Recovery Loss Research Articles

Research on gas–liquid separation characteristics in the helico-axial multiphase pump

Due to the fact that it serves as both a pump and a compressor, the helico-axial multiphase pump is better suited for mixed-transport oil-gas two-phase flow and is frequently used for deep-sea oil extraction. The gas–liquid separation caused by the asynchrony of the gas–liquid two-phase medium is the primary cause of the damage or failure of the helico-axial multiphase pump in the project, resulting in the pump's damage or inability to operate. To investigate the variation of phase separation in the helico-axial multiphase pump under diverse operating conditions, a test system was designed and the theory of fluid flow mechanics was applied. The effects of different flow fields on the energy conversion characteristics of the pump were investigated. The results indicate that the gas–liquid separation position in the impeller occurs near the 2/3 of the airfoil bone line. After the gas–liquid separation, gas mass will be formed, pocket flow will be readily induced, and the gas block-up phenomenon will result in energy loss in the compression unit. Simulations indicate that the static pressure recovery and total pressure loss in a diffuser fluctuate over time. The static pressure recovery efficacy of the diffuser is highest when the imported gas volume fraction is 10% and lowest when the imported gas volume fraction is 60%. On the surface of the impeller blade, perpendicular to the flow direction, the separation phenomenon near the hub side is more severe than that near the rim. Along the flow direction, the pattern of phase separation is comparable.

Investigation of Gold Recovery and Mercury Losses in Whole Ore Amalgamation: Artisanal Gold Mining in Nambija, Ecuador

Mercury is a highly toxic pollutant that can negatively affect human health and the environment; informal mining is one of the main sources of anthropogenic mercury release due to the separation or concentration by amalgamation that is still used to recover gold directly from ore. In the Nambija mining district, there is still informal mining based on practically no technical knowledge, which uses amalgamation as a processing technique for gold recovery. The production tasks that directly affect the handling of mercury during the in situ grinding–amalgamation process are monitored here. Experimental grinding tests were initially carried out in a “chancha” bar mill for a range of ore sizes and as a function of time; then, experimental tests were performed at the macro-level on grinding cycles in Chilean mills. Considering the characteristics of the ore mineral and the operation of the Chilean mills, it was determined that it is possible to reduce the Hg input to mill by up to 20% (at source). Experimental grinding–amalgamation tests were carried out at different times along with a grain size analysis of the ore; the recovery establishes the grinding time and the fraction in which the gold is extracted in a greater proportion, which affects the control of the amalgamation times. The mercury dosage used by the miners in the amalgamation process should be reduced, considering trials where there is better gold recovery and with the purpose of also reducing mercury losses; eventually, it is possible to jointly achieve an increase in gold recovery.

Layer-by-layer assembled magnetic molecularly imprinted nanoparticles for highly specific separation of adenosine 5′-monophosphate: Relations between adsorption properties and imprinted layers

Molecularly imprinted polymers (MIPs) are an effective method to accurately recognize and isolate targets. Adenosine 5′-monophosphate (AMPs) are typical nucleoside compounds widely used as intermediates and raw materials in the pharmaceutical field with high medicinal potential. In this work, molecularly imprinted adsorbents with fast magnetic response recovery were obtained for the selective separation of AMP by covering MIPs with AcrU and AM as functional monomers and AMP as a template molecule on the surfaces of Fe3O4 NPs, and then by layer-by-layer (LBL) assembling of the MIPs realized through glutaraldehyde (GA) mediation. Static adsorption experiments have been utilized to explore the adsorption effects of different numbers of imprinted layers. The experimental results showed that the Fe3O4@MIPs-LBL2 covered with two layers of MIPs had the best imprinting effect (IF = 2.50), and the adsorption of AMP by Fe3O4@MIPs-LBL2 was dominated by chemisorption, with the saturation adsorption capacity reaching 105.72 μmol g−1, it could adsorb and separate AMP efficiently from the actual sample (human urine). The magnetic responsiveness solves the problem of difficult recovery and high recovery loss of nano-imprinted adsorbents. Notably, this work not only proposes a magnetic imprinted adsorbent for selective separation of AMP, but also explores the structure-effect relationship between the number of layers of MIPs and adsorption performance, which provides a new inspiration for improving the performance of molecular imprinting techniques.

Design Considerations of Multi-Phase Buck DC-DC Converter

The main objective of this article is to propose a rational methodology for designing multi-phase step-down DC-DC converters, which can find applications both in engineering practice and in power electronics education. This study discusses the main types of losses in the multi-phase synchronous buck converter circuit (transistors’ conduction losses, high-side MOSFET’s switching losses, reverse recovery losses in the body diode, dead time losses, output capacitance losses in the MOSFETs, gate charge losses in MOSFETs, conduction losses in the inductor, and losses in the input and output capacitors) and provides analytical dependencies for their calculation. Based on the control examples for applications characterized by low voltage and high output current, the multi-phase buck converter’s output and input current ripples are analyzed and compared analytically and graphically (3D plots). Furthermore, graphical results of the converter efficiency at different numbers of phases (N = 2, 4, 6, 8, and 12) are presented. An analysis of the impact of various parameters on power losses is conducted. Thus, a discussion on assessing the factors influencing the selection of the number of phases in the multi-phase synchronous buck converter is presented. The proposed systematized approach, which offers a fast and accurate method for calculating power losses and overall converter efficiency, reduces the need for extensive preliminary computational procedures and achieves optimized solutions. Simulation results for investigating power losses in 8-phase multi-phase synchronous buck converters are also presented. The relative error between analytical and simulation results does not exceed 4%.

An improved Z-source-derived converter for efficient PV integration

ABSTRACT This paper proposes a high-voltage (HV) gain non-inverting an improved Z-source (ZS)-derived non-isolated boost converter topology. The achievement of HV gain is facilitated through the astute's integration of a ZS, a switched capacitor (SC), and a boost cell that operates with a reduced duty cycle. In comparison with earlier developed topologies, the proposed topology uses fewer components and provides HV gain. In addition to this, the converter reduces voltage stress on semiconductors and passive components. As a result, low-voltage rating (small R ds(on) ) switches and diodes can be used to reduce conduction and reverse recovery losses, respectively. The converter emphasises on reducing device count while increasing device utilisation factor and accommodating a broad range of input variations; thus, it has potential application in HV low-power distributed photovoltaic (PV) systems. Additionally, the converter draws continuous input current from the low-voltage PV terminal. The proposed converter’s operating principle is thoroughly examined in stead state. A 400 W prototype has been developed to verify the operational efficiency and theoretical assertions of the converter, with a switching frequency of 100 kHz. The converter obtained a peak efficiency of 93.25%.

A General Purpose Transformerless Charging System Based on Fully Bridgeless Canonical Switching Cell High-Quality Rectifier for LVEVs

A general purpose transformerless charging system (CS) targeted for various class of low voltage electric vehicles (LVEVs) (24 V–72 V), is designed, analyzed, and implemented in this work. The presented CS employs a fully bridgeless canonical switching cell (FBLCSC) improved power quality rectifier (IPQR) at its front end stage, and a high gain buck (HGB) DC-DC converter at its back end stage. At front end, the presented FBLCSC IPQR does not employ diode bridge rectifier (DBR) circuit, and therefore, ensures better conversion efficiency while operating over wide range of AC mains conditions (110 V–265 V). Further, compared to conventional buck-boost derived IPQRs, the presented IPQR employs minimum component count and maintains low current ripples at its AC and DC ends. On one side, the minimum component count shrinks down the cost, size and losses of the complete CS; low current ripples characteristic on the other side lowers the size of AC and DC end filtering elements. Notably, the FBLCSC IPQR exhibits auto unity power factor operation during discontinuous current mode (DCM) design, and thus, facilitates simple and low cost control architecture. Apart from control simplicity, the DCM operation of FBLCSC IPQR leads to negligible switch turn-on and diode reverse recovery losses. Likewise, at the back end stage, the HGB converter realizes a transformerless DC-DC stage to ensure ripple free charging of different classes of LVEVs. Even if, the HGB DC-DC stage accomplishes transformerless steeper step down gain, its simple design and effective operation over wide battery voltages (24 V–72 V), are further ensured through flexible DC link voltage (150 V – 350 V) control of front end FBLCSC IPQR. At last, the design, operation, and performance of the presented CS are validated experimentally, and relevant results are discussed comprehensively in support of the performance validation of the presented CS.

New insights into the hemodynamics of pulmonary homograft patients under stress echocardiography: The contribution of pressure recovery.

The importance of pulmonary artery pressure recovery (PR) in patients with Ross procedures in whom a homograft substitutes the resected pulmonary valve, is unknown. The aim of the study was to evaluate the occurrence and extent of PR in the pulmonary artery in 65 asymptomatic patients with pulmonary homograft after Ross surgery during rest and exercise. Stress echocardiography was performed in 65 pulmonary homograft patients and 31 controls with native pulmonary valves up to 75W. Right ventricular systolic pressure (RVSP), transvalvular flow, mean pressure gradient (Pmean ), valve resistance, and RV stroke work were determined in the exercise (max. 75W) and recovery phases in increments of 25W each. Pulmonary homografts demonstrated significantly elevated Pmean compared to controls at all stages. When considering pressure recovery (absolute and relative PR at rest 3.8±1.8mm Hg, 42.6±7.2%, respectively) and transvalvular energy loss (EL; at rest 4.5±4.3mm Hg) the homograft hemodynamics reached the level of controls. In a subgroup of patients with tricuspid regurgitation, resting RVSP was the same in homograft patients and controls (21.3±6.1 vs. 20.4±6.3, p=.62), despite significant different Pmax values. Ross patients with pulmonary homograft showed systematically increased hemodynamic parameters compared to normal pulmonary valves. These differences were abolished when PR was considered for homograft patients. The equality of RVSP values at rest in both groups shows non-invasive evidence for PR in the pulmonary system after homograft implantation. Therefore, PR appears to be an important measure in calculating the actual hemodynamics in pulmonary homografts.

Low-light image enhancement based onRetinex-Net with color restoration.

Low-light images often suffer from a variety of degradation problems such as loss of detail, color distortions, and prominent noise. In this paper, the Retinex-Net model and loss function with color restoration are proposed to reduce color distortion in low-light image enhancement. The model trains the decom-net and color recovery-net to achieve decomposition of low-light images and color restoration of reflected images, respectively. First, a convolutional neural network and the designed loss functions are used in the decom-net to decompose the low-light image pair into an optimal reflection image and illumination image as the input of the network, and the reflection image after normal light decomposition is taken as the label. Then, an end-to-end color recovery network with a simplified model and time complexity is learned and combined with the color recovery loss function to obtain the correction reflection map with higher perception quality, and gamma correction is applied to the decomposed illumination image. Finally, the corrected reflection image and the illumination image are synthesized to get the enhanced image. The experimental results show that the proposed network model has lower brightness-order-error (LOE) and natural image quality evaluator (NIQE) values, and the average LOE and NIQE values of the low-light dataset images can be reduced to 942 and 6.42, respectively, which significantly improves image quality compared with other low-light enhancement methods. Generally, our proposed method can effectively improve image illuminance and restore color information in the end-to-end learning process of low-light images.

A non‐isolated DC‐DC topology with high voltage rate based on magnetic coupling and voltage multiplier method

SummaryIn this study, a novel non‐isolated DC‐DC converter based on magnetic coupling and voltage multiplier technique has been proposed. The output voltage of the suggested converter can be enhanced by selecting the appropriate turn ratio of the coupled inductor. To further improve the voltage gain, a voltage multiplier circuit including the capacitors and diodes has been utilized in this converter. The main features of the proposed converter are a high voltage conversion ratio, high efficiency, and lower peak voltage throughout the semiconductor devices. Besides, there are soft switching conditions throughout the diodes of the presented topology, which leads to reducing the reverse recovery losses of the diodes and subsequently improving the overall efficiency of the system. Also, only one insulated‐gate field‐effect transistor (MOSFET) has been used in the structure of the converter. Thus, the switch with lower on‐state resistance can be selected for the suggested converter that decreases the conduction losses. To prove the performance of the suggested structure, the operational analysis, mathematical descriptions, efficiency analysis, and comparison survey with similar structures in the literature have been described. Finally, a laboratory prototype with 200 W output power with 95.14% load efficiency, 20 V input voltage, and 260 V output voltage at 50 kHz switching frequency has been provided.

Multi-scale techno-economic assessment of nitrogen recovery systems for livestock operations

Intensive livestock farming generates vast amounts of organic materials, which are an important source of nitrogen releases. These anthropogenic nitrogen releases contribute to multiple environmental problems, including eutrophication of water systems, contamination of drinking water sources, and greenhouse gas emissions. Nitrogen recovery and recycling are technically feasible, and there exists a number of processes for nitrogen recovery from livestock material in the form of different products. In this work, a multi-scale techno-economic assessment of techniques for nitrogen recovery and recycling is performed. The assessment includes a material flow analysis of each process, from material collection to final treatment, to determine nitrogen recovery efficiency, losses, and recovery cost, as well as an environmental cost-benefit analysis to compare the nitrogen recovery cost versus the economic losses derived from its uncontrolled release into the environment. The results show that transmembrane chemisorption process results in the lowest recovery cost, 3.4-10.4 USD per kilogram of nitrogen recovered in the range of studied processing scales. The recovery of nitrogen from livestock material through three technologies, i.e., transmembrane chemisorption, MAPHEX, and stripping in packed bed, reveales to be cost-effective. Since the economic losses due to the harmful effects of nitrogen into the environment are estimated at 32-35 USD per kilogram of nitrogen released, nitrogen recycling is an environmentally and economically beneficial approach to reduce nutrient pollution caused by livestock operations.

A Single-Stage Charger for LEV Based on Quadratic Buck-Boost AC-DC Converter Topology

A single-stage AC-DC converter, which uses a quadratic buck-boost voltage gain, for LEVs' (Light Electric Vehicles) battery charging is presented in this work. Unlike conventional BCs (Battery Chargers), which employ transformer (low or high frequency) based approaches to charge low voltages LEVs' batteries, the presented charger utilizes transformerless single-stage power architecture. In order to realize desired charging of LEVs and to maintain proper transformerless voltage gain, the presented quadratic buck-boost AC-DC converter ensures high step-down gain characteristics between AC mains and low voltage battery packs. Besides realizing desired battery charging profile, the presented single-stage BC ensures high PQ (Power Quality) indices (low input current distortions and unity power factor operation) at the supply side. Notably, the presented quadratic buck-boost AC-DC converter exhibits an intrinsic power factor correction (PFC) feature at the AC input mains under discontinuous inductor current mode (DICM) operation, thereby, incurring minimum complexities during the control implementation, which further reduces the cost of the charger. The DICM operation facilitates negligible switch turn-on and diode reverse recovery losses, and therefore, ensures an improved conversion efficiency of the BC. Even if, the presented AC-DC converter employs two switching devices, the simultaneous switching of both switches shrinks the cost and complexity of driving circuitry even further. Finally, a comprehensive operational analysis, component selection criteria, and modelling of the presented quadratic buck-boost AC-DC converter-based LEVs BC are carried out and its performance is validated through a test bench set-up in a laboratory environment. Relevant results are presented to validate the efficacy of the presented quadratic buck-boost AC-DC converter for LEVs charging applications.

Pathway to Prediction of Pyrite Floatability from Copper Ore Geological Domain Data

The depletion of mining resources forces the mining industry to process more heterogeneous and complex orebodies. The inherent heterogeneity of these orebodies and their relation to processing recoveries have received considerable interest in recent years. The properties of ores, such as mineral composition and association, are known to affect flotation performance. Even ores with similar compositions can vary significantly regarding their texture, where the same minerals can occur in different forms. Therefore, very careful geometallurgical planning is needed to overcome the recovery losses. Glencore’s Mount Isa Copper Operation has reported historical difficulties decreasing the copper losses associated with natural floatable pyrites. Understanding the rock properties of naturally floatable pyrites and how they relate to chalcopyrite losses is crucial for concentrator operations. The Mount Isa geometallurgy team is looking for proxies for predicting copper losses and natural floatable pyrites to improve mine planning. This paper presents an approach for predicting the collector-less flotation of pyrite, as well as chalcopyrite losses from rock properties. The statistical analysis between the rock quality and ore type gives an indication of the chalcopyrite losses and natural floatable pyrites, which has potential use in geometallurgy plans.

3D directional gradient L0 norm minimization guided limited-view reconstruction in a dual-panel positron emission mammography

BackgroundDual-panel PET is often used for local organ imaging, especially breast imaging, due to its simple structure, high sensitivity, good in-plane resolution, and straightforward fusion with other imaging modalities. Nevertheless, because of data loss caused by the dual-panel structure, using conventional image reconstruction methods results in limited-view artifacts and low image quality in dual-panel positron emission mammography (PEM), which may seriously affect the diagnosis. To mitigate the limited-view artifacts in the dual-panel PEM, we propose a 3D directional gradient L0 norm minimization (3D-DL0) guided reconstruction method. MethodsThe detailed derivation and reasonable simplification of the 3D-DL0 algorithm are given first. Using this algorithm, we then obtain a prior image with edge recovery but contrast loss. To limit the solution space, the 3D-DL0 prior is introduced into the Maximum a Posteriori reconstruction. Meanwhile, a space-invariant point spread function is also implemented to restore image contrast and boundaries. Finally, the reconstructed images with limited-view artifact suppression are obtained. The proposed method was evaluated using the data acquired from physical phantoms and patients with breast tumors on a commercial dual-panel PET system. ResultsThe qualitative and quantitative studies for phantom data and the blind reader study for clinical data show that the proposed method is more effective in reaching a balance between artifact elimination and image contrast improvement compared with various limited-view reconstruction methods. In addition, the iteration process of the method is proved convergent numerically. ConclusionsThe image quality improvement confirms the potential value of the proposed reconstruction algorithm to address the limited-view problem, and thus improve diagnostic accuracy in dual-panel PEM imaging.

A Novel Shield Gate 4H-SiC MOSFET with Reduced Reverse Recovery Losses

In this work, a novel integrated shield gate 4H-SiC MOSFET structure, which is mainly used to reduce the reverse recovery losses of the device, is proposed. Compared with integrating Schottky barrier diode or heterojunction diode in the device to reduce reverse recovery losses, the technology of introducing field plates in MOSFETs is more mature and economical. At the same time, the new structure studied ensures the gate oxide reliability of the 4H-SiC trench gate. According to the simulation of the electrical characteristics of the source-contacted shield gate device, the effects of multiple factors such as electric field distribution, carrier concentration, and peripheral circuit are comprehensively discussed, the phenomenon of smaller reverse recovery losses caused by the shield gate explained in detail. Compared with the conventional structure device, the peak reverse current, the peak overshoot voltage, and the reverse recovery losses for the source-contacted shield gate MOSFETs are reduced by 81.4%, 77.1%, and 65.1%, respectively.

Knowledge and eating habits of CrossFit trainees

Introduction. Achieving high performance in sports is the result of many factors, both exo and endogenous. Proper nutrition is the basis of the so-called healthy lifestyle, health care and prevention of diet-related diseases. Physical activity is an extremely important component and carries a number of benefits that affect mental, physical and social well-being. Failure to provide sufficient energy, can lead to decreased performance, delayed recovery processes or loss of muscle mass. The purpose of the study was to assess the knowledge and nutritional habits of CrossFit trainees.
 Material and methods. 131 people were surveyed; the questionnaire was posted on the CrossFit Poland forum. The survey was voluntary and anonymous. The results were collected in a database in Microsoft Excel 2010 MS Office Package and statistically analyzed using Statistica 12. In the statistical evaluation of the relationship between characteristics, a significance level of p ≤ 0.05 was adopted. Results. In a survey of the knowledge and eating habits of CrossFit trainees, about 50% of respondents declare that they eat regularly. In addition, 50.5% state a moderate level of knowledge about healthy eating, while 33% state a high level. There is a high incidence of dietary supplement intake, accounting for 78.5%. As the frequency of training increases, the amount of supplements consumed increases. Conclusions. A significant part of the study group declares a very good or moderate level of knowledge of rational nutrition, which influences the choice of and regularity of the meals consumed in this group of Crossfit trainers.

Analysis and Design of a New High Voltage Gain Interleaved DC–DC Converter with Three-Winding Coupled Inductors for Renewable Energy Systems

In this article, a new non-isolated interleaved DC–DC converter is proposed to provide a high voltage conversion ratio in renewable energy systems. The converter configuration is composed of a two-phase interleaved boost converter integrating a voltage-lift capacitor and three-winding coupled inductor-based voltage multiplier modules to achieve high step-up voltage conversion and reduce voltage stresses on the semiconductors (switches and diodes). The converter can achieve a high voltage conversion ratio when working at a proper duty ratio. The voltage stresses on the switches are significantly lower than the output voltage, which enables engineers to adopt low-voltage-rating MOSFETs with low on-state resistance. The switches can turn on under zero-current switching (ZCS) conditions because of the leakage inductor series reducing switching losses. Some diodes can naturally turn off under ZCS conditions to alleviate the reverse–recovery issue and to reduce reverse–recovery losses. The input current has small ripples due to the interleaved operation. The leakage inductor energy is recycled and voltage spikes on the switches are avoided. The proposed converter is suitable for applications in which high voltage gain, high efficiency and high power are required. The principle of operation, steady-state analysis and design considerations of the proposed converter are described in detail. In addition, a closed-loop controller is designed to reduce the effect of input voltage fluctuation and load change on the output voltage. Finally, a 1000 W laboratory prototype is built and tested. The theoretical analysis and the performance of the proposed converter were validated by the experimental results.

Nano-microbubbles and feed size interaction in lead and zinc sulfide minerals flotation

Low recovery of the fully or highly liberated fine particles to the concentrate, and consequently, valuable loss to the tailing is a challenge of flotation industry, majorly due to the low probability of bubble-particle collision. Bubble size significantly affects the efficiency of collision. In this study, the effect of nano-micro bubbles and feed particle size (d80s in the range of 80 to 12 µm), on the lead and zinc minerals recovery, separation efficiency, and valuables loss to the tailings were investigated. The presence of NMBW simultaneously improved concentrate grade and metal recovery to the individual concentrates. Over 14.5% improvements in either lead and zinc recoveries, 0.95% and 2.22% enhancement in lead and zinc concentrate grades, and 15.6% and 8.9% increases in lead and zinc separation efficiencies were, respectively, gained. The application of NMBW, however, reduced metal loss to the tailings, more evident for the finest feed (order based on d100: -38>-75>-106 µm). By increasing NMBW content to 100% of the pulp water, the metal loss to the tailing for the dry-ground feed with the d80 of 12 µm, was decreased from 80.4% to 65.9% in the lead flotation, and from 54.9% to 43.2% in the zinc flotation.

Low Switching Loss Built-In Diode of High-Voltage RC-IGBT with Shortened P+ Emitter

In this paper, a low switching loss built-in diode of a high-voltage reverse-conducting insulated gate bipolar transistor (RC-IGBT) is proposed without deteriorating IGBT characteristics. It features a particular shortened P+ emitter (SE) in the diode part of RC-IGBT. Firstly, the shortened P+ emitter in the diode part can suppress the hole injection efficiency resulting in the reduced carriers extracted during the reverse recovery process. The peak of the reverse recovery current and switching loss of the built-in diode during reverse recovery is therefore lowered. Simulation results indicate that the diode’s reverse recovery loss of the proposed RC-IGBT is lowered by 20% compared with that of the conventional RC-IGBT. Secondly, the separate design of the P+ emitter prevents the performance of IGBT from deteriorating. Finally, the wafer process of the proposed RC-IGBT is almost the same as that of conventional RC-IGBT, which makes it a promising candidate for manufacturing.

A Novel High-Voltage Gain Step-Up DC–DC Converter with Maximum Power Point Tracker for Solar Photovoltaic Systems

In order to generate electricity from solar PV modules, this study proposed a novel high-voltage gain step-up (HVGSU) DC–DC converter for solar photovoltaic system operation with a maximum power point (MPP) tracker. The PV array can supply power to the load via a DC–DC converter, increasing the output voltage. Due to the stochastic nature of solar energy, PV arrays must use the MPPT control approach to function at the MPP. This study suggests a novel HVGSU converter that uses the primary boost conversion cell and combines switched capacitors and voltage multiplier cells. The proposed topology is upgradeable for high-voltage gain step-up and can be incorporated as well. A clamp circuit reuses the energy that leaks out so that the switch voltage stress and power loss are kept to a minimum. One thing that makes it stand out is that the voltage stress on the diodes and switch stays low and constant even as the duty cycle changes. Additionally, the inductor greatly reduces the diodes’ reverse recovery losses. There is a lot of information about steady-state analyses, operation principles, and design guidelines. A prototype circuit is built to test the maximum power point tracking operation with voltage conversion from 20–40 V to 380 V at 150 W. The results of the experiments support the theoretical analysis and claimed benefits. The proposed converter has the ability to track the maximum power point and a high conversion efficiency over a wide range of power. A weighted efficiency of 90–96% is shown by the prototype.

Coupled Inductor-Based Single-Switch Quadratic High Step-Up DC–DC Converters With Reduced Voltage Stress on Switch

In this article, two single-switch quadratic boost converters based on a three-winding coupled inductor (CI) are proposed. These converters provide a high voltage gain in a low duty cycle, reduced voltage stress on the power switch, continuous input current with a low <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">di/dt,</i> higher design flexibility, and limited current falling rate on the voltage multiplier diodes to minimize the reverse recovery loss. Moreover, the first proposed converter has two capacitors in the output reducing the need for a bulky output capacitor, while the second proposed converter has higher utilization of the CI and is able to provide a higher voltage gain. The operation principle and theoretical analysis, such as voltage stress, current stress, effect of leakage inductances on the voltage gain, and design considerations are presented in this article. Furthermore, the superiority of the proposed converters over the competitive high step-up quadratic converters are justified through a comparison study. Finally, a 300-W, 30- to 400-V laboratory experimental setup is implemented to validate the theoretical analysis.