A5100447575- Advanced DC-DC Converters
- Multilevel Inverters and Converters
- Rock Mechanics and Modeling
- Geomechanics and Mining Engineering
- Geoscience and Mining Technology
- Microgrid Control and Optimization
- Geotechnical Engineering and Underground Structures
- Dam Engineering and Safety
- Electromagnetic Launch and Propulsion Technology
- Tailings Management and Properties
- Grouting, Rheology, and Soil Mechanics
- Advanced Battery Technologies Research
- HVDC Systems and Fault Protection
China University of Mining and Technology
2016-2022
China Institute of Water Resources and Hydropower Research
2021
Abstract This paper studies the width of narrow coal pillars, mining‐induced failure characteristics, and surrounding rock control effect gob‐side entry driving (GED) adjacent to 2‐1208 filling working face with an approximately 900 m depth. Laboratory experiments, numerical simulations, loosening circle tests, engineering practices are conducted. The mechanical properties body, distribution evolution law second invariant deviatoric stress ( J 2 ), variation in plastic zone GED studied....
Multi‐coal‐seam mining creates surrounding rock control difficulties, because the of a coal face in one seam can affect faces another. We examine effects multi‐coal‐seam on evolution deviatoric stress distribution and plastic zone roadway rock. In particular, we use numerical simulation, theoretical calculation, drilling detection, mine pressure observation to study characteristics Tailgate 8709 No. 11 Jinhuagong when N8707 N8709 7‐4 are mined. The laws advance behind sections studied,...
In order to better study the movement principles of overlying strata during backfill mining, we established a thin plate model on an elastic foundation with boundary main roof. And by finite difference method, variation roof’s principal moments and maximum subsidence ω 0 coefficient k 1 coal seam, 2 body, thickness h , Young’s modulus E Poisson’s ratio μ roof are calculated studied. Using these calculations, were able determine that had three bending moment extreme points, including M zz in...
Pulse train (PT) controlled switching DC/DC converters possess advantages of simple structure, fast dynamic response, good robustness etc. but also accompanied by undesirable low-frequency oscillation phenomenon when the are operated in continuous conduction mode (CCM). To mitigate oscillations PT buck converters, a novel converter with coupled inductor is proposed this paper. Firstly, mechanism analysed, corresponding suppression method discussed and discrete-time model constructed....
Abstract Controlling the surrounding rock of main roadway passing through a goaf during reconstruction and expansion merger reorganization mine is common challenge in underground mining practices. In this study, combined support technology roof “anchorage‐mesh‐shotcrete” double‐H‐type space frame structure for was studied using field investigations, theoretical analysis, engineering practice. It observed that control difficulties lie strongly mining‐induced strata early stages, with...
This study reports a new slow-scale bifurcation phenomenon in linear frequency of power factor correction (PFC) cascade converters, which will offer useful design reference for PFC application. Compared with the resistive loads analysed before, stability converters is studied, are more complex but practical. has introduced research method that secondary efficient point-of-load converter can be equivalent to constant load. Based on this method, small-signal model whole system constructed and...
In the conventional boost converter with pulse train (PT) control, output voltage will produce undesirable low-frequency oscillation in continuous conduction mode. To alleviate problem, this study proposes a novel which much more energy can be delivered when is less than reference and vice versa, delivery suppressed. The response speed of proposed greatly improved reduced. Firstly, PT-controlled analysed. Furthermore, operating principles are studied. Then processes start-up load switching...
Although multi current-valley control can be used to eliminate the low-frequency oscillation for pulse train controlled DC/DC converters operated in continuous conduction mode (CCM), number of preset values are necessarily increased, which will increase complexity controller. Meanwhile, output voltage ripple is uncontrollable and varies with changes load. Thus a sliding based PT (SCV-PT) method proposed this paper. The approximate discrete-time models SCV-PT derived theoretical analysis....
Power factor correction (PFC) converters possess high complexities due to the introduction of series connections among power converters, which adversely affects stability PFC system. On assumption that input voltage can be replaced by its RMS value, and frequencies inductor current output primary converter are much lower than switching frequency converter, simplified analytical circuit cascade is established with average control. As for secondary equal a constant load, based on small-signal...
Abstract At present, in the relevant design specifications for earth-rock fill dams China, filling standard of rockfill materials is expressed by porosity. Although mechanical properties coarse-grained soil are closely related to its porosity, with different gradations not same even if porosity same. Porosity can’t express compactness, while relative density can represent compactness soil. In order control deformation reasonably, it necessary carry out field test materials. this paper,...