Mission Profile Emulator for SMs in MMC Using Resonant Filter

Advanced assess and test close to real field operation are of great significance to ensure the reliability of Modular Multilevel Converter (MMC). Thus, Mission Profile Emulator (MPE) is proposed as an economical and efficient testing scheme, which aims to create emulated mission profile to submodules (SMs) of MMCs with simplified testing circuits. A challenge of MPE is to create testing current which has as small level of current ripple as the arm current in MMC. To limit the current ripple of the testing circuit, the existing methods try to increase the filter inductance of testing circuit. However, when the filter inductance increases to a certain level, the influence from the increase of filter inductance will be offset by the increase of DC supply voltage, and the current ripple will not be reduced anymore. As a result, a new MPE with resonant filter is proposed to further reduce the current ripple, meanwhile, a control strategy and a design method are proposed to cope with the resonant filter and achieve higher emulation accuracy. Simulation and experimental results are presented for the validation of the proposed method.