On using resetting integrator in current control loop for active power filter

Abstract

Current control loops is the key element in the control structure of active power filter systems. Among linear control techniques, deadbeat control has widely been accepted as a feasible current control technique as far the DSP implementation of APF is concerned. This control technique that uses high gains on the errors measured at one sample is 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 system dynamic response. Recently few papers have reported the results about the use of resetting integrators as filter in some electronic applications. This paper is an attempt to show possible application of resetting integrator as filter to current control for APF, where linear control methods have better frequency characteristics and current response than general deadbeat control. Simulation and experiment verify that these filters can be adopted to improve the performances of a current loop in APF.Index Terms--active power filter，current control technique, deadbeat control, noise rejection, proportional control, proportional differential control, resetting integrator, robustness, stability, triangular tracking PWM.