Transient EMI Analysis of a Submodule of Modular Multilevel Converters Based on Discontinuous Galerkin Time-Domain Methods

Modular multilevel Converters (MMCs) are widely adopted in high voltage direct current transmission (HVDC) systems for their small magnitudes of harmonics, compact structures, and many other advantageous properties. However, MMCs are faced with serious electromagnetic interference (EMI) induced by the switching actions of semiconductor devices. Classic finite element method, which demands inverts of large mass matrices in time-domain analysis, is often unaffordable. In this manuscript, we carry out the transient EMI analysis of a MMC submodule via the discontinuous Galerkin time-domain method, which allows explicit time integration and is free of the solution of large linear equations. Numerical results reveal the superior efficiency of DGTD method over FEM, and that the electric field intensity is the primal concern in EMI optimization.