Second-Order Harmonic Reduction Technique for Photovoltaic Power Conditioning Systems Using a Proportional-Resonant Controller

This paper proposes a second-order harmonic reduction technique using a proportional-resonant (PR) controller for a photovoltaic (PV) power conditioning system (PCS). In a grid-connected single-phase system, inverters create a second-order harmonic at twice the fundamental frequency. A ripple component unsettles the operating points of the PV array and deteriorates the operation of the maximum power point tracking (MPPT) technique. The second-order harmonic component in PV PCS is analyzed using an equivalent circuit of the DC/DC converter and the DC/AC inverter. A new feed-forward compensation technique using a PR controller for ripple reduction is proposed. The proposed algorithm is advantageous in that additional devices are not required and complex calculations are unnecessary. Therefore, this method is cost-effective and simple to implement. The proposed feed-forward compensation technique is verified by simulation and experimental results.