A Simple and Robust Sensorless Control Based on Stator Current Vector for PMSG Wind Power Systems

Abstract

This paper proposes a novel sensorless control based on the stator current vector for permanent-magnet synchronous generators in variable-speed wind energy conversion systems. In the proposed method, the rotor angle and speed are estimated indirectly from the stator currents, where only the stator inductance is required regardless of the stator resistance. In addition, the proposed method uses one current control loop to regulate the stator current magnitude, rather than two current control loops. To eliminate the current measurement noise, the second-order generalized integrator (SOGI) with a frequency-locked loop (FLL) is utilized, which can improve the estimation performance. The proposed sensorless control method with the SOGI-FLL is simple and easy to implement while achieving a fast and accurate estimation performance of the rotor angle and speed. The feasibility of the proposed method has been verified by simulation and experimental results.

Keywords

• Direct drive
• frequency-locked loop (FLL)
• permanent-magnet synchronous generator (PMSG)
• second-order generalized integrator (SOGI)
• sensorless control
• wind energy conversion system (WECS)