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建立通用而精确的太阳电池热模型对光伏系统的建模、输出功率与转换效率的损失分析至关重要. 基于复杂的太阳电池温度机理, 分别研究了太阳电池温度的稳态热模型(steady state thermal model, SSTM)和支持向量机(support vector machines, SVM) 方法建立的精确预测热模型. 首先, 基于空气温度、太阳辐射强度、风速3个最主要因素与太阳电池温度的近似线性关系, 在已有SSTM的基础上, 建立并校正了太阳电池的SSTM并采用差分进化算法提取模型的未知参数. 其次, 为提高SVM的模型预测精度, 采用粒子群优化(particle swarm optimization, PSO) 算法对SVM的核参数和惩罚因子进行动态寻优, 在确定输入/输出样本集并划分训练集和测试集的基础上, 建立了基于粒子群优化支持向量机(PSO-SVM)的太阳电池温度精确预测热模型. 最后, 搭建实验平台, 在实验操作过程中减弱空气湿度、太阳入射角和热迟滞效应等因素对太阳电池温度的耦合. 通过实验对比表明, 建立的预测热模型性能可靠、全面、简洁, 其参数寻优算法优于遗传算法和交叉校验法, 模型预测精度优于反向传播神经网络(back propagation neural network) 和SSTM.Establishing a general and precise solar cell temperature model is of crucial importance for photovoltaic system modeling, the loss analysis of output power, and conversion efficiency. According to the complex mechanism of solar cell temperature, in this paper we study the steady state thermal model (SSTM) of solar cell temperature and accurate prediction model of method of support vector machine (SVM). Firstly, based on the approximate linear relationship among air temperature, solar radiation intensity, wind speed and solar cell temperature, the polynomial model of solar cell temperature is established and the unknown parameters of the model are extracted with the improved differential evolution algorithm. Secondly, in order to improve the accuracy of SVM prediction model, the particle swarm optimization algorithm is adopted to optimize the parameters (including kernel parameter g and penalty factor C from the radial basis function kernel) of SVM. After the input/output sample set is determined and the training set and test set are classified, a prediction model of solar cell temperature based on particle swarm optimization support vector machine is established. Finally, experimental acquisition platform is built to reduce the influences of air humidity, solar incidence angle, and thermal hysteresis effects on PV cell temperature. Through contrasting experiments, it is shown that the established fitting of the SSTM is better than the models given in other literature, and the prediction model is reliable, comprehensive and simple. The selected parameter optimization algorithm is superior to genetic algorithm and cross-validation method established on the optimization performance, and the accuracy of prediction model is superior to the prediction performance of back propagation neural network and identified SSTM.
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Keywords:
- solar cell temperature /
- thermal model /
- support vector machines /
- particle swarm optimization







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