Near Magnetic Field EMI Analysis and Modeling for a MMC Submodule

The fast switching of power electronics devices inside the submodule of modular multilevel converter (MMC) could causes severe electromagnetic interference (EMI), and the EMI current flowing in power modules and busbars excites non-negligible near-field magnetic emission. This paper analyzes the magnetic field excited by the main circuit of MMC submodule under double-pulse test with the aid of finite element (FE) simulation. The main magnetic emission sources and radiation characteristics are discussed based on the FE results and verified by near-magnetic field measurement. Also, simplified equivalent models of the laminated busbars and power modules are proposed, which can evaluate their magnetic emission quickly and accurately.