Transient voltage performance and protection design of variable frequency ac three-stage generator for more electric aircraftCheng, Fangshun; Chu, Wenting; Li, Shangsong
doi: 10.1088/1742-6596/2785/1/012003pmid: N/A
Nowadays, variable frequency AC generation system is widely used on more electric aircraft because of their advantages of simple structure, high power density, and high reliability. However, a variable frequency system has a wide range of operating speeds and frequencies, and its exciter field is designed to be highly saturated at low speed. Under the condition of a saturated exciter field at high speed, the generator can produce a very high voltage, which will cause damage to aircraft utilization equipment, leading to catastrophic failures. Therefore, to protect the safety of the aircraft, transient voltage regulation performance and voltage protection design are critical in the system design of variable frequency AC generation. This paper focuses on the design of voltage regulation and protection of variable frequency electrical power systems that can meet airworthiness requirements.
Infrared Gas Sensor Based on MEMS Technology for Gas DetectionXiao, Ning; Li, Weichao; Tian, Yuewei; Wang, Weijun; Yuan, Chao
doi: 10.1088/1742-6596/2785/1/012103pmid: N/A
This paper presents an infrared gas sensor based on MEMS technology. The sensor can detect the input, output light intensity, and perform data processing. According to the corresponding results, the concentration of the gas to be measured can be obtained. The thickness of the protective layer and supporting layer of the infrared sensor transmitting unit can be changed. The proper size can make the transmitting unit work in a state of low deformation and high efficiency. The concentration of gas to be measured can be measured indirectly by using the sensor to detect the change of resistance of the unit. In this paper, the thickness of the protective layer and the supporting layer of the sensor transmitting unit is analyzed by finite element analysis. It is found that the thickness has a linear relationship with the deformation and temperature of the bridge deck. Further, it can be seen that when the thickness of the emission layer and the support layer is selected at the appropriate size, it has a good working state. Therefore, the sensor has good infrared emission intensity and stability. It has a broad application prospect in the early fire characteristic gas monitoring of cable.
Evaluation of soil accelerated corrosion of typical grounding materials used for electrical equipmentChen, Hao; Zhang, Tao; Qiao, Xin; Xie, Liming; Tan, Xiaomeng
doi: 10.1088/1742-6596/2785/1/012126pmid: N/A
At present, research methods for soil corrosion include sample weight loss methods, physical and chemical properties research, electrochemical research, indoor accelerated corrosion tests, etc. However, most existing soil corrosion evaluation methods have many drawbacks, such as high research costs, long experimental cycles, long results transformation cycles, and significant environmental limitations. In this paper, based on the electrochemical test results of environmental corrosion factors using typical grounding materials, a corrosion simulation solution load spectrum and an accelerated corrosion experimental system corresponding to the soil corrosion environment level were established. The accelerated corrosion samples were thoroughly studied and analyzed using macroscopic morphology observation, microscopic morphology analysis, and energy spectrum analysis. The results show that the soil accelerated corrosion method has strong stability and small deviation, which applies to the study of accelerated corrosion in the soil environment of grounding materials.
Research on the Wear Evolution Behavior of 20CrMnTi Alloy Steel under Different Loading ConditionsWu, Xiaolong; Du, Yaosen; Gao, Pengju; Tang, Xiaoren; Wang, Xiaosai
doi: 10.1088/1742-6596/2785/1/012158pmid: N/A
20CrMnTi alloy steel has excellent surface hardness and good wear resistance, making it widely used in the preparation of key components of various high-speed and high-load gearboxes, such as gear, rack, and bearing. However, the existence of friction and wear behavior in service leads to various damage behaviors, which seriously affects its service stability and effective life. Based on experimental research and numerical simulation technology, this study reveals the damage evolution law of 20CrMnTi low carbon alloy steel under different wear load conditions. It is shown that the increase of wear load and time duration will obviously lead to the increase of contact stress and deformation of the material surface, and eventually lead to an increase in wear degree. The research findings provide experimental support and theoretical guidance for effectively predicting the damage law in actual service.
Development and Application of Substation Grounding Grid Topology Detection and Recognition SystemJi, Wangwei; Lin, Yi; Li, Guocheng
doi: 10.1088/1742-6596/2785/1/012078pmid: N/A
To solve the problem of substation grounding grid faults difficult to diagnose in the case of non-power non-excavation, based on the inductive apparent magnetic resistance method developed a set of grounding grid topology detection and identification systems, to achieve non-destructive detection and real-time imaging of the grounding grid location, structure, breakpoints, and other information to identify and rebuild the topology of the grounding grid. The paper introduces the system design and practical experiments and applications in a substation in Guangzhou City, the system has achieved good application results, reaching the level of engineering prototype, the development of the system device has a good practical significance, and has a broad application prospect.
Power Network Vulnerability Assessment Based on Electric Power System Cyber Security Simulation PlatformChen, Chenxi; Shi, Kewei; Xiao, Yizhao; Tang, Fei; Gong, Lianghua
doi: 10.1088/1742-6596/2785/1/012094pmid: N/A
This paper introduces a modeling approach for the integration of electric power and information networks, along with the creation of an electric power system network simulation platform. The system, achieved through the deep integration of computation, communication, and control technologies, offers new insights into power grid intelligence. The paper discusses the concept of power system vulnerability and presents a modeling scheme that effectively simulates and analyzes power systems. Using the Analytic Hierarchy Process (AHP), the impact of cyber attacks under different load conditions is evaluated, revealing that attacks have more severe consequences under heavy loads. In conclusion, this research contributes to enhancing the security and stability of power systems.
Study on the mathematical model of the novel drum worm pairLi, Shuangcen; Xiao, Linglin
doi: 10.1088/1742-6596/2785/1/012117pmid: N/A
A lot of work is needed to investigate the design method of planar internal gear enveloping drum worm (PIGEDW). Firstly, based on the gear meshing theory, the meshing equation is deduced. Secondly, the PIGEDW mathematical model is established by MATLAB. Finally, the influence of the inclination angle of the generating plane on the meshing performance of PIGEDW is analyzed. The results show that appropriate changes in geometric parameters are beneficial in enhancing the performance of PIGEDW, which provides a way to optimize its design.
Optimization Design of Semi-active Suspension for Vehicles Based on LQR Optimal ControlLiu, Lianming; Calderon, Aldrin D.
doi: 10.1088/1742-6596/2785/1/012005pmid: N/A
The suspension system is crucial for providing a comfortable ride and ensuring smooth driving. This article presents a random road surface model and a 1/4 vehicle two-degree-of-freedom semi-active suspension model. The optimal control performance index function was obtained by using the minimum principle, and the optimal controller for semi-active suspension was designed. Simulations were conducted in MATLAB/Simulink, using vehicle acceleration, suspension dynamic deflection, and tire dynamic deformation as evaluation indicators. The study found that the vehicle’s acceleration, suspension dynamic deflection, and tire dynamic deformation were reduced by 21.79%, 21.86%, and 9.88%, respectively, with the use of the designed semi-active suspension optimization controller. This resulted in improved driving smoothness and riding comfort.
Influence of Wire Feeding Speed on the Morphology and Properties of Stainless Steel Laser Welding JointsLiu, Shuai; Luo, Ziyi; Liu, Weiqing; Wang, Yuzheng; Cai, Detao
doi: 10.1088/1742-6596/2785/1/012052pmid: N/A
Using laser filler wire welding technology, welded joints were produced at varying wire feeding speeds. The microstructure and mechanical attributes of these joints were then examined through optical metallography, scanning electron microscopy, universal tensile testing, and microhardness testing. It demonstrates that superior surface formation and defect-free welded joints can be achieved through the filling wire welding process. The main components are austenite and ferrite, with slightly varying morphology and content. Through the results of tensile tests and fracture microstructure scanning, when the rate of wire supply is 2.0 meters per minute, the tensile strength reaches 650 MPa. The second phase particles were discovered in the fracture scan. According to microhardness measurements, the overall hardness of the welded joints at different wire feeding speeds is higher than that of the base material.