Ph.D. student under the direction of R. ORTEGA

Thesis title: Stability analysis of electrical networks containing constant power loads.
Thesis abstract: This thesis is concerned with the stability analysis of electrical networks (ac, dc, and hybrid) containing constant power loads (CPLs), which model the behavior of tightly regulated devices such as controlled power electronic converters or motor drives in advanced automotive systems. A CPL is said to have a negative impedance characteristic, meaning that when the input current increases (decreases) the input voltage decreases (increases). It is well-known that this negative impedance characteristic has a destabilizing effect that gives rise to significant oscillations or to network collapse. With an ever increasing presence of electronic devices and CPLs, this is a particularly concerning problem in today's power grid. Within the last decade, a number of research works have been done to overcome the CPLs instability issue. However, most of that work was oriented to the study of small or device-level networks. Therefore, a comprehensive over-all stability analysis for large networks containing several CPLs remains an open problem. The objective of this thesis work is to analytically assess and warranty the stable operation of general electrical networks containing a set of distributed CPLs.