On using linear periodically resetting filter in current control loop for active power filter
Among linear control techniques, deadbeat control has been widely accepted as a feasible current control technique as far as the digital signal processor (DSP) implementation of active power filter (APF) is concerned. This control technique uses high gain on the error measured at one sample, to control the error ideally to zero by the next sample. The high gain makes the control very sensitive to any error or noise in the measurements, which is always there in electrical systems. Especially, the periodic noise in parallel implementation of an inverter or APF demands a higher order filter at the current transducer output, which affects the dynamic response of the system. Recently, few papers have reported the results about the use of linear periodically resetting integrators (LPRI) as filter in some electronic applications. This paper is an attempt to generalize the idea of LPRI and here we introduce the notion of linear periodically resetting filter (LPRF). The frequency characteristics of an LPRF are analyzed. Possible application of these filters in current control is studied. It is shown that these filters can be adopted to improve the performances of a current loop in APF.
deadbeat control active power filter (apf) linear periodically resetting integrator (lpri) linear periodically resetting filter (lprf)