公开(公告)号：US20220320865A1

公开(公告)日：2022-10-06

申请号：US17642240

申请日：2021-06-29

申请人： HEFEI UNIVERSITY OF TECHNOLOGY

发明人： Xing ZHANG ,  Zixuan GUO ,  Shaolong CHEN ,  Yang WANG ,  Hailong PAN ,  Qian GAO ,  Zhen XIE

IPC分类号： H02J3/24 ,  G05B19/042

摘要： A stability control method for a virtual synchronous generator (VSG) in a strong grid based on an inductance-current differential feedback is provided. A grid-connected topological structure of a VSG using the control method includes a direct-current (DC)-side voltage source, a three-phase inverter, a three-phase grid impedance and a three-phase grid. By controlling the VSG and controlling the inductance-current differential feedback, the method suppresses the oscillation of the output power from the VSG in the strong grid and implements the stable operation of an inner-loop-free VSG in the strong grid, without adding the physical inductance, increasing the cost of the filter and additionally providing a grid-side current sensor.

公开(公告)号：US20220352726A1

公开(公告)日：2022-11-03

申请号：US17764210

申请日：2021-05-13

申请人： HEFEI UNIVERSITY OF TECHNOLOGY

发明人： Xing ZHANG ,  Ming LI ,  Zixuan GUO ,  Jilei WANG ,  Hailong PAN ,  Yang WANG ,  Qian GAO ,  Fei LI

IPC分类号： H02J3/46 ,  G06F17/14

摘要： A dual-mode combined control method for a multi-inverter system based on a double split transformer is provided. For an extremely-weak grid, the method provides the dual-mode combined control method for a multi-inverter system based on a double split transformer. According to the method, the equivalent grid impedance at a point of common coupling (PCC) of one grid-connected inverter (GCI) in the multi-inverter system based on the double split transformer is obtained with a grid impedance identification algorithm, and the system sequentially operates in a full current source mode, a hybrid mode, and a full voltage source mode according to a gradually increasing equivalent grid impedance, thereby effectively improving the stability of the multi-inverter system based on the double split transformer during variation of the strength of the grid. The method ensures that the system can still operate stably in the extremely-weak grid.