Speed Estimation in PMSG-Based Wind Turbines From DC Voltage Measurement

The aim of this work is to propose a sensorless methodology in order to estimate the rotational speed of wind turbines (WTs) equipped with permanent magnet synchronous generators (PMSGs). The suggested methodology is based on the measurement of the direct-current (dc) voltage at the output of a three-phase diode bridge rectifier, which is connected to the stator of the PMSG. The presented methodology has the advantage of reducing the number of required sensors to estimate the rotor speed of PMSG-based WTs since only one voltage sensor is needed. The methodology is validated by means of simulations in MATLAB-Simulink and experimental tests on PMSGs with different sizes, operating under different speed regimes and load conditions. The results show that the proposed methodology is able to estimate the PMSG speed with good accuracy.