5 crucial facts you should be aware of when choosing PV inverters

Why an inexpensive inverter might call for an expensive lawyer

PV inverters are a source of electromagnetic interference (EMI) that has to be limited. Otherwise, it might interfere with the military, air traffic control, railroad, or FM-radio frequencies. If that happens, it could get you into severe legal trouble.

EMI occurs during the flow of electrons in many devices, including PV inverters. The level of EMI generated by PV inverters must be below a certain level for many important reasons since high levels of EMI can disrupt the functioning of many critical operations including air traffic control, military applications, and other communications.

EMI values 16x higher than legally allowed
Our testing of a competitor’s inverters revealed that, in many instances, the levels of EMI were far above the permissible limits of regulation EN 6100-6-3:2011. We found that peak values were measured at 65 dBμV/m, which is more than sixteen times above the allowable threshold . However, our competitor claims an unwarranted conformity, with all legal requirements and relevant technical standards, by placing a “CE” mark on their nameplates and product documentation.


Electromagnetic Interference (EMI)
How could this happen?
We believe that the reason the EMI levels are so high in our competitor’s products is due to undersized filters. In our view, due to our competitor’s passive cooling concept, undersized filters are used to generate less heat and therefore less power losses. If appropriate-sized filters were used in the inverters, the costs would increase. Our tests lead one to assume that our competitor has chosen to save costs and thereby create a potentially dangerous environment. 

In other words, it is not just one single incorrect component causing the high level of EMI, it is the overall design concept of their inverters that forces our competitor to build and sell inverters that cannot comply with existing laws. 

Possible consequences
Disturbing the radio frequencies of air traffic control, the military, or railroad communications is an unlawful act. In Germany, this might be a violation of §315 StGB (Gefährliche Eingriffe in den Bahn-, Schiffs- und Luftverkehr), which could result in a punishment of up to 10 years’ imprisonment.


Why Redesign of EMI is Not Effective