Modular Polyphased Full Order Current State-Space Model of the Modular Multilevel Converter

Abstract

This paper presents a new state-space model (SSM) to represent the four types of currents flowing through a Modular Multilevel Converter (MMC). In line with the converter topology, the model itself is modular. In other words, its configuration adapts itself to the number of AC phases, to the active or passive nature of the AC-side grid, to the connection between the AC and DC neutral points, and to the number of submodules. The model describes the influence of the MMC arm voltages on the currents using an average behavior of the submodules. Simulations performed using a software dedicated to electrical engineering systems demonstrate the value and the accuracy of the proposed model.