Tip of the day
Measuring efficiency of power electronics systems which are specified >99.3%? Here are my views.
There is an increasing trend to ask suppliers to measure efficiency at plant. It is not an easy task. There are number of elements in the system which are in cascade with different accuracies.
Measuring instruments must be suitable for non-sinusoidal / distorted waveforms. Check if instruments measure true RMS or extrapolated RMS.
Often accuracy of transducers, CTs, PTs, etc.is not constant and it depends upon load.
Measured samples must be synchronised with same time stamp.
If test lasts for longer duration, radiation losses and temperatures depend upon the difference in hot body temperature and medium which takes away heat.
The so-called simple input output method to measure efficiency is very complex in reality.
Unless thorough homework is done, one can get astonishing number, efficiency even better than 100% due to accumulated errors.
I would say carry out design review carefully and concentrate more on factory acceptance tests which can be carried out in controlled environment. Try to determine losses and estimate efficiency.
Good luck to those who measure efficiency at plants.
Maestro Emanuel, My efforts are to make people reliise not to spend time on unrealistic measurements. Often industry people are misguided.
Projektleiter Elektrizit?tsversorgung at Regionalwerke AG Baden
1 个月Yes, measured 101% efficiency +/-3% considering all the measurement errors once... Client wished to perform the measurement although we told him exactly what you wrote.
Vice President at ABB
2 个月Dear Shripad a very good practical explanation for a layman and technicians on the field and also it gives guidance where to concentrate for arriving at real practical efficiency! Thanks …!!!