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Computer modeling and simulation (CM&S) technology is widely used in the medical device industry due to its advantages such as reducing testing time and costs. However, the developer's parameter settings during the modeling and simulation process can have a significant impact on the results. This study developed a test model for the rotational shear strength of dental implants and the constraint force of total knee replacements based on CM&S technology and proposes ideal parameters to ensure reliability. For dental implants, the load area and sliding contact conditions were considered, and for total knee replacements, the friction coefficient, medial–lateral displacement, valgus–varus rotation, and elastic modulus were considered. By comparing the simulation results and mechanical tests, boundary conditions with an error rate of less than 1.5% were selected. When a jig (gripper and collector) was applied with the same boundary conditions, an error rate of 48~22% occurred; otherwise, it was confirmed that the error rate was within 10~0.2%. The FE model was verified with an error of 2.49 to 3% compared to the mechanical test. The friction coefficient variable had the greatest influence on the results, accounting for 10 to 13%, and it was confirmed that valgus–varus rotation had a greater influence on the results than medial–lateral displacement. Relatively, the elastic modulus of the insert had the least effect on the results. These research results are expected to make CM&S techniques useful as a medical device digital development tool (M3DT) in the development of total knee replacements and dental implants. [ABSTRACT FROM AUTHOR]

This paper presents the direct compensation of the switching interval error of the effective voltage vectors by the dead time of a pulsewidth modulation voltage source inverter (PWM-VSI). The output voltages of a three-phase PWM-VSI are distorted and have voltage errors from the dead time to avoid the shoot-through of inverter arms and the time delay of the gate drive. Voltage distortion increases the harmonics of the output voltages and decreases control performance. This paper presents a simple and direct compensation technique to solve this problem in a three-phase VSI. The practical switching output voltages are determined by the dc-link voltage, the switching signals of each phase, the dead time, the time delay, and the current polarities of each phase. For these reasons, output voltage errors are not constant. In order to analyze the dead-time effect in the actual switching voltages of each phase, the practical switching voltages in a sampling period of a space vector PWM (SVPWM) method are calculated according to the current polarity. In the calculation, the dead time, the time delay of devices, and the voltage drops on power devices are included to consider nonlinear voltage distortion. From these practical switching voltages during the switching intervals in a sampling period, the average output voltages of each phase can be derived, and the output voltage errors between the voltage commands and the average output voltages of each phase are obtained. The SVPWM switching intervals of each phase can be derived by the average output voltages that are calculated according to the current polarity and nonlinear voltage distortion to compensate for the output voltage errors. With the simple detection of the current polarity, the practical errors of the switching intervals of each phase can be compensated by the addition of the compensated switching time. Simulation and experimental results validating the proposed compensation method are presented in this paper. [ABSTRACT FROM AUTHOR]

This study presents the design of a 2‐pole high‐speed BLDC motor for kitchen blenders and its control method with the aim to reduce the speed ripple that decreases the grinding performance in the high‐speed region. In blender machines, the high pulsating load caused by the blending materials such as ice cubes acting on the grinding blade, create significant speed ripple in the constant power region. Because current and torque are limited to protect the drive, the actual motor torque cannot overcome the pulsated load if the speed reference is maintained. Therefore, the speed fluctuates, and the grinding performance is lowered. In the proposed variable speed reference control scheme, the speed command is continuously modified to overcome the maximum pulsating torque requirement which results in lower speed ripple. To achieve this, if the load torque suddenly increases, the current value is then set based on the maximum load and speed reference value is temporarily lowered. If then the load torque becomes lower than the actual torque, the previously set speed reference value is reused. The design result and grinding performance of the proposed control method are verified by simulations and experiments. Hard white beans are used for actual performance testing. [ABSTRACT FROM AUTHOR]

Electric motors with a double air-gap structure offer increased power or torque density compared to their single air-gap counterparts, achievable through double-stator or double-rotor configurations. In a previous study, the authors proposed a double-stator permanent magnet synchronous motor (PMSM) with a magnetic screen placed in the middle of the rotor to isolate the outer and inner motors. However, the analysis of the magnetic screen was not provided in that study, as the design was arbitrarily chosen. This research focuses on the effects of the magnetic screen size and selects the appropriate dimensions for optimal motor performance. Finite element analysis (FEA) is employed to assess the electromagnetic characteristics of the screen. Subsequently, the motor is manufactured and tested. The results show that the chosen magnetic screen size contributes to significant efficiency improvements. In particular, the motor achieved an efficiency of 95.2% during the qualification test, surpassing the efficiency obtained in the previous study. [ABSTRACT FROM AUTHOR]

A new combined boost-Cuk-forward (CBCF) converter with ripple-free input current and low switch voltage stress is proposed for high step-up applications. Two coupled inductors are applied to achieve low switch voltage stress as well as balanced dc-link voltages, wherein the former is placed in series with the boost diode, and the latter is formed as a forward converter. Because these inductors are coupled with the output Cuk inductor, a ripple-free input current is also attained. The proposed converter is run at discontinuous conduction mode (DCM) by applying a low output-side Cuk inductance to reduce the switching loss by providing a ZCS turn-on of MOSFET and removing the diode reverse recovery current. In addition, the proposed converter does not have a problem with ground leakage current. The practical results verify the performance and effectiveness of the proposed CBCF high step-up converter. [ABSTRACT FROM AUTHOR]

This paper focuses on a minimal current sensing strategy and fault detection of switched reluctance machines (SRMs). In order to reduce the number of required current sensors in multiphase motor drives, the optimal selection and location of current sensors is presented in consideration of the precise actual phase current measurement, open- and short-circuit fault detection. The proposed scheme requires two current sensors to replace the phase current sensors placed in each phase without any additional devices for multiphase SRMs to achieve a more compact and low-cost drive. Different current regulation methods are employed for single phase conducting region and commutation region. To obtain the phase currents from the proposed approach, different settings of the pulsewidth modulation signals for adjacent phases during the commutation region are implemented. The simulation and experiments on a four-phase 8/6 pole SRM are carried out to verify the effectiveness of this approach in the healthy and faulty cases. [ABSTRACT FROM AUTHOR]

In the present study, a NiS@ZnS composite nanostructure was synthesized on a nickel foam substrate by a facile chemical bath deposition (CBD) method. The prepared composites were analyzed by X-ray photoelectron spectroscopy, high resolution transmission electron microscopy, and field emission scanning electron microscopy. The electrochemical performance of the supercapacitor (SC) electrodes was examined by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The NiS@ZnS composite exhibited a cabbage leaf like nanostructure and showed outstanding electrochemical performance in SCs with a specific capacitance of 1533.0 F g−1 at a current density of 7.5 A g−1, good cycling stability with 97.9% retention over 3000 cycles, greater energy density, and excellent rate capability compared to the bare NiS (1279.83 F g−1) and ZnS (616.66 F g−1)-based electrodes in SCs. The facile, novel synthesis method, outstanding performance, well defined surface morphology, synergetic effect and low cost make the NiS@ZnS composite an ideal electrode material for electrochemical energy storage devices. [ABSTRACT FROM AUTHOR]

In this work, a hybrid method based on the lattice Boltzmann method (LBM) combined with smoothed profile method (SPM) is proposed for simulating the fluid flow and heat transfer in particulate systems. LBM is used to evaluate the flow field, while the temperature distribution is computed by a finite difference method. The no-slip and constant temperature boundary conditions on particle surfaces are treated with SPM. The following benchmarking studies are considered to validate the accuracy and robustness of the proposed method: natural convection in a square cavity with a heated circular cylinder, natural convection in a concentric annulus, and the sedimentation of single and two circular particles in a long narrow container. In all the studies, the results obtained from the present technique based on hybrid method show good agreement with the previously published results and those given by LBM combined with SPM based on the double-population model. After evaluating the central processing unit time taken by the two methods, it was found that the proposed method is about 50% more computationally efficient than the method based on double-population model in all the simulation cases considered in this work. [ABSTRACT FROM AUTHOR]

MnNi2O4–PbS composites have been successfully deposited on a nickel (Ni) foam substrate using a simple and cost-effective two-step hydrothermal route for application as supercapacitor electrode materials in energy storage devices. The morphological, structural and physical behaviors of the as-prepared composite were evaluated, and the results indicate that the PbS nanoparticles were successfully anchored onto the surface of MnNi2O4 nanoflakes. The electrochemical studies reveal that the MnNi2O4–PbS composite exhibits a higher supercapacitor performance with a high specific capacitance of 1176.76 F g−1 at 1 A g−1 and improved cycling stability with 98.86% retention after 4000 cycles, which are much higher than that of the MnNi2O4 electrode. The improved electrochemical performance of the composite electrode is mainly due to its unique hierarchical structure, which provides a better contact of the electrolyte and electrode surface, and a large number of active sites. These results suggest that the unique MnNi2O4–PbS electrode would be a promising electrode for high-performance supercapacitor applications. [ABSTRACT FROM AUTHOR]

Nanoparticle-featured MoS2 and WS2 have been synthesized using a facile one-step hydrothermal approach and their application as electroactive materials for high-performance supercapacitors has been investigated. The electrochemical results of the MoS2 electrode exhibit a higher specific capacitance (Cs) of 1531.2 F g−1 at 5 mA cm−2 with good cycling stability (up to 81.6% retention over 3000 cycles). The WS2 electrode delivers a high Cs of 1439.5 F g−1 at 5 mA cm−2 and excellent cycling stability with 77.4% retention after 3000 cycles. The outstanding performance of the MoS2 and WS2 electrodes indicates their potential in next-generation high-performance supercapacitor applications. [ABSTRACT FROM AUTHOR]

The switched reluctance motor (SRM) benefits from its magnet-free nature, robust construction, low cost, flexible controls, and the ability to operate in harsh environments such as high temperatures and high pressure. It has received increasing attention for all-electric or multi-electric aircraft systems and electric vehicles (EVs) as compared with permanent magnet synchronous motors (PMSM) and other AC motors in some required high reliability and fault tolerance applications. However, the SRM is prone to considerable wind resistance due to the convex pole structure of the rotor during high-speed rotation, high torque ripple, and also vibration noise. Thus, it is currently a trending topic to develop special SRMs, tailored with high reliability and fault tolerance. Recent research demonstrates several promising feasible solutions to reduce torque ripples and enhance torque density and power factors, including changing topology of SRM, using advanced control methods, as well as different winding configurations. Among these options, the segmented switched reluctance motor (SSRM), as a deformation of the conventional topology, is shown to be capable of effectively optimizing the torque performance. Motivated by this advance, this paper aims to present a comprehensive literature review on the SSRM, first illustrating the development of the topology of the SRM, then providing a description as well as a classification according to the topology of the SSRM. In particular, we focus on the evolution of various kinds of segmental topology and improvement measures. Then, we discuss the performance, advantages, and disadvantages of various types of structures in terms of their electromagnetic aspects and their applications. Eventually, several promising future trends and application prospects of the SSRM are prospected, with the aim of shedding light on further research. In sum, the key contribution of this paper is to provide a valuable basis for detailed analyses of the structure and electromagnetic design of the SSRM that are expected to benefit future research. [ABSTRACT FROM AUTHOR]

With the rapid development of power electronic techniques and the increasing cost of permanent magnets (PMs) materials, switched reluctance motors (SRMs) have recently gained more attention. However, traditional SRMs have a relatively low torque density. For the sake of increasing the motor torque density, this paper proposes a novel segmental rotor type SRM. The proposed motor adopts hybrid stator poles and concentrated windings in the stator side and a segmental rotor structure in the rotor side, which is completely different from the structures of the traditional SRM. The special structure of the motor shortens the magnetic flux paths of the motor, separates the parts of the magnetic flux paths from one another, and eradicates the magnetic flux reversal in the motor stator in order to improve the electric utilization and output torque density of the motor. Meanwhile, the requirement of the magneto-motive force and the core loss of the motor is also decreased, thereby improving the efficiency of the motor. For the purpose of proving the proposed structure, the characteristics of the motor are analyzed using the finite element method and are compared to those of the traditional 12/8 SRM, which is designed for the same application. Moreover, the prototypes of the traditional 12/8 and proposed SRMs are manufactured, and experiments based on the prototypes are performed. Finally, the effectiveness of the structure of the proposed motor is further proven by the experimental results. [ABSTRACT FROM AUTHOR]

This paper presents a novel 6/5 segmental rotor-type switched reluctance motor (SRM) for cooling fan application. Unlike conventional structures, the rotor of the proposed structure is constructed from a series of discrete segments, and the stator is constructed from two types of stator poles: exciting and auxiliary poles. Meanwhile, the windings are only placed around the exciting poles, resulting in short flux paths and no flux reversal in the stator of the proposed SRM. Hence, the proposed structure may increase the electrical utilization and reduce magnetomotive force (MMF) requirement compared to conventional SRMs. To verify the proposed structure, the operation principle and the design rules of the proposed structure are illustrated and expounded. The finite-element method (FEM) is employed to get the static and dynamic characteristics of the conventional 12/8 and proposed SRMs. Furthermore, the prototype is manufactured and tested. Finally, the simulation and experimental results are presented and analyzed to verify the effectiveness of the proposed SRM. [ABSTRACT FROM AUTHOR]

In this paper, three types of bearingless switched reluctance motors (BLSRMs) which have decoupled flux characteristics between the torque and suspending current are presented in detail. The analyzed BLSRMs are an 8/10 hybrid BLSRM, a 12/14 hybrid BLSRM, and a double stator BLSRM. The 8/10 hybrid BLSRM has a low electrical frequency with decoupling characteristics. The 12/14 hybrid BLSRM has a short flux path to reduce core loss with higher decoupling characteristics. The double stator BLSRM has the best decoupling characteristics with a complex mechanical structure. All three structures have two types of stator poles: torque and suspending force poles. Due to the independent characteristics between the torque and suspending force poles, the torque control can be decoupled from the suspending force control. The characteristics of the three types, such as magnetic flux distribution, inductance, torque, suspending force, torque ripple, efficiency, and number of switches used in the drive systems, are analyzed and compared to induce the better magnetic structure and control scheme of the suspending force. To verify the validity of the three types, tests are executed and compared. [ABSTRACT FROM AUTHOR]

Background: We aimed to improve the tumor localization system using radiofrequency identification (RFID) technology used during laparoscopic surgery for gastric and colorectal cancer. To this end, we developed a detection algorithm and designed improvement for the RFID clip. Methods: To evaluate the proposed system, a swine-based animal study was conducted, followed by experiments on porcine stomachs and colons using the EASIE-R simulator. The success rates of endoscopic clipping, detection time, and detection accuracy, which is the distance between the detection point and RFID tag, were measured. Results: Results of the in vivo swine animal study showed success in all three clippings and detections of the RFID clips. Results of the 60 RFID endoclip attempts using the EASIE-R simulator showed a total clipping success rate of 85.0% (n = 51/60; stomach, 83.3%, n = 25/30; colon, 86.7%, n = 26/30). The median detection times were 29.2 s for the stomach and 25.5 s for the colon. The median detection accuracy was 4.0 mm for the stomach and 4.5 mm for the colon. Conclusions: We confirmed that the proposed RFID-based system showed improvements over the system of a previous study. This RFID-based system is effective at localizing gastric and colorectal tumors. [ABSTRACT FROM AUTHOR]

The shift-by-wire (SBW) system in vehicles aims to increase performance, safety, and comfort during driving. Switched reluctance motors (SRMs) are simple, resilient, and require only minimum maintenance; these factors make it a good option for use as an SBW actuator. Inherently, SRM generates a higher torque ripple than other AC machines, which can lead to a deterioration of its function. In this paper, a non-uniform air-gap rotor structure combined with the careful positioning of holes near the pole surface is proposed to reduce the torque ripple. The finite element method (FEM) is employed to analyze the electromagnetic characteristics of the design. The proposed motor is manufactured, and experiments are done to verify the performance. The design alone can reduce the torque ripple by 7% and flatten the torque waveform. The experimental result shows that the proposed motor can achieve the desired performance. The estimated torque ripple from the experiment is 26.65%. [ABSTRACT FROM AUTHOR]

This paper proposes a novel 12/8 switched reluctance motor (SRM) with segmental rotor for vehicle cooling fan application. Unlike conventional SRMs, the proposed motor adopts one body stator with hybrid stator poles and segmental rotor structures, thereby making the motor operate in short flux paths and parts of the flux paths magnetically isolated between the phases. Therefore, compared with conventional SRMs, the proposed structure not only improves the output torque density and reduces the magneto-motive force requirement and core losses of the motor, but also inherits the advantages of conventional SRMs like flexible control as well as the adaptability in harsh environment. To verify the proposed structure, a finite element method is employed to get characteristics of the proposed SRM. Meanwhile, a conventional 12/8 SRM, which has been used for vehicle cooling fan application, is also analyzed for comparison. Furthermore, the prototypes for the conventional and proposed 12/8 SRMs are manufactured and tested. Finally, the simulation and experimental results are presented and analyzed to verify the effectiveness of the proposed SRM. [ABSTRACT FROM AUTHOR]

A cost-effective and uniform crystal with different structures was fabricated using a facile chemical bath deposition technique for electrochemical supercapacitor (SC) applications. In this study, CuS, PbS, and CuS@PbS composite electrodes were fabricated for SCs. The morphology and structure of the electrodes were analyzed by field emission–scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The CuS@PbS composite electrode delivered outstanding electrochemical performance in SCs with a high specific capacitance of 1004.42 F g−1 at a current density of 2.85 A g−1, good cycling stability (only 2.9% loss after 3000 cycles at 2.85 A g−1), higher energy density of 33.89 Wh kg−1 at a power density of 714.28 W kg−1, and an excellent rate capability compared to other electrodes. These results show that the CuS@PbS composite can be used to improve the surface morphology and is a promising positive electrode material for SC applications. [ABSTRACT FROM AUTHOR]

Based on the back electromotive force (back‐EMF) detection, a novel rotor position estimation strategy with adjustable turn on/off angle is proposed for the high‐speed hybrid switched reluctance motor (SRM). The minimum back‐EMF position is captured in every electrical cycle for rotor position estimation. The current comparator is employed to send out a turn‐off signal for phase winding when the maximum inductance position is detected in the first electrical cycle. By providing sufficient current rise time to the phase winding, the proposed sensorless control system enables the motor to run in high‐speed application. Besides the straightforward estimation principle, the proposed strategy has the implemental feasibility by eliminating extensive calculations and complicated look‐up tables. The experimental results of a prototype are demonstrated to verify the proposed sensorless control system. [ABSTRACT FROM AUTHOR]

Selection of electrical machine is a key issue in electrical and hybrid electrical vehicles (HEVs and EVs). As far as HEVs and EVs are concerned, mechanical ruggedness of electrical machine is of utmost importance. For these reasons, the application of switched reluctance (SR) machine in EVs and HEVs is a viable option. In this study, an SR generator (SRG) has been utilised to work as a battery charger in EVs. The current ripple of the SRG is the greatest issue when it works as a battery charger. Therefore, a power converter and a smart search control (SSC) approach are proposed in this study to decrease the current ripple when the output power has a maximum quantity. During the system operation, the SSC method determines the value of excitation angle, turn‐on and turn‐off angles for each phase of SRG. The simulation and experimental results demonstrate the eligibility of the SSC system and power converter to obtain the acceptable charging current in maximum generated power during battery charging. [ABSTRACT FROM AUTHOR]

This paper presents a sensorless-controlled, low-cost, low-power, and variable-speed drive system suitable for fan and pump applications. The main advantages of this drive system are the low system cost, simple converter structure, and simple but robust sensorless control technique. The drive motor is a special hybrid switched reluctance motor. The proposed sensorless control method beneficially utilizes the stator side PM field and its performance is motor parameter independent. The unique low-cost drive system solution, simple and robust sensorless control features of this drive system, is demonstrated in detail in this paper. Important design details for practical implementation of the sensorless control algorithm are included. The complete drive system performance is validated using a prototype drive system. [ABSTRACT FROM AUTHOR]

Nanocomposite electrodes receive much attention because of their excellent energy storage nature. Electrodes for supercapacitors have come a major source of interest. In this pursuit, the current work elucidates binder-free coral reefs resembling ZnO/CoS2 nanoarchitectures synthesized on the surface of Ni foams employing the cost-effective hydrothermal route. The Zno/CoS2 nanocomposite demonstrated excellent battery-type behavior, which can be employed for supercapcitor application. Various analyses were carried out in the current study, such as X-ray diffraction and high-resolution scanning electron microscopy, which allowed defining the crystalline nature and morphology of surface with ZnO/CoS2 nanoarchitectures. Electrochemical measures such as cyclic voltammetry, galvanostatic charge discharge, and potentiostatic impedance spectroscopy confirmed the battery-type behavior of the material. The synthesized precursors of binder-free ZnO/CoS2 nanostructures depicted an excellent specific capacity of 400.25 C·g−1 at 1 A·g−1, with a predominant cycling capacity of 88. 2% and retention holding of 68% at 10 A·g−1 and 2 A·g−1, even after 4000 cycles, representing an improvement compared to the pristine ZnO and CoS2 electroactive materials. Therefore, the electrochemical and morphological analyses suggest the excellent behavior of the ZnO/CoS2 nanoarchitectures, making them promising for supercapacitors. [ABSTRACT FROM AUTHOR]

In this paper, the optimization and characteristics analysis of a three-phase 12/8 switched reluctance motor (SRM) based on a Grey Wolf Optimizer (GWO) for electric vehicles (EVs) application is presented. This research aims to enhance the output torque density of the proposed SRM. Finite element method (FEM) was used to analyze the characteristics and optimization process of the proposed motor. The proposed metaheuristic GWO combines numerous objective functions and design constraints with different weight factors. Maximum flux density, current density, and motor volume are selected as the optimization constraints, which play a significant role in the optimization process. GWO performs optimization for each iteration and sends it to FEM software to analyze the performance before starting another iteration until the optimized value is found. Simulations are employed to understand the characteristics of the proposed motor. Finally, the optimized prototype motor is manufactured and performance is verified by experiment. It is shown that the torque can be increased by 120% for the same outer volume, by using the proposed method. [ABSTRACT FROM AUTHOR]

Permanent magnet Vernier machine (PMVM) is a strong candidate for direct-drive applications in low-speed region because its power characteristic is higher than conventional permanent magnet machine (PMM). In this paper, the design of a dual-stator PMVM (DSPMVM) with spoke-type rotor is introduced. As a radial motor with dual-stator configuration, one on the outer and inner side, the rotor is equipped with support bars for practical and simple manufacturing, which is the aim of this study. The characteristics and performance of the proposed machine with and without the support bar are examined with finite element analysis (FEA). The DSPMVM and the support were manufactured and tested through experiments to verify proposed structure. Both simulation and experiment results show that there is little to no difference in performance when the support bar is equipped. Furthermore, the average deviation between simulation and experiment results is approximately 7% which is within the acceptable range. [ABSTRACT FROM AUTHOR]