短路电流结合扰动观察法在光伏发电最大功率点跟踪控制中的应用

Short-current Combined With Perturbation and Observation Maximum-power-point Tracking Method for Photovoltaic Power Systems

光伏电池输出功率随外部环境和负载的变化而变化,为充分发挥光伏器件的效能,需采用最大功率点跟踪电路。对于最大功率点跟踪电路的控制已经提出了许多方法,其中短路电流法和扰动观察法因其具有简单有效的优点而得到广泛应用。针对短路电流法的缺点,该文提出一种新的在线短路电流控制方法。该方法在不干扰系统正常工作的情况下,能迅速感知外部环境变化,但该方法效率不高。为充分发挥光伏电池的效能,在线短路电流控制方法的基础上再引入扰动观察法。该文扰动观察法的扰动步长针对最大功率点处稳态特性进行优化,优化后,扰动观察法可有效消除光伏器件输出功率在最大功率点的振荡现象,从而提高系统效率。仿真和实验研究证明,该方法可以快速跟踪外部环境变化,并消除系统在最大功率点的振荡现象。

The output power of PV module varies with module temperature, solar insolation and loads, so it is necessary to track MPP of the PV array all the time. In past years, many MPP control algorithms were presented to draw maximum power from the solar array. A novel online short circuit current method is presented. This method can track MPP changes rapidly without disturbing PV system. On the basis of this method, P＆O（perturbation and observation） method with optimized perturbation step was proposed to reduce the power oscillation around MPP. Simulations and experimental results show that the PV generation system has good steady state and transient characteristics with the proposed MPPT control method.