Recursive control for active power filters

A low power factor and an increased harmonic content are some of the negative effects of the nonlinear loads and power electronics converters. In order to mitigate these effects, active power filters with complex current loops together with appropriate current control strategies are proposed. In this paper a new method to generate the reference current using a recursive algorithm is presented. Due to a slow variation of the DC load current, it becomes possible to calculate the new reference from previous data. This current reference is then given in advance in order to be able to compensate the delay of the classical discrete algorithm control and inverter dead time. Experimental results obtained with and without the recursive control loop are presented.