed rectifier is a high-efficiency rectifier for wide RF power input ranges. A peak of 67.041% and 49.089% was reached for 2.45 and 5.8 GHz, respectively, for CW as the input signal. An efficiency of 72.325% and 45.935% is obtained with a 16 QAM modulated input signal for the operating frequencies, respectively, 69.979% and 54.579% for 8PSK. The results obtained demonstrate that energy recovery systems can use modulated signals. Therefore, the use of a modulated signal over a CW signal may have additional benefits. [ABSTRACT FROM AUTHOR]

In this study, the design and measurement results of a 5.8 GHz GaN HEMT Class-F rectifier using a voltage doubler were proposed. The proposed rectifier employed a voltage doubler for high-output dc voltage characteristics and applied the technique of opening the third-harmonic impedance to an input-matching network to obtain high-efficiency characteristics. A GaN HEMT bare chip with a high breakdown voltage and wide bandgap was used as a diode, which enabled stable operation at a high input power. Four methods of electrically connecting a bare chip to a PCB were proposed, and fabrication and measurements were conducted to verify the optimal electrical connection method. At 5.8 GHz, with an input RF power of 32 dBm and load resistance of 1,000 Ω, the fabricated rectifier exhibited RF-dc conversion efficiency of over 55 % in all methods. Maximum efficiency of 69 % was obtained in a circuit in which the cathodes of series and parallel diodes were connected to the PCB with bond-wires, and the anode of the parallel diode was connected to the PCB with through-wafer via. [ABSTRACT FROM AUTHOR]

With low-power gadgets proliferating, the development of a small, effective rectenna is crucial for wirelessly energizing devices. A simple circular patch with a partial ground plane for RF-energy harvesting at ISM (2.45 GHz) band is proposed in this work. The simulated antenna resonates at 2.45 GHz with an input impedance of 50 Ω and a gain of 2.38 dBi. An L-section matching a circuit with a voltage doubler is proposed to provide excellent RF-to-DC transformation efficiency at low power input. The proposed rectenna is fabricated and the results show that the return loss and realized gain have good characteristics at the ISM band with 52% of RF-to-DC transformation efficiency, with an input of 0 dBm power. The projected rectenna is apt for power-up low sensor nodes in wireless sensor applications. [ABSTRACT FROM AUTHOR]

The demand for increased voltage in renewable energy sources is relatively high. This study examines the rapid development of technology considering the use of voltage-increasing transformers. Voltage regulator circuits are generally used to stabilize the output voltage of the rectifier according to the amount of input from the transformer. However, components for highvoltage stabilizer circuits are rare, which becomes an obstacle to the stabilization of the rectifier output. This study aimed to determine the performance of the designed rectifier circuit against a non-center tap step-up direct current (DC) 400 V transformer and compare the measurement results to manual calculations. The research method is a direct comparison between the input and output voltage values of the transformer after going through a rectifier circuit. This experiment was conducted using the repeatability method three to five times for each voltage variation on the transformer. The voltage variations successfully created are 0 to 50, 0 to 100, 0 to 200, and 0 to 400 V. The output test results from the DC transformer and rectifier circuit show linear results and an increase in peak-to-peak voltage data between the transformer and rectifier outputs by 3.8%. [ABSTRACT FROM AUTHOR]

This paper presents the converter design of a single-phase non-isolated step-down controlled rectifier for power factor improvement and output voltage regulation. The converter consists of a full-bridge diode rectifier and a DC–DC interleaved buck converter of two or more switching cells that has an LC filter in its input. It is proposed that the interleaved switching cells operate in discontinuous conduction mode and the current through the input LC filter be continuous, avoiding switching frequency components to be injected into the grid. The controller, which has a simple structure and a small number of sensors, allows the system to achieve a high power factor. It also regulates the output voltage to a constant reference. An experimental prototype is built and tested to validate the analysis and proposed design. The closed-loop converter is evaluated both in a steady state and in transient conditions. At steady state, the converter achieves a power factor above 0.9 with a maximum of 45.4% THD at 110.1W. The main contributions of this paper are guidelines for the design of the converter, open-loop analysis, and converter control. [ABSTRACT FROM AUTHOR]

Miniaturised piezoelectric devices are emerging energy harvesting sources that are appropriate for various implantable and wearable applications. However, these piezoelectric devices exhibit considerable internal resistance due to their internal impedance, which leads to self-start and low-energy conversion failures. This paper describes a dual-stage boost converter circuit by facilitating self-powering features and boosting the low voltage harvested by the piezoelectric devices into dc. The proposed circuit comprises conversion stages of ac-dc and dc-dc in Stages I and II, respectively. In addition, the proposed circuit does not require employing the auxiliary circuits to generate the train pulses by triggering the bidirectional switches to envelop the current being stored in Stage II and kick-start the self-powered circuit for piezoelectric energy harvesting systems. Theoretical assumptions and control strategies were tested and verified with ideal and impedance input sources. The proposed circuit could convert a low voltage of 3 Vac into 19 Vdc. The maximum attained output power by the proposed circuit was 3.61 mW. The outcome depicted that the proposed circuit boosted the low voltage and outperformed the existing literature circuits in terms of output voltage and power. [ABSTRACT FROM AUTHOR]

Active Front-End (AFE) rectifiers have regained momentum as the demand for highpower Electric Vehicle (EV) charging infrastructure increases exponentially. AFE rectifiers have high efficiency and reliability, and they minimize the disturbances that could be generated due to the operation of the EV charging systems by reducing harmonic distortion and operating close to the Unity Power Factor (UPF). The purpose of this review is to present the current state-of-the-art AFE rectifiers used in fast chargers, focusing on the comparison between different AFE topologies and their components, as well as modular AFE solutions. Furthermore, different control strategies of AFE converters are presented and compared. Some of their more widely used control techniques, namely Voltage Oriented Control (VOC), Direct Power Control (DPC), Hysteresis Current Control (HCC), and Model Predictive Control (MPC), have been implemented, and their performance compared. Centralized and distributed control systems are compared for operating parallel AFE rectifiers for modular, fast charging systems. An overview of cooling systems and reliability evaluation tools is also presented. Finally, trends and future outlooks are analyzed. [ABSTRACT FROM AUTHOR]

This paper describes the detailed modelling of a vibration-based miniature piezoelectric device (PD) and the analysis modes of operation and control of a voltage doubler boost converter (VDBC) circuit to find the PD's optimal operating conditions. The proposed VDBC circuit integrates a conventional voltage doubler (VD) circuit with a step-up DC-DC converter circuit in modes 1–4, while a non-linear synchronisation procedure of a conventional boost converter circuit is employed in modes 5–6. This integration acted as the voltage boost circuit without utilising duty cycles and complex auxiliary switching components. In addition, the circuit does not require external trigger signals to turn on the bidirectional switches. This facilitates the operation of VDBC circuit at very low AC voltage (Vac ≥ 0.5 V). Besides this, the electrical characteristics of VDBC circuit's input (i.e., PD) perfectly concurs with the studied testing scenarios using impedance power sources (mechanical shaker). Firstly, the proposed circuit which can rectify the PD's output was tested at both constant input voltage with varying excitation frequency and constant excitation frequency with varying input voltage. Next, a small-scale solar battery was charged to validate the feasibility of the performance of the proposed VDBC circuit. The proposed circuit achieved a maximum output voltage of 11.7 Vdc with an output power of 1.37 mW. In addition, the rectified voltage waveform is stable due to the sminimisation of the ripples. In addition, the performance of VDBC circuit was verified by comparing the achieved results with previously published circuits in the literature. The results show that the proposed VDBC circuit outperformed existing units as described in the literature regarding output voltage and power. The developed rectifier circuit is suitable for various real-life applications such as energy harvesting and battery charging. [ABSTRACT FROM AUTHOR]

Converters are one of the most sensible components of any power conversion system when it comes to electrical faults. Moreover, if these converters are used in a rotating system, as is the case with rotating rectifiers used in brushless synchronous machines, apart from also being exposed to mechanical effects and thus having a greater likelihood of failure, no access is available directly, causing a lack of available measurements for condition monitoring. This paper applies a model-based method to the online detection of open-diode faults, shorted-diode faults and exciter open-phase faults in the rotating rectifiers of brushless synchronous machines. The applied method relies on the comparison between the measured and the theoretical exciter field currents, the latter computed through a healthy machine model from the machine actual output values. The proposed protection strategy stands out for its computational simplicity and its non-invasiveness, which makes its industrial application straightforward without the need of any further equipment or adaptation. Its applicability has been verified through a double approach, on the one hand, through computer simulations, and, on the other hand, through experimental tests, achieving satisfactory results. The research conducted proves that with the proposed method, given reasonable measurement and model estimation typical errors of less than 5%, positive differences between the measured and the theoretical exciter field currents of more than 13%, 200% and 30% for open-diode faults, shorted-diode faults and exciter open-phase faults, respectively, are detectable with at least a 95% confidence interval. [ABSTRACT FROM AUTHOR]

This article proposes a high-efficiency single-phase GaN-based rectifier with reactive power transfer for use in front-end power supplies as an efficient alternative to centralized reactive power compensation. A full-range zero-voltage switching (ZVS) modulation for both unity power factor (PF) operation and nonunity PF operation is proposed for the GaN-based rectifier in critical conduction mode (CRM) operation. A frequency limitation method is also developed to limit the peak frequency during the ac current zero-crossing. Also, a GaN-based T-type totem-pole rectifier is proposed to overcome the control challenge in CRM during the ac voltage zero-crossing. Meanwhile, a digital-based control scheme is developed to implement ZVS operation and reactive power regulation. The proposed rectifier and ZVS control have the advantages of simple topology, high efficiency, straightforward control implementation, and capability of flexible reactive power regulation. A 1.6-kVA prototype of the GaN-based CRM T-type totem-pole rectifier is built and demonstrated with full-range ZVS operation, 98.9% full-load efficiency, and flexible reactive power regulation with smooth dynamic response. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shanghai University / Shanghai Daxue Xuebao is the property of Journal of Shanghai University (Natural Sciences) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For longer journeys, when drivers of electric vehicles need a charge on the road, the best solution is off-board ultra-fast chargers, which offer a short charging time for electric vehicle batteries. Consequently, the ultra-fast charging of batteries is a major issue in electric mobility development globally. Current research in the area of power electronics for electric vehicle charging applications is focused on new high-power chargers. These chargers will significantly increase the charging power of electric vehicles, which will reduce the charging time. Furthermore, electric vehicles can be deployed to achieve improved efficiency and high-quality power if vehicle to microgrid (V2µG) is applied. In this paper, standards for ultra-fast charging stations and types of fast charging methods are reviewed. Various power electronic topologies, the modular design approach used in ultra-fast charging, and integration of the latter into standalone microgrids are also discussed in this paper. Finally, advanced control techniques for ultra-fast chargers are addressed. [ABSTRACT FROM AUTHOR]

This work demonstrates the design of a single band Electromagnetic Band Gap (EBG) antenna by employing an open stub EBG microstrip of a patch antenna for better achievements in terms of its performance to be utilized in a reconfigurable harvester to operate over a wide input power range. The EBG antenna has been used to gather RF energy and a FET-transistor has been obtainable to determine and control the power flow with the intention to operate at the same time for a different level of input power. The measured data of the EBG antenna shows a directivity of 8.52 dBi, a gain of 7.18 dBi, a return loss of -27 dB with a radiation efficiency of 84.3%, showing a clear enhancement in directivity, peak realized gain, and radiation efficiency by 41.76%, 25.61%, and 17.12% respectively compared with a regular reference antenna; without utilized the EBG structure. Moreover, the harvester design accomplishes 40% of RF-DC power conversion efficiency over a wide dynamic input power range from -15 to 27 dBm, and its peak is around 78%. The harvester is designed to work at the ISM band for 915 MHz and is suitable for Wireless Power Transfer (WPT) uses. [ABSTRACT FROM AUTHOR]

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)