强跟踪UKF算法在光伏系统MPPT中的应用

Application of the strong tracking Unscented Kalman filter algorithm in photovoltaic system maximum power point tracking

强跟踪UKF算法是采用Unscented策略逼近非线性分布且强跟踪系统突变的状态估计算法,该算法兼具强跟踪算法鲁棒性强、Unscented变换精度高、实现简单的优点。针对光伏系统在部分遮蔽情况下最大功率点误判问题,结合恒压法与强跟踪UKF算法,提出了一种新的光伏系统MPPT策略。采用恒压法快速定位最大功率点的电压范围;在该电压范围用尽量小步长的控制电压,以相应瞬时功率作为被估量,采用STUKF算法精确估算最大功率点,确定相应控制电压;保证光伏系统MPPT跟踪速度基础上,提高跟踪精度,通过状态跟踪判断状态突变,避免了误判问题。仿真和实验验证了所提策略的正确性、有效性。

Strong tracking Unscented Kalman filter algorithm is an estimation method of approximating nonlinear distribution by the Unscented strategy and tracking strongly system status mutation. The algorithm combines the advantage of strong tracking algorithm robustness, high accuracy of Unscented transform and simple realization. In allusion to the photovo｜taic system maximum power point misjudgment problem under partially shaded conditions, a new MPPT control strategy is proposed by combining fixed voltage method with strong tracking Unscented Kalman filter （STUKF） algorithm. The voltage range of the maximum power point is determined by the fixed voltage method. In this voltage range, the small-step control voltage is adopted, the instantaneous power is taken as the estimative value, the power maximum power point is accurately estimated by the strong tracking Unscented Kalman filer, and its corresponding control voltage is obtained. The MPPT tracking accuracy is improved on the basis of assuring the MPPT tracking speed. The mutation status of power is detected by tracking the state, and the MPPT misjudgment problem is avoided. The correctness and effectiveness of the strategy is verified by simulation and experiment.