Integration Design of Sub-Module for Medium Voltage Modular Multilevel Converter

This paper presents the integration design of the Sub-Module (SM) intended for Modular Multilevel Converter (MMC) in Medium Voltage (MV) application. A hardware prototype with modular design of the SM with Insulated-Gate Bipolar Transistor (IGBT) in half-bridge configuration is developed to demonstrate the quality of the signal interface. Simplified digital signal techniques are used to transfer the gate control signals from a main controller to the SM, and the transfer of measurement of the SM capacitor voltage to the main controller. The presented results consider the ElectroMagnetic Compatibility (EMC) of the simplified interface by introducing noise sources expected to be significant in a fully implemented MMC. The main benefit of the approach with a simplified signal interface is reduced complexity compared to distributed control strategies and alternative interfaces, making the MMC an even more attractive option in MV applications. The implementation achieves good noise immunity through the signal interface SM during switching operation, and in the presence of external noise sources.