I am finding it difficult to design a 50MW VSC PV inverter.

I am designing a 150 MW PV power plant. Where there will be three 50MW inverters and I am now designing the 50 MW inverter. In the system, I have PV array connected with a MPPT controller, the output of the MPPT controller goes to a boost converter dpoubling the voltage output. And, the output then connected to the DC link capacitor. The output of the capacitor is connected to the inverter. For acheiving 50 MW DC power I am using 500MW pv arrays 15 connected in series and 7468 connected in parallel. But I don't get more than 14 MW of power. I have tried changing the DC link capacitor value as well as boost converter inductor capacitor value but the PV dc power output is not increasing more than 14 MW . Can anyone help me with this problem?

Answer 1

[MULI]

Hi Prithwi,

I understand that you are facing an issue in obtaining the desired output power. You can try the below suggestions to identify the issue:

• Make sure all the series and parallel connections in your PV array are set up correctly to give rated output

Series Connections: Ensure all modules have similar current ratings.

Parallel Connections: Confirm each string has similar voltage levels

• Your MPPT controller might not be hitting the exact maximum power point. Try adjusting its settings like step size, petrubation frequency etc to make sure it’s fully optimized for your array.
• Test the PV array and MPPT controller in isolation (without the boost converter and DC link) to confirm that the MPPT can achieve close to the expected output power.
• The duty cycle of the boost converter should be tuned to achieve the desired voltage increase. For a significant voltage boost, ensure the duty cycle is within a range that allows efficient power transfer.
• You could also temporarily reduce the PV array size (in parallel connections) to see if a smaller, more manageable power level can reach the desired 50 MW.

You can refer to the below example which shows the design of a boost converter for controlling the power output of a solar photovoltaic (PV) system

https://www.mathworks.com/help/releases/R2022b/sps/ug/solar-pv-system-maximum-power-point-tracking-using-boost-converter.html