一种改进型扰动观察法光伏最大功率点跟踪的建模与仿真

An improved perturbation observation method photovoltaic maximum power point tracking modeling and simulation

针对传统扰动观察法在最大功率点存在的功率损耗、跟踪速度以及稳态精度方面的缺陷,提出了变步长扰动观察法结合拉格朗日插值法的复合控制策略,通过改变扰动步长快速定位到最大功率点附近,在该点附近取3个互异插值点代入插值多项式中,所得的插值函数与光伏电池的P-U特性曲线对应的函数相同,对插值函数二次求导得出最大功率点所对应的输出电压。在Matlab中搭建最大功率点跟踪(MPPT)电路的仿真模型,仿真结果表明:该MPPT复合控制方法可以加快控制器的响应速度、有效抑制震荡、快速定位最大功率点的位置。

In the traditional perturbation and observation method,there exist some problems of the steady-state power loss,tracking speed,and steady-accuracy near the maximum power point tracking(MPPT).A composite control method based on variable-step perturbation observation and Lagrange interpolation is proposed.By the change of the perturbation step size and the rapid positioning near the maximum power point,three interpolation points near this point are taken and plugged into the interpolation polynomial.The interpolation function obtained is the same as the corresponding function of the P-Ucharacteristic curve of the photovoltaic cell.Finally,the output corresponding to the maximum power point is obtained by the second derivative of the interpolation function.By building the circuit in the Matlab MPPT simulation model,the simulation results show that the MPPT composite control method can accelerate the response speed of the controller,effectively suppress the vibration,and quickly locate the position of the maximum power point.