Fixed point implementation of IIR filters using delta operator applied to distributed power generation systems

Signal processing algorithms like IIR filters applied to distributed power generation system must be programmed in fixed-point in the most of cases. This arithmetic causes errors due to the quantification. In z-domain implementations, for high sampling frequencies, poles very close to the unit circle can move to the unit circle bringing about an unstable behavior. Nevertheless, IIR filters implementations based on delta operator reach higher performance when the sampling time is small due to the stability region become similar to continuous time-domain. This operator permits to reduce quantification effects of the coefficients, to use smaller word length, to increase the efficiency and to reduce the resources consumed. In this paper, a study of IIR filter quantification and delta operator is carried out. As example, fixed-point implementation of second order generalized integrators (SOGIs) is realized, whose results show the advantages of using delta operator.