风电机组全风速段多目标发电优化控制

Multi-objective Optimization Control for Wind Energy Conversion System in Full Wind Speed Range

降低机械载荷、提高发电量以及平抑功率波动是风电系统的主要控制目标之一。研究发现,在持续性风速激励下,轴系扭振除特征频率振荡分量以外还存在与风速同频的宽频受迫扭振,而现有扭振抑制方法不仅无法应对受迫扭振,在不适当的参数下甚至会产生不利影响。文章聚焦于持续波动风速作用下风电机组的多目标发电优化控制,根据低频段削弱、同时特征频率增强的分频段轴系电气阻尼虚拟配置原则,基于小信号频域分析法揭示了扭振、最大功率点跟踪(maximum power point tracking,MPPT)和功率波动3个优化目标受控制器参数的影响规律。综合考虑了MPPT和功率波动对宽频扭振镇定的约束及3个目标的综合优化,针对全风速段不同工作模式分别设计控制器结构和参数,最后通过控制综合形成一套完整的控制策略。控制器硬件在环仿真表明所提控制策略可有效实现持续性风速激励下的多目标发电优化控制。

The main control objectives of wind energy conversion systems include reducing mechanical load,increasing power generation,and suppressing power fluctuations.It has been established that under continuous wind fluctuations,forced torsional vibrations exist on the drivetrain in a broad frequency band,which has nearly the same spectrum as wind fluctuations.Moreover,it has been found that existing active damping control schemes cannot cope with forced torsional vibration,which has adverse effects.This study focuses on the multi-objective generation optimization control of wind turbines under the action of continuously fluctuating wind speeds.Based on the virtual configuration principle of frequency division shafting electrical damping with reduced low-frequency bands and enhanced characteristic frequencies,the small signal frequency domain analysis method is used to reveal the influence of controller parameters on the three optimization objectives of torsional vibration,maximum power point tracking(MPPT),and power fluctuation.Considering the constraints of MPPT and power fluctuation on the stabilization of broadband torsional vibrations and the comprehensive optimization of the three aforementioned objectives,the controller structure and parameters are designed for different operating modes in the full wind speed range,and a complete set of control strategies is formed through control synthesis.The hardware-in-the-loop simulation of the controller confirms that the proposed control strategy can effectively achieve multi-objective power-generation optimization control under continuous wind fluctuations.