It is possible to note that the introduction of the feed-forward
action due to theCMcurrent estimator affects neither the number
and values of poles nor the number of zeros of the active filter
transfer function. As a matter of fact, the denominator remains
unchanged as well as the degree of the numerator. On the other
hand, the zeros displacement is influenced by the choice of the
CM current estimator parameters. A suitable selection of such
parameters makes it possible to perform a stronger attenuation
of VCM.