Accurate and Stable Hardware-in-the-Loop (HIL) Real-Time Simulation of Integrated Power Electronics and Power Systems

Power hardware-in-the-loop (PHIL) technology allows for the testing of physical equipment in a real-time simulation environment. An important role is attributed to the power interface (PI). This PI connects a power system model, which is implemented on a digital computer, to physical hardware under test, such as a power electronic converter. Several hardware-in-the-loop (HIL) test setups with distinct PIs are proposed and compared. Based on detailed modeling of the different interfaces, system analysis is performed for each HIL test setup with respect to overall stability and accuracy. To verify stability for PHIL simulation systems, transfer function representations of the entire PHIL simulation processes are developed, and all involved time delays are quantified. The Nyquist stability criterion is applied to analyze all considered interfacing methods to enhance PHIL simulation stability, and the accuracy is evaluated. Moreover, experimental test results are given to demonstrate both the applicability and the functioning of the proposed interfacing methods. A particular focus is laid on the interfacing of physical power electronic inverters tested as part of a network in a PHIL real-time simulation.