【摘要】 针对5 MW Spar式海上风力机在复杂海况下的多频段振动耦合问题，提出一种新型双位置低频非线性能量阱(nonlinear energy sink, NES)控制系统。在平台底部设计分数幂次刚度低频NES以抑制0.010 0～0.100 0 Hz低频振动，在机舱下部布置双稳态宽频NES以控制0.200 0～2.000 0 Hz中高频振动。建立风-浪-流耦合作用下Spar平台-塔架-机舱-双位置NES系统非线性动力学模型，采用复变量平均法和多尺度分析推导慢变动力学方程，并以此为基础提出了双位置NES参数优化方法。数值仿真表明：在额定工况下，双位置NES系统可使平台纵荡响应降低9.5%,纵摇响应降低15.3%,机舱加速度降低27.2%;在极端海况下仍保持稳定的控制效果，且展现出相对调谐质量阻尼器更宽的控制频带和更好的鲁棒性。更多还原

【Abstract】 Aiming at the multi-frequency vibration coupled problem of a 5 MW Spar-type offshore wind turbine under complex sea conditions, a novel dual-position low-frequency nonlinear energy sink(NES) control system was proposed. A fractional power stiffness low-frequency NES was designed at Spar platform bottom to suppress low-frequency vibrations of 0.010 0-0.100 0 Hz, and a bistable broadband NES was arranged beneath nacelle to control mid-to-high-frequency vibrations of 0.200 0-2.000 0 Hz. A nonlinear dynamic model for Spar platform-tower-nacelle-dual-position NES system under wind-wave-current coupled action was established. Using the complex variable averaging method and multi-scale analysis, slow-varying dynamic equations were derived. Then, a dual-position NES parametric optimization method was proposed. Numerical simulation showed that under rated working conditions, the dual-position NES system can reduce platform surge response by 9.5%, pitch response by 15.3% and nacelle acceleration by 27.2%, respectively; the system can maintain stable control effect even under extreme sea conditions, and exhibit a wider control bandwidth and better robustness compared to tuned mass dampers.更多还原