原创 光伏电池电气性能的评测——光伏电池的总体效率的测量参数1

其它一些可以从PV电池直流I-V曲线中得出的数据表征了它的总体效率——将光能转换为电能的好快程度——可以用一些参数来定义，包括它的能量转换效率、最大功率性能和填充因数。最大功率点是最大电池电流和电压的乘积，这个位置的电池输出功率是最大的。

Other data that can be derived from the DC I-V plot of a PV cell characterize its overall efficiency—how well it transforms light into electricity—and can be defined by a number of parameters, including its energy conversion efficiency, its maximum power capability, and its fill factor. The maximum power point is the product of the maximum cell current and voltage where the power output of the cell is greatest.

填充因数[1]（FF）是将PV电池的I-V特性与理想电池I-V特性进行比较的一种方式。理想情况下，它应该等于1，但在实际的PV电池中，它一般是小于1的。它实际上等于太阳能电池产生的最大功率（P_MAX=I_MAXV_MAX）除以理想PV电池产生的功率。填充因数定义如下：

The fill factor (FF) is a way to compare a PV cell’s I‑V characteristics to those of an ideal cell. Ideally, it would have a value of one, but in practical PV cells, it is always less than one. It is essentially the maximum power produced by a solar cell (P_MAX=I_MAXV_MAX) divided by the power produced by an ideal PV cell. The fill factor is defined as:

FF = I_MAXV_MAX/(I_SCV_OC)

其中I_MAX=最大输出功率时的电流，V_MAX =最大输出功率时的电压，I_SC =短路电流，V_OC=开路电压。

where I_MAX = the current at the maximum power output, V_MAX = the voltage at the maximum power output, I_SC = the short-circuit current, and V_OC = the open-circuit voltage.

转换效率（h）是光伏电池最大输出功率（P_MAX）与输入功率（P_IN）的比值，即：

The conversion efficiency (h) is the ratio of the maximum power output (P_MAX) to the power input (P_IN) to the photovoltaic cell, or

h = P_MAX/P_IN

PV电池的I-V测量[2]可以在正偏（光照下）或反偏（黑暗中）两种情况下进行。正偏测量[3]是在PV电池照明受控的情况下进行的，光照能量表示电池的输入功率。用一段加载电压扫描电池，并测量电池产生的电流。一般情况下，加载到PV电池上的电压可以从0V到该电池的开路电压（V_OC）进行扫描。在0V下，电流应该等于短路电流（I_SC）。当电压为V_OC时，电流应该为零。在如图1所示的模型中，I_SC近似等于负载电流（I_L）。

I‑V measurements of a PV cell can be performed under forward-biased (in the light) or reverse-biased (in the dark) conditions. Forward bias measurements are performed under controlled illumination of the PV cell, with the light energy representing the input power to the cell. The cell is also swept through a range of applied voltages, and the resulting current from the cell is measured. Typically, the voltage applied to the PV cell might be swept from 0 V to the open-circuit voltage (V_OC) for that cell. At 0 V, the current is expected to equal the value of the short-circuit current (I_SC). When the voltage is set at V_OC, the current is expected to be zero. In the model of Fig. 1, I_SC is approximately equal to the load current (I_L).