Multiple Supplies Simulate Multiple Solar Arrays
Commercial solar inverters typically operate in the range of 30-1MW , with a solar array DC input voltage of up to 1500 VDC and produce three-phase AC power. At these power levels, it’s not practical to use a single array input. Instead, commercial inverters have multiple maximum power point tracking (MPPT) inputs that are summed at the DC/DC level before feeding into the DC/AC inverter. To test this type of inverter, you would use several autoranging power supplies, one for each input, as shown in the figure below.
EA Elektro-Automatik’s programmable supplies are rated as low as 1 kW per channel to as high as 2 MW per supply. The maximum output voltage is 2,000 VDC, and there no limit on how many supplies that you can use for this application. In addition, you can program each DC supply independently to simulate different irradiance profiles. For instance, on one inverter input, you can simulate a solar array in full sun, while on another input, you can simulate a solar panel that is partially or completely shaded.