CHATTERING REDUCTION IN DOUBLY FED INDUCTION GENERATORS USING SECOND ORDER SLIDING MODE CONTROL SCHEMES

Abstract

Wind farm are gaining attention in the present-day power industries. It employs the use of
Induction Generator (IG) with multiple variations and operation. The concept of variations
in pitch and speed respectively to control WT is referred to as Doubly-fed Induction
Generator (DFIG). Though, DFIGs are highly susceptible to instabilities. To address these
issues, a sliding mode control (SMC) scheme for a grid-connected wind turbine WT is
proposed to alleviate DFIGs susceptibility. Although SMCs have a major setback of
chattering. Second-order sliding mode (SOSM) control is presented to effectively mitigate
the chattering effect along the switching surface. Also, the scheme employs control laws to
ensure chattering free implementation of SOSM. The control scheme was designed to
exploit high wind penetration from the wind farm and ensure a maximum reduction in
overshoot. The systematic design approach of SOSM is presented, performance evaluation
between the controller was carried out. The work was implemented on a DFIG model, and
complete simulation of the system was carried out in MATLAB/Simulink_R2018a
environment. The result obtained was compared with a PI controller to show the
effectiveness of the control strategy.