应用扰动观测器的定桨距风力机转速控制

Speed Control for Fixed-pitch Wind Turbine Using Disturbance Observer Method

目前,定桨距风力机在大功率应用场合采用恒速运行,若能采用变速控制,则可大大提高风能利用率。由于气动转矩与转速、风速间的非线性关系影响,在高风速区定桨距变速风力机的转速系统已变成一个不稳定的非线性系统。提出采用扰动观测器对气动转矩进行估计和补偿,以消除系统自身的不稳定性,使系统变成一个稳定的线性系统,并基于RT-LAB半实物实验平台设计了风力机的转速控制系统。实验结果表明:定桨距变速风力发电机组能够在设计风速范围内稳定运行,机组完全依靠应用扰动观测器的变速控制就能同时实现低风速区的最大功率点跟踪和高风速区的恒功率控制。

Fixed pitch wind turbine currently was controlled to constant speed in high power applications.Using variable speed control could greatly improve the utilization of wind energy.Because of the influences of the non-linear relation among the aerodynamic torque,rotational speed and wind speed,in high wind speed,the speed system of fixed-pitch variable speed wind turbines had already turned into an unstable non-linear system.The use of disturbance observer for aerodynamic torque estimation and compensation was presented,which was to eliminate the unstable factors in the system itself and make the system into a stable linear system.Then,the speed control system was designed based on the RT-LAB experimental platform-the-loop.The experimental results show that the fixed-pitch variable speed wind turbines can be operated stably in all operating wind speed and the speed control system have good at tracking changing wind velocity,which indicate that fixed-pitch variable speed wind turbine can be operated not only for maximum power point tracking（MPPT） in low wind speed but also for constant power control in high wind speed.