集中式太阳能逆变器快速MPPT方法

Quick MPPT method of centralized PV inverter

针对集中逆变式太阳能光伏电站最大功率点追踪(MPPT)问题,提出快速追踪方案。基于光伏(PV)电池单二极管5参数模型,建立考虑了失配参数的光伏阵列输出电压电流关系的数学模型,并通过实测电压、电流数据形成求解参数的非线性方程组;通过迭代算法获得各参数的值,进一步可以建立参数与实时温度和光照的对应数据库;运用拉格朗日乘子法对获得的U-I关系求解最大功率点,同时采用设置多初值的方法避免多峰导致的局部最优情况。最后,再通过外电路调节,可一步到位将电路运行点调整至最大功率点。快速MPPT方法求解最大功率点更直接,调节更迅速,对电路的干扰更小。

Aiming at maximum power point tracking(MPPT)problem of centralized inverter solar power station,a quick strategy was proposed.Based on the 5-parameter single-diode model of photovoltaic(PV)cell,the mathematical model of the relationship between the output voltage and output current of the PV array was established,which also took the mismatch parameter into account.In order to determine the real-time relationship between voltage and current,several sets of measured voltage and current data were obtained to form the nonlinear equations of the parameters to get their instant values.The Newton iterative algorithm was adopted to solve the equation sets.Furthermore,a database was established according to the corresponding relationship between parameters and environmental factors including temperature and illumination.Then Lagrange multiplier method was used to obtain the maximum power point.Finally,through the external circuit adjustment,the maximum power point was achieved by only one step.The proposed method to solve the MPPT is more straightforward,quicker,and less interferential.