Real-time algorithms for active power measurements on PWM-based electric drives

The paper deals with two algorithms for active power real-time measurements on PWM-based electrical drives. The first one is an off-line algorithm that reduces the mean power truncation error by means of the signal period estimation. The residual error is further reduced through a proper window obtained by convolving one or more triangular windows. The second one is an on-line algorithm that selects the dc-component of the instantaneous power by means of a low-pass IIR digital filter. Numerical results of the metrological characterization of such algorithms, aimed to suggest criteria for their optimized use, are presented. Moreover, the proposed algorithms are applied to signals probed by a measurement station on an actual PWM-based electrical drive. The experimental results confirm the conclusions attained through the numerical simulation and, moreover, are in perfect agreement with those obtained through a well acclaimed algorithm