RT23 | Insights on laboratory-scale DC system validation with PHiL and RCP

The presentation aims to present the current state of the laboratory-scale DC system implementation located at Ostfalia University in Wolfenbüttel, Germany. It is used to validate operation, control, and protection principles especially of HVDC systems. The system consists of a MMC test bench from OPAL-RT, which serves as a hardware demonstrator with RCP capabilities, and a Spitzenberger and Spies linear amplifier connected to an OP5707 that serve as a PHiL setup. An additional Triphase PM15 switched amplifier is used to enhance the configuration even further. The following topics will be covered in the presentation: An overview of the laboratory environment and its applications (lab-scale HVDC validation, and MVDC validation, for example for ship vessels) will be given. Then, the performance of MMC PHiL simulations will be described, where the real-time simulation performance of Type 4 MMCs is analyzed by comparing classical toolboxes and solvers with Artemis, leading to the statement that using Artemis results in the better computational performance. Then, a method to measure and estimate delays of the PHiL test bed with simple but sufficient setups will be shown. The test bed can be characterized precisely, including the sequence of execution of real-time simulation and communication. Finally, one application example will be given, where the benefit of having access to the voltage balancing algorithm on the CPU while preserving the PWM resolution from the FPGA is shown. This is currently implemented on the MMC test bench by OPAL-RT, and will be used to validate capacitor voltage estimation algorithms that are developed together with the DLR Institute of Maritime Energy Systems.