Parameter Design Research Articles

The synergistic effect of vertical structural parameters of vertical-type two-dimensional hole gas diamond MOSFETs on improving the overall performance of devices based on TCAD simulation

Vertical-type two-dimensional hole gas (2DHG) diamond metal-oxide-semiconductor field effect transistors (MOSFETs), featuring vertical geometry and typically p-channel, are poised for application in future logic technology, high-voltage and high-power miniaturization complementary circuits. P-channel achieving high breakdown voltage and low on-resistance can be realized through the use of p− drift layer, while a trench structure is shown to be beneficial for increasing the drain current density of vertical-type devices. However, the cumulative impact of these key parameters on the performance of vertical-type diamond MOSFETs remains unclear. In this paper, we explore the physical mechanism that how the key parameters design affects on off-state, breakdown and output characteristics has been simulated using Silvaco TCAD tools. We propose a vertical-type trench-gate 2DHG diamond MOSFET that is favorable for general integration applications and exhibits equivalent performance to the double-gate vertical structure without relying on a high concentration of nitrogen doped layer. This demonstrates that our work offers a universal approach for optimizing the comprehensive device performance in vertical-type structures, accounting for the effects of multiple parameters across all wide bandgap material-based FETs.

Response Surface Optimization Design of G20CrMo Composite Surface Cylinder Texture Parameters and Analysis of Tribological Performance

Response Surface Optimization Design of G20CrMo Composite Surface Cylinder Texture Parameters and Analysis of Tribological Performance

Parameter Design of Sand Casting to Minimize Shrinkage Defects, Porosity Defects and Incomplete Defects

Casting is one of the most commonly used manufacturing method for geometrically complex product. Among the casting technologies, sand casting is often found in application. Beside the advantages of the sand-casting process, it also has a drawback that is often encountered, namely product defects. Product defects can be caused by a lack of attention to sand casting parameters. This work aims to minimize those defects, including porosity defects, shrinkage defects and incomplete defects by optimizing process parameters using the Taguchi method. The identified sand-casting process parameters include gating location, riser location, molding conditions and pouring temperature with each parameter consisting of 3 levels. This research using the fractional factorial L9 (34). Data processing is carried out by analysis of mean (ANOM) to obtain plot effects. The results showed that the optimal combination of parameters that resulted in shrinkage, porosity and minimal incomplete defects were at gating location level 2, riser location level 1, mold condition level 2 and pouring temperature level 3. The results of the comparison before and after optimization were an increase of 0.77, where previously it was 1.30 to 2.07 based on normalized data.

Optimization design of heliostat field parameters based on gray Wolf algorithm

Optimization design of heliostat field parameters based on gray Wolf algorithm

New energy vehicle technology research - Charging technology

In recent years, Chinas economic development is becoming more and more rapid, leading to the increasingly serious pollution emission problem of traditional fuel vehicles. In order to solve the environmental problems, the transformation of automobiles has become an urgent problem. At the present stage, electric vehicles are also widely concerned by all sectors of society because of their low carbon emissions, energy saving and low use cost. With the rapid growth of electric vehicle sales, the demand for charging piles is rising, and the mainstream charging facilities for new energy vehicles are still in short supply. Therefore, we need to focus on efficient wireless charging to solve the major problems in the current electric vehicle industry. This paper analyzes the wireless dynamic energy transmission technology, extending the service life of the battery, how to reduce the cost, the optimization of coil parameters design, the offset of transmission coil and receiving coil, foreign body detection and overheating problems.

Understanding the impact of persistence and propagation on the Age of Information of broadcast traffic in 5G NR-V2X sidelink communications

The current Cellular V2X (C-V2X) standard for direct communication between vehicles is based on the so called Semi-Persistent Scheduling (SPS) algorithm. It is based on the multiple access structure of 5G New Radio (NR) and exploits sensing and persistence to realize a randomized multiple access. We consider the application of SPS to support periodic broadcast traffic where no acknowledgments are provided. Persistence is a key feature, which consists of a node using the same resource for its transmissions for multiple frames. The specific resource used is randomly selected from among those that are perceived to be idle, and reselected anew after a randomized number of frames. We define a model to gain insight into the interplay between persistence and key performance metrics for the type of traffic considered, namely probability of successful delivery and Age of Information (AoI). A core version of the model is validated against simulations and used to show that there exists an optimal level that minimizes AoI. The model is then extended to account for a distance-dependent propagation model, allowing further insight into the effects of the interplay between sender–receiver distance and persistence. Finally, an even more detailed model is investigated, using ns-3-based simulations. This further analysis confirms the qualitative behaviors revealed by the analytical model and provides more insight into the complex interactions of system parameters and channel characteristics. The obtained results help to identify the limits of SPS, opening the way to system-principled parameter optimization and design of more powerful variants of the multiple access scheme.

Active Equalization of Lithium Battery Pack with Adaptive Control based on DC Energy Conversion Circuit

Background:: How to solve the inconsistency of battery pack is a key point to ensure reliable operation of electric vehicles. Battery equalization is an effective measure to address the inconsistency. Passive equalization method has poor efficiency and thermal management problems. Average voltage equalization method is only suitable for situations where there is a significant voltage difference between batteries. The SOC-based equalization method is relatively difficult and may inevitably lead to the accumulation of errors during the process. Objective:: In order to avoid the disadvantages of traditional control methods, a new control method is proposed to improve the accuracy and self-adaptation of active equalization, which is easy to be realized without online calculation. Methods:: Cascaded bidirectional Buck-boost circuit is adopted as the novel equalization topology. Based on fuzzy PID theory, an adaptive digital-analog hybrid control strategy based on fuzzy PID is proposed in this paper. Parameter design of the fuzzy PID controller is carried out. A battery equalization system based on cascaded bidirectional Buck-boost circuit is designed and developed. Experimental verification is conducted on relevant hardware platforms. Results:: An adaptive digital-analog hybrid control strategy based on fuzzy PID is proposed. Compared to passive equalization, this proposed method provides high efficiency. Regarding traditional voltage control, the method improves control reliability and flexibility. Compared to the average voltage equalization method, the approach needs less convergence time. Moreover, the control method is much easier to realize than the SOC-based equalization method. Conclusion:: By using the presented adaptive control based on DC energy conversion circuit, the degree of self-adaptation of the equalization process has been obtained as higher and the inconsistency as smaller.

Composite effects of residual stress and hardness gradient on contact fatigue performance of rough tooth surfaces and optimization design of detailed characteristic parameters

Residual stress and hardness gradient significantly affect the contact fatigue failure process of rough tooth surfaces, and the meticulous design of their characteristic parameters can help improve the fatigue resistance of gears. In this paper, an efficient computational method for rough tooth surface contact is established based on the reconstruction modeling of asperities and mixed lubrication analysis. By comprehensively considering the effects of residual stress and hardness gradient, the Dangvan multiaxial fatigue criterion is adopted to predict and analyze the contact fatigue life of the gear surface. The correlation between the surface residual stress, maximum residual stress depth, surface hardness, and effective hardening layer depth, among other characteristic parameters, and the contact fatigue performance of tooth surfaces is established. The results show that: (1) Increasing the magnitude of surface residual compressive stress and surface hardness can significantly reduce the risk of fatigue failure in the near-surface layer of the gear. To achieve the same fatigue performance, there is a linear negative correlation between the design values of the two parameters. (2) Affected by the double stress peaks in the rough tooth surface stress field, the maximum residual stress depth significantly affects the depth at which the highest failure risk occurs. With changes in roughness, the optimal design value of the maximum residual compressive stress depth changes from about 0.5 times the Hertzian contact half-width depth in the subsurface layer (Sa < 0.2 μm) to about 15 μm in the near-surface layer (Sa > 0.4 μm). (3) Considering both process cost and gear surface fatigue resistance, the design threshold for the effective hardening layer depth should be greater than the Hertzian contact half-width. This paper establishes a composite correlation between the meticulous characteristic parameters of residual stress, hardness gradient, and the contact fatigue performance of tooth surfaces, providing theoretical support for optimal design of tooth surface anti-fatigue performance.

Influence Analysis of Voltage Imbalance in Input-Series, Output-Parallel (ISOP) Multichannel IPT System

In order to solve the demand for efficient and stable low-voltage, high-power energy transmission capacity of electric vehicle (EV) fast charging, an ISOP-IPT system based on inductor-capacitor-capacitor series (LCC-S) compensation network is proposed. Firstly, the influence of compensation parameter inconsistency on the system is analyzed. On this basis, considering the resistance of coupler coils, the overall transmission efficiency of the system is analyzed. It is found that the voltage imbalance of the system will affect the working state of inverters, and then affect the stability of the system. The system transmission efficiency increases with the increase in mutual inductance. Moreover, the voltage imbalance caused by the inconsistency of compensation parameters and mutual inductance will reduce the transmission efficiency of the system. Finally, it is concluded that in the parameter design of the ISOP-IPT system, mutual inductance should be improved on the basis of ensuring the input voltage equalization of each channel so as to improve the transmission efficiency and working stability of the system. The experimental platform of a two-channel ISOP-IPT system is built and the maximum efficiency is 94.03%, which verifies the correctness of theoretical analysis.

Influences of clean fracturing fluid viscosity and horizontal in-situ stress difference on hydraulic fracture propagation and morphology in coal seam

The viscosity of fracturing fluid and in-situ stress difference are the two important factors that affect the hydraulic fracturing pressure and propagation morphology. In this study, raw coal was used to prepare coal samples for experiments, and clean fracturing fluid samples were prepared using CTAB surfactant. A series of hydraulic fracturing tests were conducted with an in-house developed triaxial hydraulic fracturing simulator and the fracturing process was monitored with an acoustic emission instrument to analyze the influences of fracturing fluid viscosity and horizontal in-situ stress difference on coal fracture propagation. The results show that the number of branched fractures decreased, the fracture pattern became simpler, the fractures width increased obviously, and the distribution of AE event points was concentrated with the increase of the fracturing fluid viscosity or the horizontal in-situ stress difference. The acoustic emission energy decreases with the increase of fracturing fluid viscosity and increases with the increase of horizontal in situ stress difference. The low viscosity clean fracturing fluid has strong elasticity and is easy to be compressed into the tip of fractures, resulting in complex fractures. The high viscosity clean fracturing fluids are the opposite. Our experimental results provide a reference and scientific basis for the design and optimization of field hydraulic fracturing parameters.

Effect of surface topography and roughness on the leakage of static seals

Static seal is widely used in modern machinery. Leakage of static seals would shorten the mechanical system’s service life and affect the environment. To understand the leakage characteristics of static seals, in this work, an experimental apparatus for leakage quantization was built. The effects of surface topography and roughness on the leakage performance of static seals subject to elevated pressure were highlighted. It was found that the leakage rate is negatively correlated with contact pressure. Orientation of surface topography affects the leakage, where the grinding scar parallel to the leakage direction contributes to the leakage, and the perpendicular grinding scar has an inhibiting effect. The leakage rate of irregular and discontinuous surface topography is lower than that of regular ones, and it increases with increasing surface roughness. Furthermore, the leakage mechanism of surface topography and roughness was revealed. This work provides general guidance for the parameters design of static seals.

Design and development of an LC compensated WPT system with multiple constant voltage outputs function

SummaryWith the increasing demand for the constant voltage (CV) charging of multiple loads, this article proposes an LC compensated wireless power transfer (WPT) system with multiple load‐independent CV outputs function. Each transmission channel consists of a compensation capacitor and a compensation inductor forming a resonant loop. By configuring different combinations of compensation inductor and capacitor for each transmission channel, different CV outputs can be achieved without affecting the output voltages of other transmission channels. In addition, the proposed system can achieve near zero phase angle (ZPA) and zero‐voltage switching (ZVS) operations, thereby improving system efficiency. Firstly, a detailed theoretical derivation of the proposed system with multiple load‐independent CV outputs and ZPA operation is performed, and the detailed parameter design process is provided. Secondly, the implementation method of ZVS operation is introduced and verified through simulation. Finally, an experimental prototype of two transmission channels is taken as an example to verify the correctness and rationality of the proposed system.

Continuous production machine for separating and shaping Taiping Houkui tea.

In response to the challenges of low automation and a lack of a continuous processing system for Taiping Houkui tea, this study proposed a design scheme for a continuous processing line and built a continuous processing prototype for testing by combining the production requirements of Taiping Houkui tea, the characteristics of withered leaves, and the existing relevant production equipment. First, the physical properties of Taiping Houkui tea were determined. A simulation was performed using the Hertz-Mindlin model, and the motion states of the tea leaves were obtained under different conditions to define the parameter design range of the experimental platform and verify its structural rationality. Then, the response surface methodology was used to optimize the working parameter ranges and obtain the best working parameters for the feeding and kneading mechanisms. Finally, a continuous production prototype was constructed for further production verification. The experimental results show that the success rate of continuous production on this platform was 70.68%, with an average output of approximately 0.4kg/h for Taiping Houkui dry tea on a single slide track, and the produced tea was similar to manually made tea. This demonstrates that the continuous production technique has high feasibility and provides a reference for continuous production of Taiping Houkui tea.

Parameter impact on 3D concrete printing from single to multi-layer stacking

Previous studies have revealed that the design of printing parameters influences the filament shape, while the similarity degree between filament shape and modeled slice directly determines the precision of multi-layer stacking structures. This paper experimentally investigates the influence of printing parameters on filament shape and pressure along the printing path. Computational Fluid Dynamic simulation is employed to verify the experimental findings from the aspect of internal stress distribution. The results highlight the crucial role of printing pressure in connecting these parameters with filament shape. A settlement theory of the multi-layer structure is proposed and tested based the filament shape analysis. In practice, guaranteeing filament shape and adjusting printing progress can be achieved through proportional changes in nozzle travel speed and screw rotation speed. Controlling structure settlement is possible by adjusting nozzle height and time interval. These findings provide a solid foundation for the precise manufacturing of 3D printed structures.

Innovative hierarchical control of multiple microgrids: Cheetah meets PSO

The expansion of microgrids (MGs) comes from the increasing integration of renewable energy resources (RES) and energy storage systems (ESs) into distribution networks. However, effective integration, coordination, and control of Multiple Microgrids (MMGs) during energy transition from microgrid to grid, and vice versa presents a formidable challenge. This arises from the necessity to ensure smooth operation, coordination, and control of MMGs for stability and efficiency during transitions. The dynamic operation of MMGs due to intermittent renewable energy in microgrids and load variations presents an additional challenge for hierarchical control techniques. This paper provides an Artificial Intelligent (AI)-based control technique and introduces an innovative hybrid optimization technique, denoted as HYCHOPSO, derived from the fusion of Cheetah Optimization (CHO) and Particle Swarm Optimization (PSO) techniques, and the quantitative findings of extensive benchmark testing, constitute key aspects of novelty. The strategic choice of this novel optimization technique, coupled with a Proportional-Integral (PI) controller, provides key insights. HYCHOPSO is tested within benchmark functions and reaches its optimal score before 50 iterations as compared with optimization algorithms namely CHO, GWO, PSO, Hybrid-GWO-PSO, and SSIA-PSO which reaches after approximately 200 iterations. HYCHOPSO consistently exhibits the lowest mean values, indicating its robust convergence capabilities. The proposed control technique results in a significant reduction of the microgrid's Current Total Demand Distortion to 1.1%, meeting acceptable limits for a 600 V-bus According to IEEE519–2014 standard, even under nonlinear loads. Additionally, precise regulation of voltage and frequency is achieved with0.19%−+ deviations and a frequency overshoot of 1.9%. Furthermore, optimization contributes to seamless energy transition from microgrid to grid, achieving synchronization in less than 5 s. This enhances the real application's reliability, flexibility, scalability, and robustness. Furthermore, HYCHOPSO is introduced as an AI-based technique to facilitate control parameter design under dynamic conditions, with substantial simulation cases demonstrating control feasibility

Parameter design and effectiveness evaluation of wide strip mining of extra thick coal seams under dense buildings

In order to safeguard the surface structures from mining damage while optimizing the liberation of coal resources under the dense surface buildings of the Cedi River coal mine. Considering that the analysis of the structure and type of surface buildings and the geological mining conditions of the mine, a wide strip mining design with a retention width of 70 m and a mining width of 50 m was finally determined by using the pressure arch theory and Wilson’s theory, combined with the actual layout of working faces 51,002, 51,004 and 51,006 at the site.The strip mining design is verified by probability integral method and FLAC3D numerical simulation calculation respectively, The findings indicate that the highest value of earth surface subsidence created by the mining of the wide strip is 210 mm, the surface horizontal deformation value is 1.0 to − 1.4 mm/m, the damage to surface buildings is less than Level I, which satisfying the prerequisites of the surface building protection level, and can realize the continuous advancement of mine 51,002, 51,004 and 51,006 working faces, The coal pillars of the retained strip have sufficient support strength and long-term consistency, and the movement and deformation of the overburden after mining will not cause undulating subsidence of the surface, which effectively solve the mine's technical difficulties in safely coal mining under surface buildings.

Input-parallel output-series Si-SiC hybrid inverter with fractional harmonic elimination

This paper proposes an input-parallel output-series (IPOS) Si-SiC hybrid inverter with dual-frequency harmonic elimination modulation strategy. The proposed topology composed of two power conversion cells and a three-phase five-column medium-frequency step-down transformer, the low-frequency power conversion cell (LFPC-C, 1 kHz) leverages strong current-carrying capacity of silicon-based devices for dealing with the system main power, and the high-frequency power conversion cell (HFPC-C, 30 kHz) based on wide-bandgap semiconductor SiC devices is used to addressing the fractional harmonics compensation power. This topology combines the strong current carrying capability of Si devices with the low switching loss of SiC devices at high frequency and achieves high quality power conversion at low cost and low loss. Compared to existing “IPOP” Si-SiC hybrid inverters, this topology adopts a coupling step-down transformer on the output side of both LFPC-C and HFPC-C, which can effectively reduce current stress of HFPC-C SiC devices. Additionally, a dual-frequency harmonic elimination modulation strategy based on the topology is proposed to solve the fractional harmonics caused by the LFPC-C. The paper establishes a mathematical model according to the harmonic distribution characteristics of the LFPC-C and HFPC-C, and designs the system control schedules. Building upon the derivation of the voltage ripple model and the design of hardware parameters, Si IGBT and SiC MOSFET were selected for constructing a 7.5 kW prototype for testing, and the experimental results validate the feasibility of this topology and the accuracy of theoretical analysis.

Design, optimization, manufacture, and tests of CFRP hydraulic cylinder tube without metal liner: A bionic thorn‐tooth connection

AbstractHydraulic cylinders are widely used in rudder surface control, landing gear retraction of aircraft. The aircraft could benefit a lot on weight reduction, by the application of the carbon fiber reinforced polymer (CFPR) on the hydraulic cylinder. The design, optimization, manufacture of the CFRP hydraulic cylinder tube without metal liner is systematically studied in this article. In terms of structure design, inspired by natural thorn plants, a bionic thorn‐tooth connection structure is designed to connect CFRP and the metal end. Then the theoretical design method of thorn‐tooth is proposed. It also provides a new solution for the generic technology of CFRP‐to‐metal connection. In terms of CFRP parameters design method, an accurate mechanical model of CFRP hydraulic tube is established, the influence law of CFRP parameters on mechanical properties is explored, and the optimization method of CFRP parameters adapted to new characteristics is proposed. In terms of the manufacturing process, the split manufacturing‐combined molding process with high precision and low cost is developed to fit the characteristics of CFRP hydraulic tube without metal liner. The prototype manufactured by the proposed method has a weight reduction ratio of 62.37% while maintaining performances compared to the original metal hydraulic cylinder tube. This research will bring significant performance gains and considerable economic and environmental benefits to aircrafts.Highlights The systematic study of CFRP hydraulic tube without metal liner is presented for weight reduction. The bionic thorn‐tooth connection and its parameter design method are proposed. The CFRP parameters design method of CFRP hydraulic tube is established. A manufacturing process adapted to CFRP hydraulic tube without metal liner is developed.

Parameters design for feel system of aircraft active inceptor controller

To provide the pilot with feedback on flight states, aircraft active inceptor controllers deliver appropriate tactile feedback through the feel system. Current research on the feel system often relies on conventional models, with limited analysis of its unique characteristics. Investigating the dynamic properties of the feel system and their impact on flying quality can inform the parameters design of the feel system. In this paper, we designed various feel system parameters with different natural frequencies and damping ratios and selected three typical aircraft dynamic models. A human-vehicle closed-loop system model is established, including the pilot model, feel system model, and aircraft dynamic model. Combining different flying quality criteria, including bandwidth criterion, Neal-Smith criterion, and Open-Loop Onset-Point (OLOP) criterion, the flying qualities of Type I and Type II pilot-induced oscillations (PIO) are evaluated separately. The influence of aircraft configuration, feel system natural frequency and damping ratio on flying quality is explored. Finally, design recommendations for the feel system are proposed, aiming to reduce the adverse aircraft pilot coupling and improve flying quality.

Numerical investigation of disk bypass pipeline inspection gauge with hole in disk

Bypass Pipeline Inspection Gauges (PIGs) are widely employed as the most effective and economical devices for pipeline cleaning, maintenance, and inspection operations. The speed of these bypass PIGs significantly impacts the operational activities of pipelines. Very high or low PIG speeds may cause damage to the pipeline and the PIG itself. Therefore, it is important to control the speed of the PIG for better pigging operations. This study focuses on the influencing parameters and their impact on PIG speed. The approach of Computational Fluid Dynamics (CFD) has been utilized to model fully turbulent flow around a sample of a disk bypass PIG with a hole in the disk section for four different cases. PIG speed and pressure loss coefficient are measured to evaluate the effectiveness of the PIG. Meanwhile, two dimensionless groups are introduced based on the influencing design parameters for the movement of the disk bypass PIG, with and without a hole, to measure the optimal design parameters. The results show that a disk bypass PIG with a hole in the disk provides 5%-7% better results in terms of PIG speed and 6%-9% for the pressure loss coefficient around the PIG section. Among the four cases of a disk bypass PIG with a hole in the disk section, case-1 shows better pigging operation, with a dimensionless group value of 0.24. However, case-1 exhibits a 2.7%-22% reduction in PIG speed and a 12%-72% reduction in the pressure loss coefficient compared to other cases. Additionally, the lowest value of the presented dimensionless group indicates better pigging operation, and the optimal value of the dimensionless group is 0.24 for the design consideration of the PIG. This study holds directional significance for the design of the structural parameters of the PIG, which are useful for pipeline clean-up, inspection, and operational maintenance, and it provides reference value for related researches.