Sensorless Control of Permanent Magnet Synchronous Generators in Variable-Speed Wind Turbine Systems

This paper proposes a sensorless control strategy for permanent magnet synchronous generators (PMSGs) in variablespeed wind turbine systems (WTSs). The proposed scheme uses an extended Kalman filter (EKF) for estimation of rotor speed and position. For EKF design, the nonlinear state space model of the PMSG is derived. Estimation and control performance of the proposed sensorless control method are illustrated by simulation results for all operation conditions. Moreover, the performance of the proposed EKF is tested under variations of the PMSG parameters. NOTATION N,R,C are the sets of natural, real and complex numbers. x ∈ R or x ∈ C is a real or complex scalar. x ∈ R (bold) is a real valued vector with n ∈ N. x> is the transpose and ‖x‖ = √ x>x is the Euclidean norm of x. 0n = (0, . . . , 0)> is the n-th dimensional zero vector. X ∈ Rn×m (capital bold) is a real valued matrix with n ∈ N rows and m ∈ N columns. O ∈ Rn×m is the zero matrix. xz ∈ R is a space vector of a stator (s) or filter (f ) quantity, i.e. z ∈ {s, f}. The space vector is expressed in either phase abc-, stationary s-, or arbitrarily rotating k-coordinate system, i.e. y ∈ {abc, s, k}, and may represent voltage u, flux linkage ψ or current i, i.e. x ∈ {u,ψ, i}. E{x} or E{X} is the expectation value of x or X , respectively.