Time scale analysis and control of Wind Energy Conversion Systems

This paper presents a control method to design low-order optimal controllers for a high-order Wind Energy Conversion Systems (WECS) with Permanent Magnet Synchronous Generators (PMSG). Based on the nature of the WECS which consists of different time-scale (slow and fast) dynamics, the WECS is decoupled into slow and fast subsystems using time-scale analysis. Separate low-order optimal controllers are then designed for the slow and fast subsystems based on the Linear Quadratic Regulator (LQR) theory. The reduced-order optimal control of separate subsystems is compared with the high-order optimal control of the original system to show the superiority of the proposed method in terms of separation of dynamics and reduced computational effort.