New generation microinverters for more energy efficiency

The Green PE demonstration pilot on smart houses aims to demonstrate the higher energy efficiency advanced power electronics solutions and intelligent control systems can achieve while also maximising energy savings and reducing costs.
As a part of this pilot, five photovoltaic test stations have been installed at the Physicum, a building of the Institute of Physics at the University of Tartu, one of Green PE project partners. Each test station consists of 12 Amerisolar solar cells of type AS-6P30 with a nominal power of about 270 W and provides a module efficiency up to 16.6%.
During the pilot, also the monitoring of the solar panels is important to ensure the panels are operating correctly and the system is generating as much as predicted. Therefore, also an uncertainty certified equipment measuring the outcome has been installed at the Physicum in addition to the inverter monitoring system.
In the second half of 2017, three test stations with silicon-based inverters were already online with a total solar energy production of 3.5 MWh. The current generation of smart microinverters installed at the Physicum is based on a combination of Silicon (Si) and Siliconcarbid (SiC) semiconductors:

  •  low-voltage Si MOSFETs on the input side
  •  high-voltage SiC schottky dodes for the rectifier
  •  a combination of Si and SiC MOSFETs in the grid side inverter

The next generation of microinverters will be installed and tested at the Physicum by the end of 2018. Based on the combination of Gallium nitride (GaN), Si and SiC semiconductors, the new microinverters open up the possibility to compare both – previous and next generation power electronics.

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Energy production example of two days ©Toomas Plank, University of Tartu

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Energy production by month ©Toomas Plank, University of Tartu