A grid forming control strategy for STATCOM-assisted isolated SCIG-based wind energy conversion systems

Despite the many benefits, the remote wind energy conversion systems (WECSs) that operate using self-excited squirrel cage induction generators (SCIGs) suffer from poor voltage and frequency regulation. The current study establishes an efficient and feasible grid forming control structure to enhance the self-excited SCIG-based WECS’s voltage and frequency regulation. Apart from a fixed parallel excitation capacitor, the presented framework adopts a static compensator (STATCOM) as a reactive power (RP) compensator. The STATCOM’s operation frequency is forced in an open loop control to be constant, which makes the synchronous frequency of the SCIG match with the STATCOM in a steady state. In addition, the output voltage magnitude of the STATCOM is adjusted to balance the inductive and the capacitive RPs and improve the system voltage regulation by driving the needed RP. Moreover, this paper presents an active power (AP) control approach in which the speed of the SCIG’s prime mover is regulated to make the STATCOM’s AP zero. The designed power controller enhances the SCIG-based WECS’s frequency regulation by balancing the produced and consumed active powers. Simulation and experimental results reveal the presented framework’s accuracy and efficiency.