A new modulation technique for reduced harmonic distortion of current in PV inverters

This paper deals with the modeling of a single-phase PV inverter using current control. Two control methods are described; the hysteresis band and the zero-tolerance control. A study for the optimization of the Total Harmonic Distortion (THD) of the output current and for the minimization of the switching losses is being conducted. A new modulation method is also presented, defined as mixed modulation, which is a combination of the unipolar and bipolar modulation. The mixed modulation is applied both to the hysteresis band and to the zero-tolerance control. It is proved, by simulation, that this method produces the best results, since it combines the advantages of the other two modulation methods. A comparison between the modulation methods is conducted, using as criteria the THD of the output current of the inverter and the efficiency of the inverters.