Stability of DC/DC three terminals converter using Modular Multilevel Converters for HVDC systems

This paper presents the modelling and control of a DC/DC bidirectional converter with 3 terminals based on Modular Multilevel Converter (MMC) suitable for high voltage and power applications in multi-terminals high voltage direct current (MT-HVDC) grids. A proof is given in order to guarantee the global stability of the system by means of Lyapunov theory and switching control theory. In addition, a study on how to improve the generated harmonics is shown.