Modular Experimental Plant for Industrial DC Grid with Controlled Electrical Drives

The Paper presents the concept of an experimental plant, which is to be built within the framework of the research project DC-INDUSTRIE2. This system consists of a multitude of electrical drives, various uni- and bidirectional rectifiers, several decentralized energy suppliers and several energy storage units. All devices in this system are coupled via a common DC Grid. DC Grids allow a very simple bidirectional energy exchange between the connected devices. Therefore, braking energy in electric drives, for example, can be used without additional effort and the integration of decentralized energy supplier systems such as photovoltaic (PV) or combined heat and power plants (CHP) as well as energy storage systems is much easier than in AC Grids. The purpose of the experimental plant is to electrically emulate a typical production machine or process and to investigate the real occurring currents and energy flows in the DC Grid. A total of 11 drive sets are available for this purpose, each consisting of a test machine and a load machine. The modeling of the actual production machine is done in MATLAB/Simulink. Speed and torque curves are calculated here and transmitted to the drive inverters via fieldbus. Thus, not only real mechanical quantities are obtained at the shaft, but also the currents in the DC Grid correspond to those of a real plant. Therefore it can be investigated, for example, how a production machine converted from AC to DC power would behave without having to build it. Furthermore, the effects of storage connections and grid disturbances can be realistically investigated.