Small-signal model-based stability analysis for single-phase cascaded H-bridge STATCOM considering time delay

The paper develops a small-signal model for single-phase cascaded H-bridge (CHB) STATCOM, incorporating the time delay, and conducts a comprehensive stability analysis, encompassing eigenvalue analysis, participation factor analysis, and sensitivity analysis. In practice, relying on digital control technology, Static Synchronous Compensator (STATCOM) control has the inherent control delay problem of digital control, restricting the response characteristics and control accuracy of the system and affecting system stability. Most of existing studies are limited to analyze the impact of digital control delay on only one part of the control system. Therefore, the present work explores an analytical approach based on state-space modeling and investigates the global impact of such a delay on system stability by applying this method. Results of simulation and experiment verify correctness of the theoretical analysis.