基于风机优化调控的风电场输出功率平滑控制策略研究

The conventional output power smoothing control strategies for wind farms include two kinds: indirect control methods by using energy storage systems and direct control methods through variable pitch and variable speed control of wind turbines. However, capacity configuration of the energy storage systems which can be very cost is always limited in reality. The variable pitch and variable speed control methods of wind turbines are less capable for smoothing the high power fluctuations while coming with the problems as may resulting in systems into unstable operation region. In order to eliminate aforementioned drawbacks, this project proposes a new output power smoothing control strategy for wind farms, which divides the wind turbines in a wind farm into two groups as control wind turbine group and power wind turbine group. The control wind turbine group is in charge of comprehensive regulating the power of the wind farm to achieve smoothing the output power. The power wind turbine group is responsible for the main power output of the wind farm by adopting maximum power point tracking control. Besides, an energy storage system with small capacity is applied to cooperate with the control wind turbine group to smooth power when the wind speed is widely fluctuating. The aims of the project are to study the basic principles of the proposed power smoothing control strategy, to explore the distribution method for the control wind turbine group and power wind turbine group with considering the wind farm topography, weather and so on, to choose the energy storage system type and the optimal capacity configuration, to propose the optimal control strategies for the control wind turbine group, power wind turbine group and energy storage system. This research will provide technical support for the wind farms to provide electric grids, which also have important scientific significance and academic value.

常规的风电场输出功率平滑控制方法主要有利用储能装置间接控制和利用风力机变速变桨距直接控制这两类。应用储能装置存在容量配置有限，成本高等问题，而采用风力机变速变桨距方法抑制大功率波动的能力较小，且易使系统进入不稳定区间。针对现有问题,本项目提出新型风电场输出功率平滑控制策略，将风电场风机分成控制风机群和功率风机群两类，控制风机群综合调节风电场输出功率，抑制输出功率波动，而功率风机群则实现风能最大利用。另外，风电场将配置小容量储能装置，在风速波动较大时接入配合控制风机群抑制功率波动。本项目旨在研究该新型风电场输出功率平滑方法的基本原理；探索基于风电场地形、气象等条件下控制风机群、功率风机群的分配方法；研究储能装置类型的选择及其容量的优化配置方案；提出风电场控制风机群、功率风机群及储能装置的最优控制策略。本项目研究将为风电场并网提供一定的技术支持，具有重要的科学意义和学术价值。

本项目提出了一种基于风机优化调控的新型风电场输出功率平滑控制策略，充分利用风电场各台风力机输出功率差异性的优势，将风电场风电机组分成控制风机群和功率风机群两部分，对控制风机群和功率风机群采用不同的控制策略，实现各自相应的功能，并配置小容量储能装置。且基于转子动能控制的功率平滑方法，控制功率风机输出较为平滑最大功率，以降低其转矩脉动，减小机械应力。将功率给定控制应用于控制风机，由控制风机和小容量储能装置共同负责风电场的总功率输出。且只有当控制风机的给定功率超过其最大输出功率时，才引入储能装置，以减少其充电和放电时间提高使用寿命。基于Matlab/Simulink建立了详细的风电场模型，在考虑较为准确的尾流效应基础上，对提出的功率平滑控制策略进行了验证。提出了一种基于分数阶阻抗模型的锂电池SOC估计方法，并建立实验平台实施了恒流放电实验和动态压力测试工况实验。实验数据分析表明，基于分数阶阻抗模型的FUKF算法能够快速准确地估计锂电池SOC，其误差维持在1%以内，为锂电池储能系统的控制策略选择提供有效保证。针对绕组三角形接法的异步电机，通过分析风力机特性，对其采用矢量控制方法使其模拟风力机运行，实验验证了其有效性。