Traditional Configuration Research Articles

Enhancement of power output of partially shaded photovoltaic system using optimal Sudoku puzzle based triple-tied-cross-link reconfiguration techniques

Partial shade on a photovoltaic (PV) array reduces output power because of mismatch losses. Therefore, selection of PV array configuration is one of the crucial factors to consider for maximum power output. The Triple-Tied-Cross-Link (TTCL) configuration used has lesser tied connection in contrast to the conventional Total-Cross-Tied (TCT) configuration. The performance oSf the TTCL configuration is further enhanced by applying Sudoku puzzles as a reconfiguration technique. Without changing the electrical connection, the Sudoku puzzle is used to arrange the physical placement of the modules in the PV arrays. By dispersing the shading impact over the array, the suggested arrangement reduces the amount of shade that dominates in any one row. The recommended Optimal Sudoku Puzzle (OSP)- based TTCL design’s performance has been compared to the TTCL setup for the 9 × 9 PV array. Six partial shading patterns named Group-I to Group-VI are considered to analyze the performance of the proposed reconfiguration technique. The number of parameters such as global maximum power point (GMPP), open circuit voltage, short circuit current, mismatch loss, fill factor, and efficiency are measured to show its performance under different shading patterns. The numerical results show the effectiveness of the recommended OSP- based TTCL configuration technique. It is investigated that the numerical values in the case of shading pattern Group-III for the performance parameter GMP and fill factor have increased by 11.59% and 16.90 %, respectively, as compared to TTCL configuration. The mismatch loss (ML) was achieved with the lowest value, i.e., 21.98%, when compared to the TTCL (36.13%). The 9 × 9 PV array’s efficiency in the proposed configuration is 13.33%, which is higher than that of TTCL (11.94%) arrangements. From the simulated results, the puzzle-based reconfiguration technique is found to be an optimal approach as compared to traditional configuration.

Additive Manufacturing of Liquid-Cooled Ceramic Heat Sinks: An Experimental and Numerical Study

With recent advances in power electronic packaging technologies, liquid-cooled ceramic heat sinks have been considered as a promising solution for further improving the performance of power electronic devices. In this study, several aluminum oxide heat sinks were fabricated and tested using the digital light processing-based additive manufacturing method, to verify their practical performance. The results showed that the complex cooling structures inside the heat sinks can be completely formed and exhibited high surface quality. The experimental thermal and hydraulic performances of the heat sinks were consistent with the numerically modeled predictions. Furthermore, by exploiting the advantages of additive manufacturing, a direct manifold microchannel (MMC) configuration was designed to reduce the vertical flow of the traditional MMC configuration and achieve an improved cooling efficiency. At a constant volumetric flow rate of 1 L/min, the direct MMC configuration achieved a 19.8% reduction in pressure drop and an 11.8% reduction in thermal resistance, as well as a more uniform temperature distribution.

Asymmetric magnetic levitation for density-based measurement and analysis

BackgroundMagnetic levitation (MagLev) based on negative magnetophoresis represents a promising technology for density-based analysis and manipulation of nonmagnetic objects. This approach has garnered considerable interest across multiple fields, such as chemistry, materials science, and biochemistry, primarily due to its inherent simplicity, precision, and cost-effectiveness. However, it is essential to recognize that frequently used MagLev configurations, including standard MagLev and axial MagLev, are not without their limitations. These configurations often struggle to strike a balance between levitation performance, ease of operation, and visibility. Therefore, it is necessary to develop a new MagLev configuration to address the aforementioned issue. ResultsThis work describes the development of an innovative MagLev, termed “asymmetric MagLev”, achieved by combining a ring magnet and a cylinder magnet as up-down asymmetric magnetic field sources. The asymmetric design overcomes the physical obstacles along the centerline of the standard MagLev, offering unique open-structure advantages, including easy handling of samples, the ability to observe samples from the top or bottom, and no restrictions on the container height. Meanwhile, comparative analysis reveals a considerable enhancement in the working distance of the asymmetric MagLev without significantly sacrificing the measurement range compared to the axial MagLev. Notably, the asymmetric MagLev achieves a remarkable sensitivity of up to about 1.8 × 104 mm (g cm−3)−1, surpassing the axial MagLev by approximately 30 times. Furthermore, experimental results validate the successful application of the asymmetric MagLev in density measurement and quality detection of small-sized objects. SignificanceThis pioneering configuration represents the first utilization of up-down asymmetric magnets in the field of MagLev. Through the integration of an axially magnetized ring magnet and a cylinder magnet, the asymmetric MagLev design overcomes the limitations associated with conventional MagLev configurations. This innovative design exhibits outstanding operational capabilities and levitation performance, making it suitable for a wide range of applications in density-based measurement and analysis.

Performance analysis of a permanent magnet synchronous motor with dual stator windings

This paper presents the modelling and performance analysis of a line-start three-phase interior permanent magnet synchronous motor (IPMSM) with dual stator windings. The machine has two sets of windings, main and auxiliary windings. The main winding is connected to the supply while the auxiliary is connected to a balanced capacitor. The dynamic model equations are derived in the d-q rotor reference frame using the concept of winding function theory. The machine input impedance was construed from the steady-state equations, where the effects of capacitance on the performance of the motor were studied. An improved torque was obtained when a suitable capacitance was connected to the auxiliary winding. A point of good performance was established by enhancing its direct axis reactance and the quadrature axis reactance which depend on the size of the capacitor. It is shown that thenew configuration has better performance characteristics when compared with those of the traditional configuration in terms of output power, torque density and efficiency.

Assessment of centralised and localised ice cream supply chains using neighbourhood flow configuration models

Traditional food supply chains are often centralised and global in nature, entailing substantial resource consumption. However, in the face of growing demand for sustainability, this strategy faces significant challenges. Adoption of localised supply chains is deemed a more sustainable option, yet its efficacy requires verification. Supply chain analytics methodologies provide invaluable tools to guide decisions regarding inventory management, demand forecasting and distribution optimisation. These solutions not only enhance facilitate operational efficiency, but also pave the way for cost reduction, further aligning with sustainability objectives. This research introduces a novel decision-making approach anchored in mixed integer linear programming (MILP) and neighbourhood flow models defined in cellular automata to compare the environmental benefits and vulnerability to disruption of these two chain configurations. Additionally, a comprehensive cost analysis is integrated to assess the economic feasibility of incorporating layout changes that enhance supply chain sustainability. The proposed framework is applied on an ice cream supply chain across England over a one-year timeframe. The findings indicate the superiority of the localised configuration in terms of economic benefits, leading to savings exceeding £ 1 million, alongside important reductions in environmental impact. However, in terms of resilience, the traditional configuration remains superior in three out of the four examined scenarios.

EXPERIMENTAL THERMAL PERFORMANCE ANALYSIS OF NANOFLUID ASSISTED SLINKY GROUND HEAT EXCHANGER IN SPACE COOLING APPLICATION

Ground source heat pump has made a severe breakthrough in space conditioning applications due to their high energy efficiency, and expectations for these systems have increased due to using renewable energy. Concerning the increasing expectation, researchers and engineers have increased their research on these systems and focused on cost and efficiency. The efficiency of the ground source heat pump system is directly related to the ground heat exchanger loop, which provides the thermal connection between the heat pump and the ground, and increasing the effectiveness of the ground heat exchanger can be achieved with a nanofluid-based heat transfer fluid. On the other hand, as a ground source heat pump system component, ground heat exchangers have very different design configurations. Among the various configurations, slinky ground heat exchangers are of great interest due to their higher heat transfer efficiency and reduced installation space requirements compared to traditional straight pipe configurations. In this study, the effect of nanofluids on increasing the effectiveness of slinky ground heat exchangers was experimentally investigated and compared with the results obtained using conventional heat transfer fluids. The results obtained from the experimental study determined that using nanofluid at a rate of 0.1% as a heat transfer fluid in slinky ground heat exchangers in cooling applications increased the average effectiveness by about 20%.

PH Quantification in Human Dermal Interstitial Fluid Using Ultra-Thin SOI Silicon Nanowire ISFETs and a High-Sensitivity Constant-Current Approach.

In this paper, we propose a novel approach to utilize silicon nanowires as high-sensitivity pH sensors. Our approach works based on fixing the current bias of silicon nanowires Ion Sensitive Field Effect Transistors (ISFETs) and monitor the resulting drain voltage as the sensing signal. By fine tuning the injected current levels, we can optimize the sensing conditions according to different sensor requirements. This method proves to be highly suitable for real-time and continuous measurements of biomarkers in human biofluids. To validate our approach, we conducted experiments, with real human sera samples to simulate the composition of human interstitial fluid (ISF), using both the conventional top-gate approach and the optimized constant current method. We successfully demonstrated pH sensing within the physiopathological range of 6.5 to 8, achieving an exceptional level of accuracy in this complex matrix. Specifically, we obtained a maximum error as low as 0.92% (equivalent to 0.07 pH unit) using the constant-current method at the optimal current levels (1.71% for top-gate). Moreover, by utilizing different pools of human sera with varying total protein content, we demonstrated that the protein content among patients does not impact the sensors' performance in pH sensing. Furthermore, we tested real-human ISF samples collected from volunteers. The obtained accuracy in this scenario was also outstanding, with an error as low as 0.015 pH unit using the constant-current method and 0.178 pH unit in traditional top-gate configuration.

Large-Signal Stability of the Quadratic Boost Converter Using a Disturbance Observer-Based Sliding-Mode Control

The quadratic boost (QB) converter is a fourth-order system with a dc gain that is higher than the traditional second-order step-up configuration. The modern controllers that control these high-order dc–dc converters often only guarantee local stability around a steady-state equilibrium point, which is one of their primary drawbacks. In this article, a non-linear robust control law design to attain large-signal stability in this single switch QB converter is presented. In the presence of an unpredictable load, the control objective is to maintain the regulation of an output voltage. The Brunovsky canonical model of the converter was derived first, and the non-linear disturbance observer-based sliding-mode (SM) control law is designed based on it. An observer variable precisely estimates the output disturbances. The detailed process for deriving the control signal is described in this paper and the large-signal stability of the closed-loop converter system is ensured via the Lyapunov function. Finally, some simulation results are shown to validate the usefulness of the given controller.

Measuring the impact of SR-IOV and virtualization on packet round-trip time

This article explores different data plane configurations for data center servers, focusing on scenarios involving SR-IOV in conjunction with KVM virtualization. Specifically, it evaluates the performance of different ways of using SR-IOV, including MacVTap “passthrough” mode with SR-IOV and PCI Passthrough on the Linux data plane. The study aims to shed light on how SR-IOV can be leveraged to optimize round-trip time (RTT) and resource usage. Through the experiments, we confirmed the expected behaviors of the technology but also clarified and identified behavioral aspects not yet known. For example, we confirmed that SR-IOV could improve RTT and outperform more traditional configurations, but we identified that this comes at the price of utilizing more computational resources, such as the CPU, depending on the orchestrated usage configuration. Furthermore, our evaluations also found that configuring the SR-IOV MacVTap in “passthrough” mode appears to be the best configuration when CPU resources are scarce or low or when scalability and flexibility are design requirements. In this article, we also expanded the SR-IOV assessment regarding the concurrency of this feature. Through these assessments, we identified that a VM without SR-IOV in a data center with other VMs that benefit from SR-IOV is inefficient from a performance point of view of communication. Thus, in this way, this study provides valuable information on how to optimize the use of SR-IOV in KVM environments to design efficient and high-performance virtualized data centers.

Power-oriented resistance training combined with high-intensity interval training in pre-frail and frail older people: comparison between traditional and cluster training set configurations on the force–velocity relationship, physical function and frailty

ObjectivesTo analyse the force–velocity relationship changes in response to two different training programmes differing in the set configuration (cluster vs. traditional), and their impact on physical function and frailty in pre-frail and frail older adults.Methods43 pre-frail and frail (Frailty Phenotype ≥ 1 criteria) older adults (81.4 ± 5.1 years) participated in this study. Participants were assigned to cluster (CT; n = 10; 10-s intra-set rest), traditional (TT; n = 13; no intra-set rest) or control (CON; n = 20) groups. Force–velocity relationship (F0, V0 and Pmax), physical function (Short Physical Performance Battery, SPPB) and frailty (Frailty Phenotype, FP) were assessed at baseline and after the training programme.ResultsBoth CT and TT groups showed similar improvements in Pmax after training (CT = + 36.7 ± 34.2 W; TT = + 33.8 ± 44.6 W; both p < 0.01). V0 was improved by both CT (+ 0.08 ± 0.06 m s−1; p < 0.01), and TT (+ 0.07 ± 0.15 m s−1, p > 0.05). F0 remained unchanged in CT (+ 68.6 ± 224.2 N, p > 0.05) but increased in TT (+ 125.4 ± 226.8 N, p < 0.05). Finally, SPPB improved in both training conditions (CT = + 2.3 ± 1.3 points; TT = + 3.0 ± 1.2 points; both p < 0.05) and in the CON group (+ 0.9 ± 1.4 points, p < 0.05). CT and TT reduced their FP (CT = − 1.1 criteria; TT = − 1.6 criteria; both p < 0.01), while no changes were observed in the CON group (− 0.2 criteria, p = 0.38).ConclusionsBoth training methods were equally effective for improving Pmax, physical function and reducing frailty in pre-frail and frail older people. TT may be effective for improving both force and velocity parameters, while CT may be effective for improving velocity parameters alone, although further research is required to confirm these findings.

Operational optimisation of integrated campus energy systems considering integrated demand response

Against the backdrop of the rapid development of the energy internet in the park, the multi energy coupling and complementary characteristics of integrated energy systems provide more space for optimizing the participation of demand parties in their coordinated planning. Establishing a effective demand side model with multiple energy flows and response types has become an effective means to improve system performance. For this reason, this paper takes the comprehensive energy system of the park with multiple electricity, gas, heat and cold complements as the research object, establishes a complete model of multi load and multi type demand response based on the improvement, incentive and substitution of real-time pricing mechanism, and uses multi-attribute decision-making method to obtain the optimal configuration of the system by establishing an optimization framework for iteration of the main problem and sub problem. The simulation results show that compared with traditional energy supply system configurations, the complete model established in this paper for various controllable resources on the demand side achieves the coordinated and complementary operation of the system’s multi energy and low-carbon economy, fully utilizing the regulatory potential of the demand side, effectively reducing load fluctuations and energy supply costs.

Characterization of plant growth promoting potential of 3D-printed plant microbial fuel cells

Plant-Microbial Fuel Cell (PMFC) is an emerging technology that converts plant waste into electrical energy through rhizodeposition, offering a renewable and sustainable source of energy. Deviating from the traditional PMFC configurations, additive manufacturing was utilized to create intricate and efficient designs using polymer-carbon composites. Concerning the agricultural sector, the effect of 3D-printed PMFCs on the growth and biomass distribution of Phaseolus lunatus and Ipomoea aquatica was determined. The experiment showed that electrostimulation promoted the average daily leaf number and plant height of both polarized plants, which were statistically proven to be greater than the control (α = 0.05), by energizing the flow of ions in the soil, boosting nutrient uptake and metabolism. It also stimulated the growth of roots, increasing the root dry mass of polarized plants by 155.44% and 66.30% for I. aquatica and P. Lunatus against their non-polarized counterpart. Due to the biofilm formation on the anode surface, the number of root nodules of the polarized P. lunatus was 51.30% higher than the control, while the protein content in the PMFC setup was 42.22% and 8.26% higher than the control for I. aquatica and P. lunatus, respectively. The voltage readings resemble the plants' average growth rate, and the polarization studies showed that the optimum external resistances in the I. aquatica- and P. lunatus-powered PMFC were 4.7 kΩ and 10 kΩ, respectively. Due to other prevailing pathways of organic carbon consumption, such as methanogenesis, the effect of polarization on the organic carbon content in soil is currently inconclusive and requires further study.

Sparse SiPM Pixel Arrangement for a TOF-PET Detector Design that Achieves 100 ps Coincidence Time Resolution

Coupling silicon photomultipliers (SiPMs) to the side of a long and narrow scintillation crystal elements offers near-complete light extraction efficiency, independent of 511 keV photon interaction depth, and reduced scintillation light transit time jitter in its path toward the photodetector. With these advantages, significant improvements in PET detector coincidence time resolution (CTR) can be achieved compared to the traditional scintillation light readout configuration where an SiPM is coupled on the narrow end of crystals. Moreover, the arrangement of photosensors along the crystal’s side intrinsically provides a three-dimensional position sensing detector. One consideration for the side readout approach is the increase in the number of SiPMs required to read each crystal element. In this work, we investigate the achievable CTR when the number of SiPM elements coupled to the side of crystals is parametrically varied, including different crystal lengths and reflector configurations. A simulation model for CTR was validated against measurements with 3-20 mm length crystals employing side readout of scintillation light. The validated simulation model was used to parametrically investigate twenty-seven configurations of SiPMs arranged along the side of crystal elements. Reflector and sensor placement was parametrically varied to find configurations that optimize light collection efficiency, energy resolution, and CTR. One configuration achieved 101±1 ps FWHM CTR, while maintaining high light collection efficiency and good energy performance with a 33% reduction in photosensor area.

A Systematic Approach to Restoring Full Arch Length with Maxillary Fixed Implant Reconstruction: The PATZi Protocol.

The traditional configuration of four maxillary implants to restore full-arch maxillary fixed implant prostheses is not without pitfalls. Intraoperative variability, such as bone quality and quantity, may lead to unexpected intraoperative challenges that may not allow for execution of the original treatment plan. Additionally, extensive maxillary sinus pneumatization may inhibit posterior spread and lead to a shortened dental arch or excessive cantilever forces. The PATZi protocol is a systematized algorithm for maxillary full-arch implant treatment planning that addresses such intraoperative surprises and achieves full arch length in the planned prosthesis. PATZi also assigns a numbering classification to each implant configuration, which leads to uniform communication and grading of surgical difficulty, as well as predictable planning for developing future salvage plans. By using the PATZi protocol as a guideline, the surgeon may improve composite torque value and anteroposterior (AP) spread, eliminate distal cantilever forces, and ultimately improve the predictability of the prosthetic treatment plan.

Enhancing the performance of water-based PVT collectors with nano-PCM and twisted absorber tubes

The study investigated the thermal performance of a photovoltaic thermal (PVT) collector with a twisted absorber tube and nanoparticle-enhanced phase change material (nano-PCM). The PVT collector consisted of twisted absorber tubes, a container filled with nano-PCM, and a photovoltaic (PV) panel. To assess its efficiency, five different configurations were tested using an indoor solar simulator. The configurations analyzed were as follows: (a) an unenhanced PV panel, (b) PVT with circular absorber tubes (C-PVT), (c) PVT with twisted absorber tubes (T-PVT), (d) C-PVT with nano-PCM (C-PVT-PCM), and (e) T-PVT with nano-PCM (T-PVT-PCM). The thermal, photovoltaic, and combined photovoltaic-thermal efficiencies were evaluated at varying mass flow rates (0.008-0.04kg/s) and a constant solar irradiance of 800W/m2. Among the configurations tested, the T-PVT-PCM configuration demonstrated the highest performance. Specifically, at a mass flow rate of 0.04kg/s, solar irradiance of 800W/m2, and an ambient temperature of 27°C, it achieved photovoltaic, thermal, and combined photovoltaic-thermal efficiencies of 9.46%, 79.40%, and 88.86%, respectively. The utilization of twisted absorber tubes in the design notably improved thermal efficiency by enhancing heat transmission between the liquid and the tube surface. Furthermore, the implementation of T-PVT-PCM led to a significant reduction in surface temperature. Compared to the unenhanced PV panel, it lowered the surface temperature by approximately 30°C, and when compared to C-PVT-PCM, it reduced it by around 10°C. Notably, T-PVT-PCM outperformed the unenhanced PV panel by exhibiting a 34.5% higher photovoltaic efficiency. Overall, the study highlights the performance of the PVT collector with twisted absorber tubes and nanoparticle-enhanced phase change material. The innovative design achieved remarkable thermal efficiency, reduced surface temperatures, and significantly enhanced photovoltaic efficiency compared to traditional configurations. These findings contribute to the development of more efficient and versatile solar energy systems with the potential for broader applications in renewable energy technology.

Recovering breeze energy based on galloping enhancement mechanism for smart agriculture

Smart agriculture contributes to a sustainable society. Aiming to provide a self-powered solution for widely distributed sensor nodes in smart agriculture, this work proposes a piezoelectric galloping energy recovery system to recover multi-directional breeze energy in the environment. A galloping enhancement mechanism consisting of an optimal curved-sheet bluff body with a magnet-based bi-stable mechanism is constructed to enhance the energy output from the breeze. Breeze energy recovery is realized by a piezoelectric energy harvester utilizing galloping vibration. Aerodynamic simulations were performed to determine the optimal wide-arc ratio for the curved-sheet bluff body. The magnet-based bi-stable mechanism of three different configuration modes was analyzed and compared. The results of wind tunnel experiments show that the proposed energy recovery system can enhance output power compared to the traditional linear configuration under a breeze. The maximum output power and power growth are 2.81 mW and 49.5 % at 5 m/s wind speed, and a maximum output power increase of 673.3 % was achieved at 3.5 m/s wind speed. The feasibility of powering a low-power agricultural sensor was evaluated in an outdoor experiment. The energy recovery system will effectively manage multi-directional breeze energy recovery, achieving self-powered applications in smart agriculture.

Comparison of non-reactive flow fields in conventional swirl-air combustion and swirl distributed combustion

Flow field distribution in traditional swirl flow and simulated distributed reaction swirl flow configuration was examined at 3 kHz frequency using high-speed Particle Image Velocimetry (PIV). Non-reactive flow field conditions in distributed reaction zones were fostered from the conventional swirl flow case using the designed inlet mixture preparation with CO2 dilution of the inlet airstream that corresponded to the combustion case at a heat release intensity of 5.72 MW/m3-atm. High-speed imaging of flow fields was performed at a framing rate of 3000 frames/s using a Neodymium-doped Yttrium Lithium Fluoride (Nd:YLF) laser beam at 527 nm wavelength to capture the Mie scattering images of the flow field. Mean flow velocity obtained from the post-processing of raw PIV images showed higher momentum flux injection in the swirl distributed flow zone case as compared to the normal swirl flow case. Enhanced velocity fluctuations were also observed in both the axial and radial direction for the distributed swirl flow case resulting in higher turbulence for the examined condition. The distributed swirl flow case showed a prominent corner recirculation zone along with higher flow entrainment within the recirculation zone. Enhanced interaction of average streamlines with vortices was found in the swirl distributed flow case. Increased turbulent fluctuation in the two different spatial directions was responsible for higher Reynolds stress distribution (u′v′) in the distributed flow case, indicating improved mixing behavior at lower global oxygen concentrations from the carbon dioxide (CO2) dilution, and showed different length scales of turbulent eddies. Furthermore, the spatial local Damkӧhler number values for distributed flow case (for its implication in reacting case) were found to be less than unity. The results showed a shorter flow timescale than the corresponding chemical timescales in distributed reaction zone. These results help support substantiating the difference of reaction regimes on the Borghi diagram (plot of velocity fluctuation/ laminar flame speed versus the integral length scale/ flame thickness) between the distributed reaction zone (that possesses thickened reaction zone) and conventional swirl reaction flow regimes having corrugated flamelet zone.

The value of using heterogeneous detector groups for the development of time-of-flight (TOF) positron emission tomography (PET) systems.

Objective. Much recent attention on positron emission tomography (PET) is the development of time-of-flight (TOF) systems with ever-improving coincidence time resolution (CTR). This is because, when all other factors remain the same, a better CTR leads to images of better statistics and effectively increases the sensitivity of the system. However, detector designs that aggressively improve the CTR often compromise the detection efficiency (DE) and offset the benefit gained. Under this circumstance, in developing a TOF PET system it may be beneficial to employ heterogeneous detector groups to balance the overall CTR and DE of the system. In this study, we examine the potential value of this system design strategy by considering two-dimensional systems that assume several representative ways of mixing two detector groups.Approach. The study is based on computer simulation and specifically considers medium time-resolution (MTR) detectors that have a 528 ps CTR and high time-resolution (HTR) detectors that have a 100 ps CTR and a DE that is 0.7 times that of the MTR detector. We examine contrast recovery, noise, and subjective quality of the resulting images under various ways of mixing the MTR and HTR detectors.Main results. With respect to the traditional configuration that adopts only the HTR detectors, symmetric heterogeneous configurations may offer comparable or better images while using considerably fewer HTRs. On the other hand, asymmetric heterogeneous configurations may allow the use of only a few HTRs for improving image quality locally.Significance. This study demonstrates the value of the proposed system-level design strategy of using heterogeneous detector groups for achieving high effective system sensitivity by factoring into the tradeoff between the CTR and DE of the detector.

An Advanced Control Performance of a Sophisticated Stand-Alone Wind-Driven DFIG System

To supply resident loads far from the grid, a stand-alone wind system with a small-scale wind turbine and battery storage can be used. The traditional configuration of the system has a permanent-magnet synchronous generator (PMSG). Other alternative configurations use doubly fed induction generator (DFIG). The systems with DFIG have variable speed operation with a limited speed range which reduces the captured power from the wind turbine. Also, there is a rotor-side converter (RSC) which carries the reactive power of DFIG, in addition to the slip power. In this paper, an improved system configuration with DFIG is controlled by an advanced control scheme. By this advanced scheme, the speed range is increased such that maximum power operation of wind turbine is obtained for complete range of wind speed, and volt-ampere (VA) requirements of RSC are reduced by the operation at nearly zero-slip power.

Design and Selection of Inductor Current Feedback for the Sliding-Mode Controlled Hybrid Boost Converter

The hybrid step-up converter is a fifth-order system with a dc gain greater than the traditional second-order step-up configuration. Considering their high order, several state variables are accessible for feedback purposes in the control of such systems. Therefore, choosing the best state variables is essential since they influence the system’s dynamic response and stability. This work proposes a methodical method to identify the appropriate state variables in implementing a sliding-mode (SM) controlled hybrid boost converter. A thorough comparison of two SM controllers based on various feedback currents is conducted. The frequency response technique is used to demonstrate how the SM method employing the current through the output inductor leads to an unstable response. The right-half s-plane poles and zeroes in the converter’s inner-loop transfer function, which precisely cancel one another, are what is causing the instability. On the other hand, a stable system may result from employing a SM controller with the current through the input inductor. Lastly, some experimental outcomes using the preferred SM control method are provided.