Modular Multilevel Converter-based Arbitrary Wave shape Generator used for High Voltage Testing

This paper analyses different design trade-offs for a Modular Multilevel Converter (MMC)-based Arbitrary Wave shape Generator (AWG) used for High Voltage (HV) testing and certification of grid assets such as transformers, switchgear, and cables. Modulation techniques, number of submodules, output voltage levels, arm inductance, and series damping resistance play an essential role in obtaining different waveforms with good quality. Phase-Shift Carrier (PSC) modulation technique proves to be a superior modulation technique for different periodic waveforms over Nearest Level Control (NLC), even when a large number of submodules is considered. With the traditional second-order filter design strategy, proper values of the arm inductance and series resistance can be selected, guaranteeing a good quality of the generated voltage waveforms to verify different dielectric properties of grid-assets. The design of such an AWG is demonstrated with the simulations in MATLAB-Simulink.