Multimodular multilevel rectifier/inverter link with independent reactive power control

The feasibility of a DC link made up of multimodular, diode-clamped multilevel power converters to form the rectifier and the inverter has been studied in this paper. Equalization of the DC capacitor voltages is accomplished by auxiliary DC choppers sized at 10% of the current ratings. Real power control makes use of voltage angles as the control levers. Independent reactive power control on both sides makes use of voltage magnitude control. Digital simulations demonstrate the success of local controls. As the rectifier/inverter link plays a pivotal role in the unified power flow controller (UPFC) and the asynchronous DC link, the study has shown that multimodular multilevel versions of these FACTS controllers are feasible.