Page 139 - Hybrid-Renewable Energy Systems in Microgrids
P. 139
Study of control strategies of power electronics during faults in microgrids 123
Figure 7.5 (Continued)
conditions. Therefore, the use of dual-sequence current controllers is proposed by
Ref. [6]. This method applies two sets of PI controllers, one regulating only positive-
sequence current in positive-sequence reference frame and the other controlling only
negative-sequence current in negative-sequence reference frame, allowing the current
in different sequences to be controlled within its own reference frame.
3.3.2 Stationary reference frame control
Stationary reference frame control, also referred to αβ-control, regulates control sig-
nals in stationary two-phase frame. Proportional-resonant (PR) controllers are typi-
cally used in αβ-control, which can be expressed by [9]:
