Multifunctional modular multilevel converter-based systems bottom-up approach to system design

Abstract

This paper introduces a new power system that can be implemented on all levels by using the bottom-up approach of system design. It is based on orthogonal power flow at different frequencies. The power exchange between different elements of the grid as well as the additional features are based on implementing power electronics (PE) interfaces and applying multiple frequencies (zero- DC is also a valid frequency). Thus, the micro-grids are decoupled into multiple systems which can then be controlled independently, paving the way for a more flexible and stable general system. By implementing multiple frequencies (MF) additional features can be achieved that would otherwise not be possible with conventional AC, newly- emerging DC systems or any of their hybrid forms. In this paper, the concept of orthogonal power transfer, which is the basis for this system will be presented, and the multifrequency system will be defined and compared to existing solutions. Finally, this novel concept will be demonstrated on a simulation incorporating renewable energy sources, energy storage and a constant power load.