Transforming AC-Powered Production Machines for Operation in DC Microgrids: From Methodology to Realization

Manufacturing processes play a major role in the emission of greenhouse gases. To achieve the international goal of climate neutrality, it is necessary to decrease the amount of energy consumed by factories and their production machines. A promising approach is to improve grid efficiency and reduce voltage converter losses by using DC microgrids (DC-MGs). Furthermore, DC-MGs have proven suitable for an efficient integration of renewable energy producers and prosumers with energy recuperation capabilities. To establish DC-MGs successfully in production environments, it is necessary to provide solutions for DC-MG integration of AC-powered machines. This paper describes how to enable production machines originally designed for AC-grid use to be operated on industrial DC-MGs. The article focuses on a methodology for AC-DC transformation of machines, including definition of specifications, system analysis, and redesign. The methodology is described using the example of an injection-moulding machine. Finally, the results of the transformation process are evaluated.