Solar Inverters
> Home
> Products
> Downloads and Videos
> Service
> News
> News Archive

Follow us:

Danfoss on Facebook Danfoss on Twitter Danfoss on LinkedIn Danfoss on YouTube
Danfoss Logo

Getting the Size Right

25 November 2010
The first of a series of articles on how to fit inverters and PV modules.

Optimal inverter sizing for PV power plants

Establishing the correct ratio between PV module power capacity and inverter power capacity is one of the key criteria for optimised PV power plant design. Under-sizing the inverter can lead to frequent “de-rating” of the PV power plant where, for example, the inverter moves the operating point away from MPP. This results in less PV power plant yield than possible. On the other hand, over-sizing the inverter leads to unnecessary costs.
Understanding the core criteria

During ratio selection, the following factors need to be taken into consideration:
• Irradiation
• Module temperature
• Orientation of the PV panel
• Tilt degree of the PV panel

For example, a plant sited in Central Europe that generates power using high-efficiency inverters should not exceed a layout factor of 1.12 (kWp/kWac), as given by Dr Bruno Burger, Fraunhofer ISE. However, if the orientation and inclination of the modules is not optimal, values can deviate.