Designing a low frequency oscillation stabiliser for wind turbine type-4 based on the phase compensation method

A stabiliser is designed based on the phase compensation method to suppress the instability of wind-turbine type-4 in the low frequency mode [direct current voltage loop mode and phase-locked loop mode]. Referring to the second-order equation of synchronous generator rotor motion, the authors simplify and reconstruct the full-order linearised model of wind-turbine type-4 and establish a current source damping torque model suitable for analysing the stability of the direct current voltage loop and phase-locked loop. By analysing the damping phase of the direct current voltage loop and phase-locked loop, introducing a phase compensation loop, and adjusting the phase and amplitude of the damping transfer loop, the authors could effectively enhance the damping of the direct current voltage loop and the phase-locked loop and suppress the low frequency oscillation of wind-turbine type-4. The stabiliser is introduced into the linear model and the time domain simulation model. The effectiveness of the stabilisers is verified by the eigenvalue analysis and time domain simulation results.