基于功率前馈的变步长直接占空比扰动法的MPPT研究

The MPPT Research Based on Variable Step Size Direct Duty Ratio Perturbation Method for Power Feedforward

光伏发电是一种绿色环保技术,为了更好的研究外界环境对光伏电池输出功率的影响,该文建立了光伏电池在改变光强、温度参数下通用四参数工用模型,在此模型基础上,提出了一种基于功率前馈的变步长直接占空比扰动法的最大功率点追踪技术(Maximum Power Point Trace,MPPT)。首先根据光伏电池等效电路和数学模型建立温度、光强改变时电池的工用模型,以Buck电路的直接占空比数学模型为理论依据对现有的直接占空比扰动观察法做了改进,设计出一种基于功率前馈的变步长直接占空比扰动法算法。结合所建立的光伏电池模型,使用Matlab中的Simulink模块对其进行了特性仿真。仿真结果表明,改进后的变步长直接占空比扰动观察法具有追踪速度快的优点,并且能够在临近最大功率点的地方有效减少扰动观察法的功率振荡损失,提高了追踪的稳定性。

Photovoltaic power generation is a kind of green environmental protection technology.In this paper, In order to better study the influence of external environmet on the output power of photovoltaic cells,a general four parameter model for photovoltaic cells under varying light intensity and temperature parameters is established.On the basis of this model, a maximum power point tracking technique（MPPT）based on power feedforward with a direct duty ratio perturbation method is proposed.Above all, according to the equivalent circuit and mathematical model of the photovoltaic cell, the working model of the battery is established when the temperature and light intensity change.Based on the mathematical model of the direct duty cycle of the Buck circuit, the existing observation method of the direct duty cycle disturbance is improved, after which we designed variable step size direct duty cycle perturbation algorithm based on power feedforward.Combined with the founded photovoltaic cell model, we carry out the process of characteristic simulation by using the Simulink module of Matlab.The finding shows that the improved variable step size direct duty cycle perturbation observation method has the advantages of fast tracking speed over the original algorithm.In addition, the power oscillation loss of the disturbance observation method can be effectively reduced near the maximum power point, thus improving the stability of tracking.