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基于BP神经网络的风速估计与MPPT联合优化方法

A Joint Optimization Method for Wind Speed Estimation and MPPT Based on BP Neural Network

  • 摘要: 针对大型风电机组风速测量不准、MPPT控制动态响应差的问题,本文提出一种基于BP神经网络的风速估计与MPPT联合优化方法。首先,引入改进粒子群优化(IPSO)算法优化BP神经网络的初始权值与阈值,构建IPSO-BP风速估计模型,基于风轮转速与功率等易测参数实现等效有效风速的高精度在线估计(RMSE为0.16?m/s,延迟小于0.01?s)。其次,将估计风速用于生成最优转速参考轨迹,设计基于神经网络与误差符号鲁棒积分(NN/RISE)的MPPT控制器,其中IPSO-BP提供高质量前馈,在线神经网络补偿剩余未建模动态,RISE项抑制逼近误差与外部扰动。通过Lyapunov理论严格证明了闭环系统的渐近稳定性。仿真结果表明:所提方法在低风速湍流工况下,平均风能利用系数提高至0.476,转速跟踪误差较传统最优转矩控制降低72.4%,低速轴转矩损伤等效载荷降低35%,在参数摄动和突发阵风下表现出优异的鲁棒性。

     

    Abstract: To address the problems of inaccurate wind speed measurement and poor dynamic response of maximum power point tracking (MPPT) control in large-scale wind turbines, this paper proposes a joint optimization method for wind speed estimation and MPPT based on a back-propagation (BP) neural network. First, an improved particle swarm optimization (IPSO) algorithm is introduced to optimize the initial weights and thresholds of the BP neural network, constructing an IPSO-BP wind speed estimation model. Based on easily measurable parameters such as rotor speed and power, high-precision online estimation of the equivalent effective wind speed is achieved, with a root-mean-square error of 0.16?m/s and a latency below 0.01?s. Second, the estimated wind speed is used to generate the optimal rotor speed reference trajectory, and an MPPT controller is designed based on a neural network and robust integral of the sign of the error (NN/RISE) scheme. In this controller, the IPSO-BP model provides high-quality feedforward action, an online neural network compensates for residual unmodeled dynamics, and the RISE term suppresses approximation errors and external disturbances. The asymptotic stability of the closed-loop system is rigorously proved through Lyapunov theory. Simulation results demonstrate that under low-wind-speed turbulent conditions, the proposed method increases the average power coefficient to 0.476, reduces the rotor speed tracking error by 72.4% compared with the conventional optimal torque control, and lowers the low-speed shaft torque damage equivalent load by 35%. Moreover, it exhibits excellent robustness against parameter perturbations and sudden wind gusts.

     

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