共查询到19条相似文献,搜索用时 171 毫秒
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基于功率二次微分的光伏系统改进MPPT算法研究 总被引:1,自引:0,他引:1
提出了一种基于功率二次微分的改进最大功率点跟踪(MPPT)算法(简称PQD-MPPT算法)。算法在系统启动时采用恒定占空比启动,并给出了恒定占空比的求解公式,提出了根据功率变化量来调整跟踪步长的方法,当功率变化较大时,采用自适应大步长以使系统快速跟踪到最大功率点附近,反之较小时,根据功率对占空比的二次微分值的正负进一步划分跟踪区域:即当功率二次微分值为正时,采用固定大步长以使系统快速跟踪到最大功率点附近;当功率二次微分值为负时,采用自适应小步长以使系统能够稳定工作在最大功率点处。实验结果表明,与现有变步长MPPT算法相比,该算法具有良好的跟踪性能 相似文献
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针对强背景噪声下轴承微弱复合故障特征提取困难的问题,提出一种基于自适应变分模态分解(AVMD)和优化的Wasserstein距离指标(WDK)的风电齿轮箱轴承复合故障诊断方法。首先,引入自适应学习粒子群优化算法(ALPSO),以平均包络熵作为ALPSO的适应度函数来搜索变分模态分解的最佳影响参数,从而构造AVMD;其次,结合Wasserstein距离(WD)和峭度优点,提出WDK指标筛选有效模态分量,并对筛选的有效模态分量进行重构;然后,通过对重构信号进行包络谱分析实现轴承复合故障的诊断;最后,将所提AVMD-WDK方法应用于某风场2 MW风电齿轮箱轴承振动信号的故障诊断。结果表明,该方法能有效提取轴承的微弱故障特征,实现轴承复合故障的精确诊断。 相似文献
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双馈感应风力发电机的无源性控制方法研究 总被引:1,自引:0,他引:1
基于双馈感应风力发电机Euler-Lagrange系统模型,设计了本质上是非线性反馈的无源性控制(PBC)策略,实现了负载转矩时变未知情形下磁链、转速的渐近跟踪控制.针对实际运行时风力发电机参数具有不确定性的问题,将PBC方法与自适应控制相结合,不仅可实现电机参数摄动时期望电流轨迹的准确跟踪,并可有效抑制由电阻、电感变化引起的跟踪误差.该方法从能量角度分析风力发电控制系统,确定不必抵消的"无功力",设计全局定义的控制律,具有形式简单、无奇异点、鲁棒性好等特点.基于dSPACE 的实验结果证明了该控制策略的有效性. 相似文献
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A novel maximum power point tracking algorithm for small wind turbines is proposed. The solution presented here is an adaptive intelligent algorithm that uses a new advanced perturb and observe method to search for the optimum relationship of the system for tracking the maximum power point even under variable wind conditions. The validity of the proposed algorithm is analysed and the design procedure is presented. Its main virtue resides in its capability to adapt to changes in the turbine and in the surrounding environment, even under variable wind conditions, improving the efficiency of the system. The experimental results confirm the validity of the proposed algorithm. 相似文献
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In this paper, the power factor of a grid-connected photovoltaic inverter is controlled using the input output Feedback Linearization Control (FLC) technique. This technique transforms the nonlinear state model of the inverter in the d–q reference frame into two equivalent linear subsystems, and then applies a pole placement linear control loops on this subsystem in order to separately control the grid power factor and the dc link voltage of the inverter. Maximum Power Point Tracker (MPPT) that allows extraction of maximum available power from the photovoltaic (PV) array has been included. This MPPT is based on variable step size incremental conductance method. Compared with conventional fixed step size method, the variable step MPPT improves the speed and the accuracy of the tracking. 相似文献
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This paper addresses the development of new variable step size fuzzy based MPPT controller. In this study, the fuzzy logic approach is firstly used to auto-scale the variable step size of the Incremental Conductance (IC) MPPT controller. Secondly, the proposed variable step size fuzzy based MPPT controller is used to track the output power of the PEM fuel cell system composed of 7 kW fuel cell supplying a 50Ω resistive load via a DC-DC boost converter controlled using the proposed MPPT. The proposed variable step size fuzzy-based MPPT controller is compared to the conventional fixed step size IC, the variable step size IC and the fuzzy scaled variable step size IC MPPTs using the implemented Matlab/Simulink PEM Fuel Cell power system model. Comparative simulation results between the four studied MPPTs show better performances for the proposed fuzzy based variable step size MPPT in term of: response time reduction between 3.6% and 82.35%; overshoot reduction between 34.55% and 100%; and ripple reduction between 70.93% and 100%, improving as consequence the fuel cell lifetime affected by high current ripple. 相似文献
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A market‐oriented wind power dispatch strategy using adaptive price thresholds and battery energy storage
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In this paper, an adaptive dispatch strategy is presented to maximize the revenue for grid‐tied wind power plant coupled with a battery energy storage system (BESS). The proposed idea is mainly based on time‐varying market‐price thresholds, which are varied according to the proposed algorithm in an adaptive manner. The variable nature of wind power and market price signals leads to the idea of storing energy at low price periods and consequently selling it at high prices. In fact, the wind farm operators can take advantage of the price variability to earn additional income and to maximize the operational profit based on the choice of best price thresholds at each instant of time. This research study proposes an efficient strategy for intermittent power dispatch along with the optimal operation of a BESS in the presence of physical limits and constraints. The strategy is tested and validated with different BESSs, and the percentage improvement of income is calculated. The simulation results, based on actual wind farm and market‐price data, depict the proficiency of the proposed methodology over standard linear programming methods. 相似文献