PID-type terminal sliding mode control for permanent magnet synchronous generator based enhanced wind energy conversion systems

Abstract

The provision of wind farm (WF) grid-codes (GC) in sustaining grid operations has become imperative, especially for WFs with permanent-magnet synchronous generator (PMSG) wind energy conversion system. Numerous techniques are developed for executing GC requirements in the event of grid faults. Among the methods, an intriguing strategy is to enhance the performance of back-to-back (BTB) converter controllers. In this research, the PID-type terminal sliding mode control (PID-TSMC) scheme is implemented for both machine-side and grid-side converter modified controllers of BTB-converter, to reinforce the nonlinear relationship among the state-variable and control input. The application of this control scheme decreases the response time and improves the robustness of the BTB-converter controllers to parameters uncertainty and external disturbances. The grid-side converter tracks the maximum power point, contributing to the generator active power output rapid decrease during faults. This frees up converter capacity for injecting GC-compliant reactive current into grid. Besides, the machine-side converter regulates dc-link voltage, in which its variations during external disturbances decrease substantially with the PID-TSMC. The discussions over the simulations contemplate on the robustness and efficiency of the implemented PID-TSMC strategy in comparison to other BTB-converter control strategies.