太阳能工程师的任务之一是确定太阳能电池板系统的效率。确定太阳系效率的第一步是太阳能电池板系统技术的综述。PV面板系统由阵列的PV面板组成，其输出应用于转换面板DC输出到AC的逆变器。这些逆变器必须确保它们可以从连接的PV面板转换最大功率。最大PV面板功率取决于面板本身以及温度和太阳照射的环境因素。
为了连续获得PV面板的最大功率意味着，尽管环境影响，但您必须在其最大功率点（MPP）上运行。为实现这一点，与PV面板一起使用的逆变器采用最大功率点跟踪（MPPT），这是最佳太阳系效率的关键。因此，一种检查光伏面板逆变器效率的一种方法需要一种用于在所有环境条件下监控逆变器的MPPT的方法 - 即，用于温度和太阳照射变化，这是具有挑战性的。此外，您需要确保您的太阳能逆变器能够转换太阳能阵列的最大功率。
有三种方法可以测试光伏面板 - 变频器：
- 将阳光直接应用于连接到逆变器的PV面板
- 将光伏面板逆变器组合暴露于阳光的明亮光源。
- Apply the output from a PV simulator to the inverter.
MPPT算法是复杂的，并且难以晒上温度和辐照度条件的太阳能测试是困难，昂贵的，耗时的。各种太阳能模块的综合阳光下降几乎是不可能的，因为太阳能电池技术迅速变化。此外，您还必须提供监控变频器MPPT的手段。
One type of light source activated solar simulator uses a 100-W Xenon arc lamp with optimized optical system that delivers more than one AM1.5G sun irradiance over a 50 × 50 mm area. Standard optics minimize harmful ultraviolet radiation. Optional accessories include an electronic shutter to provide computer control for light soaking and timed irradiance. This approach also needs to provide a means for monitoring the inverter’s MPPT.
A PV simulator relies on the model of an ideal solar cell with a current source (I1）与二极管（D）的反平行（Fig. 1）。当电池暴露于光时，它会产生与太阳辐射线性变化的直流电。另外，与二极管（RP）另一个串联（rS）。
Photovoltaic (PV) panels have a nonlinear voltage-current characteristic based on the model inFig. 1。The I-V curve ranges from the short circuit current (ISC）在开路电压下为零电流为零电流（V.OC.）。At the knee of a normal I-V curve is the maximum power point, where the panel produces its maximum electrical power. The associated inverter must constantly adjust the load, seeking the specific point on the I-V curve that produces maximum DC power.
使用PV电池的简化模型，您可以生产PV电池的I-V（电流电压）曲线，其描述了在现有辐照度（光线水平）和温度下的能量转换能力(Fig. 2)。曲线表示具有恒定辐照度和细胞温度的恒定或“加载”的电流和电压的组合。图2.shows a typical I-V curve and power-voltage or P-V curve derived from the PV cell model. Pmax是最大功率点。IMP是电流，VMP是最大功率点处的电压。
光伏阵列模拟器有助于开发和验证逆变器最大功率点跟踪算法和电路。电力生产中的小增量对太阳能发电的盈利能力产生了巨大影响。PV阵列模拟器帮助工程师从逆变器中捕获尽可能多的能量，这提高了太阳能发电的经济性。
To perform an accurate test of solar array inverters, the output of a PV simulator must faithfully follow the I-V curve of a solar array. It must respond just as a solar array would to the changing load conditions imposed by the inverter under test. To evaluate how well a simulator can do this, you need to consider three parameters: output noise current, phase error between output voltage and current, and the MPP tracking accuracy.
There is essentially zero phase difference between the output voltage and output current of a solar panel or array, even when inverters use MPP tracking strategies that change the load very quickly. To accurately simulate a solar panel or array, therefore, it is important that the phase error of the simulator be less than 15 deg., even if the load is changing quickly.
Another important specification is the maximum power point dynamic tracking accuracy. This is a measure of how much a simulator will deviate from a programmed I-V curve under dynamic conditions.
随着逆变功率类的功率增加，测试阵列的大小变得无法管理。PV模拟器的示例是最近引入的关键N8937APV and 8957APV(Fig. 3)。
您可以在实验室或制造线上使用N8937 / 57APV光伏阵列（PV）模拟器，以模拟现实世界光伏阵列的输出特性。The N8937/57APV PV array simulators are single-output, programmable DC power sources that can quickly simulate I-V curve characteristics under different environmental conditions (temperature, irradiance, age, cell technology, and more), enabling engineers to quickly and comprehensively test their inverters.
这些PV阵列模拟器提供稳定的输出功率，内置电压和电流测量，以及自动输出电压，电流从500到1,500 V和10至30 A。自动化能力使得单位比传统的矩形输出电源更灵活它们扩展了电源曲线以提供更多电压和电流组合。
光伏模拟器不提供输出有关d to the MPPT. It puts out power of a known curve, which has a max power point, since every curve has a max power point. Since the user creates the curve and downloads it into the PV simulator, the user knows the max power point that the simulator applies to the inverter. The user also knows the power into the inverter. Measuring the power out of the inverter then allows the user to calculate efficiency. However, measuring the input power and the output power at the same time also gives this same efficiency, and that is what the power analyzer does.
Besides using the N8937/57APV units to simulate PV arrays, engineers can use them for other test and measurement tasks. They provide 15-kW autoranging, programmable DC power for design verification, and ATE applications that require just the right amount of performance at an affordable price. Engineers can easily configure multiple units in parallel to create a single power supply that offers more than 90 kW.
This PV array simulator allows you to:
- 开发和验证变频器峰值电源跟踪算法和电路的性能。
- Measure inverter power conversion efficiency over a variety of simulated conditions (varying temperature and irradiance).
- 验证变频器是否产生从低电平到高压极低电压的电网级功率。
- 执行资格测试 - 在暴露于不同的环境条件下或之后确认逆变器性能。
- Perform accelerated lifecycle tests.
- Perform certification tests.
