Building Experimental Twins Between Low and High Voltage Inverters Based on A Novel Per-Unit and Time-Angular Domain Conversion Technique

One common theme of today's electric power systems is the increased use of fast switching power electronic inverters. In the power electronics field, experimental or power-hardware-in-the-loop evaluations and testing are generally required before a new technology can be utilized. Nevertheless, it is usually expensive or impossible to build a large-scale, high-power, high-voltage power electronic inverter system, such as those used in a HVDC system or an offshore wind power system. Thus, the questions are: 1) Can we build a mini experimental system as a twin to investigate the performance of a high-power, high-voltage power converter system? 2) If this is possible, how should it be built? The aim of this paper is to establish a preliminary novel per-unit based theory, including a novel time to angular domain conversion technique, for research, controller design, performance evaluations of a grid-connected converter. With the newly established technology, a sample inverter system and its controllers can be designed and evaluated only once and then can be used as a mini experiment twin for scaled up or scaled down inverter systems for research and evaluation in a variety of applications. Electromagnetic simulation study demonstrates that the proposed per-unit-based experimental twin technique is effective for design and research of scaled-up and scaled-down grid-connected inverter systems. Furthermore, the novelly developed method is validated via hardware experiments.