Sliding mode sensorless control of wind turbine pitch motor with ESO feedforward compensation in the offshore wind power system

Abstract

In order to improve the dynamic performance of the control system, a variable frequency sliding mode sensorless control strategy based on Extended State Observer (ESO) feedforward compensation was proposed in order to improve the disturbance and jitter problems of pitch motors in offshore wind power generation systems. The fast exponential reaching law is designed in the velocity loop, and the integrated sliding surface is adopted, which reduces the steady-state error of the traditional sliding surface and weakens the jitter phenomenon of the moving point on the sliding surface. The traditional sliding mode observer is improved, and the variable cut-off frequency filter is used instead of the low-pass filter in the filtering process to filter the signals of each speed band. At the same time, in order to estimate the disturbances in the system, the Linear Extended State Observer (LESO) is designed to observe and compensate for the unknown disturbances, which improves the robustness of the system. The simulation results show that the control strategy in this paper solves the problems of traditional Sliding Mode Control (SMC), which not only shortens the response time of the system, but also significantly improves the anti-disturbance performance of the system, and the overall effect is significantly improved.

Keywords

• change the cutoff frequency
• fast exponential reaching law
• extended state observer
• sliding mode observe