Chroma ATE Inc.

Chroma’s New Solar Array Simulation Power Supply Provides Dynamic MPPT Test of PV Inverter (May 23)

The photovoltaic array and inverter are the two major components built into a grid connected PV system. Their performance is critical as it determines the system’s return of investment. Since the installation location directly impacts the PV system’s long-term power generation, weather conditions and variables like available irradiance and temperature change needs to be taken into consideration in both design and production. Until now, technology is tending to create a running condition of actual weather within a particular period to test the DC generation of PV array and dynamic MPPT performance of PV inverter. In Europe, the latest test standard EN50530:2010 was published in May 13, 2010. Within that standard, a procedure was proposed for testing the overall efficiency and dynamic MPPT performance of grid connected PV, such as the intensity variation from 10% low luminance to 50% middle luminance or from 30% middle luminance to 100% high luminance.

Chroma’s newest solar array simulating DC power supply, 62150H-1000S, provides simulation of Voc (open circuit voltage) up to 1000V and Isc (short circuit current) up to 15A in a compact 3U high unit with maximum power up to 450kW/1000V/450A. Its design delivers a fast transient response simulation of the solar cell output I-V curve and applies it to the PV inverter for MPPT performance testing.

The advanced Dynamic MPPT Test function complies with Sandia & EN50530 test regulation and can be controlled via the graphical softpanel by selecting Sandia or EN50530 I-V mathematical expressions and test items. This function simulates the irradiation intensity and temperature change of the I-V curve under actual weather variations to test the PV inverter’s dynamic MPPT performance. The user can easily edit the execution time and temperature change time from low to high irradiation intensities by Dynamic I-V curve and also set the repetition cycle. The GUI will calculate the MPPT performance for analysis after running the test. A test data recording function is integrated into the software where users can edit and control the test parameters to be recorded such as voltage, current, power, watt and MPPT performance along with the sampling interval (1 - 10,000s) and total time length to facilitate the analysis and validation of the PV inverter.

In addition, the software can used in Table Mode to create and edit various I-V curves, save the I-V curve data to an Excel file, and import directly to the solar array simulation power supply. One standalone power supply is capable to storing up to 100 I-V curves. Each I-V curve can be assembled up to a maximum 128 points voltage and current array. This function enables the user to edit several I-V curves to test the tracking performance of the PV inverter under various conditions such as a shadow mask.

For more detailed information of Chroma’s Solar Array Simulation Power Supply and a free software download, please visit us at: