PROJECT TITLE :

Static Synchronous Generator Model: A New Perspective to Investigate Dynamic Characteristics and Stability Issues of Grid-Tied PWM Inverter

ABSTRACT:

With increasing penetration of the renewable energy, the grid-tied PWM inverters need to require corresponding responsibilities for the protection and stability of future grid, behaving like conventional rotational synchronous generator (RSG). Thus, recognizing the inherent relationship and intrinsic differences between inverters and RSGs is essential for such target. By modeling the everyday electromechanical transient of grid-tied PWM inverters, this paper 1st proves that PWM inverters and RSGs are similar in physical mechanism and equivalent in mathematical model, and therefore the concept of static synchronous generator (SSG) is thereby developed. Furthermore, the excellent comparison between RSG and SSG is dispensed well, and their inherent relation is made. Based mostly on these findings, the rationality and feasibility of migrating the ideas, tools, and ways of RSG stability analysis to research the dynamic behaviors and stability problems of SSG is therefore confirmed. Taking stability problems as an example, the criteria of little signal and transient stability of a typical grid-tied PWM inverter is place forward to demonstrate the significance of the developed SSG model (including synchronizing coefficient, damping coefficient, inertia constant, and power-angle curve), providing clear physical interpretation on the dynamic characteristics and stability problems. The developed SSG model promotes grid-friendly integration of renewable energy to future grid and stimulates interdisciplinary analysis between power electronics and power system.