Modeling and Feedback Compensator Design for Power-Hardware-in-the-Loop System for Medium-Voltage Grid-Connected Power Converters: Preprint

Hardware-in-the-Loop (HIL) evaluation is a method in which the test subject is split into a physical part and a simulated part, and these parts are connected with interfaces to form a combined physical-numerical system. Power-hardware-in-the-loop (PHIL) systems, where actual hardware is connected to a real-time model may exhibit issues of instability, inaccuracy and errors when operating in closed-loop. The challenge of generating a PHIL setup is that, firstly, because of the limited dynamic response of the different parts of the system, the test results may be inaccurate, and secondly, because of the high frequency noise introduced by the sensors to the closed-loop system, it may be difficult to design a compensator for the real-time emulator response, while stabilizing the closed-loop system at the same time. In this paper, different parts of a PHIL system are characterized, and the feedback compensator system design is proposed for stable operation of the closed-loop PHIL system. The issues as observed in a PHIL system without any compensator is demonstrated using experimental results. The effectiveness of a 1st order phase lead compensator is validated.