Optimized combined harmonic filtering system

This paper presents a thorough analysis of the operation for the combined filtering system consisting of a passive filter with diodes connected in parallel with the capacitors and a low-power inverter. The diodes limit the voltage across the capacitors and the inverter starts to work when disturbances occur in the three-phase network, sending back to the network the excess energy taken by all the capacitors from the network during these disturbances. The proposed combined filtering system has reduced size and cost as well as high efficiency. Laboratory experiments and simulation results proving the effectiveness of the solution are also presented.