可变偏心距风力机模态特性分析

Modal analysis of variable eccentricity wind turbine

在水平轴风力机的结构基础上,文章提出了一种具有风轮侧偏功率调节功能的可变偏心距风力机。通过对整机进行模态分析及风洞测试,验证了该风力机在不同来流风速下运行的稳定性。模态分析结果显示:可变偏心距风力机前6阶固有频率均处于共振带之外;摆振为可变偏心距风力机整机的主要振动形式;来流风速对风力机的振动频率影响较小,在不同偏心距工况下,随着来流风速的增大,1阶动频均呈减小趋势,最大降幅为0.14%;风轮转速对风力机的振动频率影响较大,随着转速的升高,风力机的动频会显著升高,当风轮转速为180 r/min时,1阶动频较额定转速工况(450 r/min)相差24%;当风轮转速达到630 r/min时,1阶动频较额定转速工况相差14%;通过增大偏心距可实现对输出功率的有效控制,当来流风速为16 m/s时,右偏100 mm工况下的输出功率为未偏心工况的64%。

Based on horizontal axis wind turbine,a variable eccentric distance wind turbine with rotor side-bias power regulation is designed,and the stability of operating at different inflow wind speed is verified by modal analysis of the whole machine and wind tunnel testing.The results show that the first six natural frequencies of variable eccentricity wind turbine are outside the resonance zone.Swinging vibration is the main vibration form of variable eccentric distance wind turbine.The inflow wind has less effect on the vibration frequency of the wind turbine,and the first order frequency of different eccentric distance operating conditions decreases with the increase of the inflow wind speed,the maximum decrease is only 0.14%.Wind wheel speed has a greater impact on the vibration frequency of the wind turbine,with the increase of the speed,the frequency of the wind turbine will be significantly increased,when the wind turbine speed is 180 r/min,the first-order frequency is lower than the rated speed of 450 r/min about 24%.When the rotor speed reaches 630 r/min,the first-order frequency is greater 14%than the rated speed of 450 r/min.The output power can be well controlled by increasing the eccentric distance.When inflow wind speed is 16 m/s,the output power under the condition of 100 mm right deviations is lower 36%than under the condition of no eccentricity.