基于动态阻抗匹配和两步模型预测控制的最大功率点跟踪算法

An Improved MPPT for PV System Based on Dynamic Impedance Matching and Model Predictive Control

为提高光伏阵列的能量利用率,提出了一种基于动态阻抗匹配(DIM)和两步模型预测控制(MPC)的最大功率点跟踪(MPPT)算法,首先建立光伏状态空间方程,计算当前时刻光伏系统动态阻抗并预测下一时刻外部阻抗,然后定义成本函数构建两步模型预测控制器,预测开关管状态控制DC/DC电路内部阻抗接近外部阻抗,从而实现光伏发电系统快速和稳定地输出最大功率,并通过Matlab/Simulink软件建立仿真模型进行验证。结果表明,该算法可行、有效,且大幅提高了光伏系统最大功率跟踪的快速性和稳定性。

To raise the energy utilization ratio of PV arrays, this paper proposes a novel maximum power point tracking （MPPT） approach which is based on dynamic impedance matching （DIM） and model predictive control algorithm. Firstly, DIM is used to predict the external impedance of the system at the next moment, offering the model predictive controller a reference value and change trend. Then the model predictive controller calculates the internal impedance of PV arrays according to the state space equations of the boost circuit. A cost function is defined to predict the state of switch tube in a DC/DC circuit and force the external impedance to approach the internal impedance. In this way, the PV generation system is able to track the maximum power point both rapidly and steadily. Simulation model is verified by Matlab/ Simulink software. The results show that the proposed method is feasible and effective; furthermore, the rapidity and stability of MPPT is improved greatly.