Magnetic Field Simulation and Measurement of MMC Submodule Under Dual Pulse Test

Modular multilevel converter(MMC) is widely applied to the UHVDC power transmission system for its advantages of bidirectional power transmission, power qualities, and flexible controls. With a large number of insulated gate bipolar transistors(IGBTs) utilized in MMC converter stations, an extremely complicated electromagnetic environment is generated due to the dv/dt and di/dt during the IGBT switching process. A finite element method(FEM) is adopted to calculate the dual pulse magnetic field generated by the 4.5kV/5kA IGBT MMC submodule during the dual pulse testing process. Then, a dual pulse test is conducted and the pulse magnetic field is measured to verify the simulation result. Finally, a fast Fourier transform (FFT) analysis is performed to give a comprehensive view of the switching process and its mechanism as an electromagnetic interference source.