公开(公告)号：US20200320234A1

公开(公告)日：2020-10-08

申请号：US16909753

申请日：2020-06-23

Applicant: HUNAN UNIVERSITY OF SCIENCE AND TECHNOLOGY

Inventor： Xiaoping ZHANG ,  Ji LIU

IPC: G06F30/20 ,  G05B13/04 ,  H02M3/158

Abstract: A mathematical model between the optimization objects and the optimization objectives is established, with finite-time control parameters as optimization objects, and a total harmonic distortion of an output voltage, a deviation signal of a capacitor voltage and a deviation signal of an output current of BBMC as optimization objectives. A multi-objective optimization satisfaction function and a multi-objective optimization fitness function are established. Multiple sets of optimal finite-time control parameters are iteratively optimized using an adaptive wolf pack algorithm. Functional relationships between respective optimal finite-time control parameters and the corresponding actual output current of BBMC are obtained using a numerical fitting method. Optimal control parameters corresponding to any load are obtained according to the obtained functional relationships. Therefore, the control parameters are adjusted in real time according to the functional relationships and the load of the BBMC-based speed regulation system or the actual output current of BBMC.

公开(公告)号：US20200131875A1

公开(公告)日：2020-04-30

申请号：US16731068

申请日：2019-12-31

Applicant: Hunan University of Science and Technology

Inventor： Buyan WAN ,  Yongping JIN ,  Xiaojun HUANG ,  Jialiang WANG

IPC: E21B25/06 ,  E21B25/18

Abstract: Disclosed is a process for drilling natural gas hydrates with a submersible core drilling rig using pressure wireline, including: 1) placing the drilling rig in seawater; 2) adopting a suction-press core drilling mode in a soft sediment formation, a suction-rotary core drilling mode in a medium-hard sediment formation, or a pumping direct circle-rotary core drilling mode in a hard sediment formation; 3) extracting a core; 4) recovering an inner tube for wireline pressure coring; 5) tightening a holding seal cap and storing the inner tube in a pipe storage rack; 6) punching; 7) capturing an inner tube for wireline pressure coring which is hollow and disengaging the holding seal cap; 8) lowering the inner tube; 9) adding a drill rod; 10) punching; 11) repeating steps (2˜10) till the core drilling reaches a given drilling depth; 12) recovering the drill rod and the drill; 13) recovering the corer.