Impact of CL and LCL low pass output filters on high order harmonics of single stage photovoltaic microinverter

Abstract

The new topology of photovoltaic microinverter based two-switch DC-DC flyback converters has been investigated [1]. The microinverter is characterized by the high performance and simple design. The effect of CL and LCL low microinverter have been investigated. The effect of flyback transformer parameters and effect of parameters of switch transistors on the microinverter efficiency have been investigated for both low pass filters. The results were found for the cases when CL and LCL output low pass filters were applied. The results show that the toral harmonics distortion THD of microinverter can reach 3.63% if the low pass filters and parameters of the flyback transformer and MOSFET transistors of switches are chosen correctly. The obtained results show that the THD of the investigated photovoltaic microinverter based on the LCL output low pass filter is lower as compared to the case when the LC output low pass filter is employed. The THD of microinverter with both output low pass filters is less than 5% respect the requirement of IEEE 1574-2014. Nevertheless, in the case when the LCL output low pass filter is used the THD decreases by 1% compared to the CL low pass filter.