Dynamic Mission Profile Emulation for short-term reliability test of Submodule in Modular Multilevel Converter

For reliability improvements, a concept of test method called Mission Profile Emulation (MPE) has been proposed to recreate realistic loading conditions on Submodules (SMs) of Modular Multilevel Converters (MMCs). However, in most existing MPE, accurate dynamic emulation has not yet been achieved. The inaccuracy of dynamic emulation will result in the short-term reliability test, such as the temporary over-load operating test, cannot be correctly validated. Moreover, without proper dynamic responses, the MMC control strategies cannot be effectively validated as well. In this paper, a dynamic MPE method for SMs in MMC is proposed. In this method, the references for the testing system are accurately generated by a virtual MMC system, and the control bandwidth is widened by combining the MMC system in the control loop of the testing system. Finally, Simulation and experimental validations are given.