Harmonics play a vital role in affecting the performance of all electrical systems. Passive filters were used to suppress these harmonics, despite the associated problems such as parallel and series resonance. Recently, active power filters were introduced to overcome the drawbacks of passive filters. This paper proposes an improved control algorithm to suppress the harmonics introduced by variable nonlinear loads. The algorithm is applied on a hybrid power filter composed of an active filter in series with a passive filter. A comparative analysis of the proposed algorithm with two different conventional algorithms (d-q and p-q algorithms) is carried out for variable nonlinear loads. The presented algorithm is based on d-q transformation, and the injection of the 5th harmonic component in a proposed control circuit. The overall system is simulated, and extracted results were discussed concerning the values of the dc link voltage and the THD.