全液压海上风力机最大气动能量捕获的控制策略

Maximum Aerodynamic Energy Capture Strategies for Hydrostatic Offshore Wind Turbines

提出了以海水为传递介质的开环液压传动系统并应用于漂浮式风力机,建立了风力机转子、液压传动系统及发电机的数学模型。利用比例–积分–微分控制器控制系统改变液压泵排量、调整变量泵转矩以实现风力机转子最大气动能量捕获的控制策略。以5MW漂浮式风力机样机为例进行了时域建模仿真,研究了该系统在额定风速下的响应。研究结果表明:当风速在额定值11.4m/s以下时,通过提出的控制系统,能够使变量泵产生的反作用转矩接近于风力机气动转矩的最优值,获得的叶尖速比接近最佳值8.1,保证叶轮捕获最大气动能量。通过对风力机转子捕获的气动功率及发电机的输出功率的动态特性进行分析比较,可知该液压传动系统的传递效率为80.2%。

A new open-loop hydraulic transmission system was applied in offshore wind turbines, in which seawater was used as the working fluid. The mathematical modal comprising the wind turbine rotor, hydraulic transmission and a generator were developed. A proportion-integral-differential （PID） control strategy was proposed to realize the rotor maximum power capture through adjusting the torque produced by variable displacement hydraulic pumps. The system modeling simulation on a 5MW floating wind turbine shows that when the wind speed changes below rated wind speed （11.4m/s）, the anti-torque on the rotor produced by hydraulic pumps approaches the optimal value as the new control strategy is implemented, so the optimal tip speed ratio （8.1） is got and the rotor maximum power is captured. Finally, the dynamic performance of the aerodynamic power captured by the rotor and the generator output power of the hydraulic transmission are analyzed and compared, as a result, the rate of power output is 80.2%.