Patent ID: 7930119

Claim:
A method for harmonic analysis of an AC voltage signal having a fundamental frequency f 0 and harmonic content, comprising the steps of: defining a natural number n which indicates that the AC voltage signal is to be analyzed up to an n th harmonic of the fundamental frequency f 0 , computing from the fundamental frequency f 0 a first sampling frequency f=2nf 0 , multiplying the first sampling frequency f with a natural number m to obtain a second sampling frequency f sampling =mf=m2nf 0 which is higher than the first sampling frequency f, sampling the input AC voltage signal with the second sampling frequency f sampling to obtain a sequence of first sampling values, selecting from the sequence of first sampling values a second sampling value that is proximate to a zero-crossing of the AC voltage signal, performing the harmonic analysis of the AC voltage signal by using the second sampling value and in addition only each m th sampling value in the sequence of first sampling values before and after the second sampling value, and determining the harmonic content of the AC voltage signal.