Research on Short Time Scale Failure Mechanism of MMC Sub-module Busbar

Laminated busbar have the advantages of low impedance, good anti-interference, high reliability, space saving, easy installation, fast and so on. As a high-power modular connection component, it is widely used in wind power, photovoltaic, electric power and hybrid traction, power generation Systems, power switch systems, power conversion modules of electric equipment and other places. And it is indispensable part for the development of the power industry. Therefore, in the connection part of MMC sub-modules, laminated busbar are also used. This article first uses FEM Software to extract the stray inductance of the busbar of the module, highlighting the advantage of low stray inductance of the laminated busbar. Taking into account the DC short-circuit fault between the sub-modules, the temperature rise and deformation of the busbar caused by voltage changes are analyzed by using the electric field-heat transfer-structure three-field coupling method. And by changing the voltage level of the busbar and the operating time under a certain voltage level, the safe operating domain of the laminated busbar was judged, and the safe operating time and voltage were obtained.