Transformerless Hybrid Power Filter Based on a Six-Switch Two-Leg Inverter for Improved Harmonic Compensation Performance



This paper proposes a transformerless HPF based on a new six-switch two-leg inverter with an enhanced harmonic compensation capability. Aside from presenting a reduced number of switches when compared with dual topologies, the proposed solution is capable of providing fully compensation even for loads with high harmonic content. Experimental results are presented for an HPF inverter prototype in order to demonstrate that the harmonic compensation performance.













Shunt passive filters, consisting of tuned LC filters and high pass filters, have been traditionally used as a simple and low cost solution to compensate current harmonics. Nevertheless, their performance strongly depends on the grid impedance and can possibly cause the unwanted parallel resonance phenomena with the grid. In the last decades, the increasing reliability of power semiconductor devices has motivated the development of power electronics solutions to the problem of harmonic circulation into the grid.



This project has proposed a transformer less HPF topology based on a novel SSTL inverter. The proposed inverter, which is divided in two units, is connected in series with two passive LC filters tuned in different harmonic frequencies of interest, aiming an improvement in the harmonic compensation performance with a reduced number of switches when compared with other dual topologies. A complete analysis of both inverter and passive filters, including the guidelines necessary to design the HPF, was presented. The control algorithm of the proposed system improves the performance of both passive filters through feedback and feedforward compensations and also controls the dc-link voltage. Experimental tests were carried out, including the individual response of each inverter unit and the overall response of the proposed system, proving its feasibility.






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Leonardo R. Limongi, Luis R. da Silva Filho, Luiz G. B. Genu, Fabricio Bradaschia, Member, IEEE, and Marcelo C. Cavalcanti, “Transformerless Hybrid Power Filter Based on a Six-Switch Two-Leg Inverter for Improved Harmonic Compensation Performance”, IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 62, NO. 1, JANUARY 2015