Skip to main content

Global success for CE+T Power’s miniature inverter

In 2015, CE+T Power took up the challenge thrown down by Google and the Institute of Electrical and Electronics Engineers (IEEE) to create an inverter one-tenth the size of current models. Inverters convert the energy created by batteries and solar panels into a useable form by transforming direct current into alternating current. By making them smaller, Google and the IEEE hope to facilitate the penetration of renewable energy systems and other battery-operated applications.
  • July 2014: Google and the IEEE challenge companies to develop an inverter that is both powerful (2 kW) and small (40 cubic inches). This is the Little Box Challenge.
  • September 2014: CE+T Power takes on the challenge with the help of its partners, Sirris and ULg, and support from the Walloon Region.
  • February 2016: the inverter developed by CE+T Power has a power of 2 kW and measures less than 14 cubic inches; it wins the Challenge.


CE+T Power is a Belgian SME specialising in industrial inverters. Founded in the Liège area in 1934, it has specialised in power electronics since the 1960s. In the late 1980s it invented the modular inverter. Today it is present in Belgium as well as China, India, Luxembourg and the United States.

“Sirris developed an original strategy for determining the optimum geometry of the cooling system.”


Miniaturisation of cooling system

One of the main challenges in designing a miniature inverter is how to cool the electronic components effectively in a very small space – with little room for the cooling system or for air to circulate. The cooling system is vital for the proper operation of the device and for extending its service life.   

Computer-assisted optimisation

Drawing on its 15 years of expertise in thermal management, Sirris designed a cooling system adapted to the space available. To work out the optimum geometry, it used a dedicated strategy of computer-assisted optimisation, which enabled it to evaluate the performance of nine potential systems without having to actually build them. It then used its microfabrication expertise to produce and assemble the high-precision parts.

Smaller, more powerful and more reliable

The CE+T Power inverter was flown to the United States to have its performance compared against that of the 18 other shortlisted candidates. The results were announced in early 2016: an all-out victory for the solution developed by CE+T Power and its partners, which not only met the competition specifications but was three times more compact (13.77 cubic inches with the required power of 2 kW). Its service life also exceeded that of the other candidates – due in no small part to the quality of the cooling system developed by Sirris.