Comparison of topologies of hybrid active power filter

Hybrid active power filters are used for reducing harmonics in the power system. This paper deals with different topologies of hybrid active power filter discussed along with their control. In a hybrid active power filter the active power filter is used to filter out higher order harmonics, while the lower order harmonics are filtered by the passive filters tuned for particular frequency. This combination reduces the cost and size of active power filter considerably; at the same time the problems associated with passive filter installed alone are also eliminated. With this study a comparison of different topologies of hybrid active power filter is presented on different indices such as THD, complexity and cost and topology- I has been proven to be superior. Here active power filter of HAPF is of voltage source inverter type with current control, the passive filters are tuned to fifth and seventh harmonic frequencies, the source taken is 3-phase, 3- wire type and a 3-phase diode rectifier with resistive load is considered as load. The simulation is done on MATLAB / Simulink-PSB.