Southeast University

Stoneferry Technology, LLC

Sinoma Science & Technology Ltd.

Sinoma Science & Technology Co. Ltd.

Jianzhong Zhang

Qian Zhao

Youjiang Wang

Liquan Zhang

Hongwei Guo

FuJin Deng

Zhong-Xing Mi

ChengKai Liu

Ning Kuang

Fangtian Hu

Yun Zhou

Hanlu Zhang

The present invention discloses a method for modeling sequence impedance of a modular multilevel converter (MMC) under phase locked loop (PLL) coupling. The method includes the following steps: S1, establishing a circuit topology model; S2, establishing a PLL output characteristic model; S3, establishing a PI controller output control small signal model under a dq axis; S4, deducing a modulation small signal; and S5, calculating MMC port impedance. According to the method, a precise MMC port impedance model is established by analyzing a double mirror frequency coupling effect in the output of a modulation signal in a control link caused by a phase angle disturbance and comprehensively considering the combination of the multi-harmonic coupling effect of an MMC. On one hand, the proposed modeling method aims at a common MMC adopting current closed-loop control, in which a half-bridge sub-module is adopted, a circuit topological structure and a control structure are both more common, and a mathematical model is easy to establish. On the other hand, the physical significance of an impedance analysis method is clear, the modeling process is modular and is easy to understand and implement, and the inverter port impedance can be measured on site, so that the correctness of theoretical modeling can be conveniently verified.

Method for modeling sequence impedance of modular multilevel converter under phase locked loop coupling

The present invention relates to a three-dimensional woven hollow layer-connecting fabric, comprising an upper layer-surface () formed by crossing upper ground warp yarns (), () and a weft yarn () and a lower layer-surface () formed by crossing lower ground warp yarns (), () and a weft yarn (); the weft yarns () and () on the upper and lower layer-surfaces are also crossed with poil warps (), () besides ground warp yarns (), () and (), () on their own layer-surface; the spatial walking direction of poil warps (), () woven from one layer-surface to another is opposite to the weft-inserting direction of the fabric. The framework feature of the composite layer-connecting fabric of the present invention is distinct, and the vertical support function of poil warps between two layer-surfaces is good. The spatial structure of the layer-connecting fabric is varied in conformation, easy to design and adapted to produce on a large scale. The compositely-strengthened material has the characteristics, such as anti-corrosion, anti-penetration, light weight and excellent physical mechanical properties.

Three-dimensional woven hollow layer-connecting fabric

A method for fabricating multilayer fabrics having a prescribed integration pattern and an apparatus of implementing same. In one embodiment, the method include the steps of providing a plurality of winding yarn carriers arranged in a multilayer structure along a first direction and configured such that each winding yarn carrier is operably movable with respect to one another along a second direction that is perpendicular to the first direction, forming a plurality of crossover points of the winding yarns by moving at least one winding yarn carrier along the second direction according to the integration pattern, transporting the binder yarns through the plurality of winding yarn layers at predetermined locations along the first direction, and locking the binder yarns in place, pushing the binder yarns toward the fell of the multilayer fabrics, and taking up the formed multilayer fabrics.

Method of forming integrated multilayer fabrics

Growing community of inventors

Nanjing, China

Jianzhong Zhang