A new strategy for load side harmonic reduction using grid-connected photovoltaic inverters

The grid-connected photovoltaic (PV) inverters operate only a limited time interval at their nominal power. Therefore it is possible to incorporate their power conversion capacity for improving the power quality of the grid. The growth of nonlinear loads and increasing harmonics has led many researchers to suggest the use of PV inverters with harmonic compensation capability. However, the earlier methods do not usually consider the inverter current limitation and its main task, which is to inject active power to the grid. In this paper, by using the Discrete Fourier Transform (DFT) method and considering the free capacity of the inverter, a scaling factor is defined that adjusts harmonic levels to limit inverter current at the rated value. Due to selective harmonic calculation method, maximum power point tracker (MPPT) is not affected by the harmonic compensation and also by applying the proposed scaling factor, the inverter will not be at the risk of overload.