Stephan Adams

    PhD Student - Control of a Multiport Modular Multilevel Converter in a Residential Generation and Storage System

    Principal Supervisor: A/Prof Dezso Sera

    Associate Supervisor: Dr Mark Broadmeadow and A/Prof Geoff Walker

    PhD Overview

    Residential buildings have been using Distributed Generation (DG) to offset their CO2 emissions and reduce their electricity costs with the DG used by residential buildings being fuel cells and Photovoltaics (PV). The intermittent nature of PVs requires storage devices to achieve maximum self-consumption. These DGs and storage devices need to supply power to the consumer loads of the residential building, the grid, and the charging systems of electrical vehicles. One of the most promising methods of connecting the inputs (DGs and storage devices) and the outputs (consumer loads, grid, and EVs) is a multiport modular multilevel converter. This is a converter made up of modular components such that more inputs/outputs can be added/removed as desired. It has multiple outputs and inputs and can produce multiple (more than three) voltage levels so that their output filter can be reduced. There exists a range of MPMMCs that are being employed for high power static synchronous compensators (STATCOMs) utilized to compensate reactive power, battery management systems (BMS) or PV systems. In these systems centralized control structures are being used. These control structures do not easily allow for modularity or for the integration of different DGs and energy storage devices by modifying the direction of the power flow. Therefore, no control system exists that would allow a MPMMC converter to fully exploit its properties in a residential building. This project will evaluate the existing MPMMCs topologies to find the one that is appropriate for a power system in a residential building. It will then design a control system that will allow for modularity and the integration of different inputs and outputs by modifying the direction of the power flow. This report will set the background for MPMMCs in a residential context. It will also state the scope, significance and methodology of this project. It will also expound the primary literary review by explaining the inputs and outputs of a residential buildings power system, the power electronics associated with these inputs and outputs and finally a review of multiport modular multilevel converters.