Simplified control strategy for hybrid active filters

Nowadays, hybrid filtering is an important alternative to improve line performance when supplying high-power nonlinear loads. This paper presents a simple and low cost control strategy for hybrid filter as an alternative to other more complex algorithms, in some specific applications. The proposed control strategy is recommended for a utility interface with three-phase diode bridge rectifier front-end due to its high displacement power factor. It has been tested by simulations (both steady-state and transient analysis) and by experimental verification, where good results are obtained. It can be seen that using this control strategy, acceptable harmonic levels according to IEEE-519 standard are obtained. Also a different connection of the passive filter is experimentally verified, allowing the reduction of passive filter capacitors.