Gholam Reza Moradi - Department of Electrical and Computer Engineering, University of Tehran, Tehran, Iran
Alireza Ramyar - Department of Electrical and Computer Engineering, University of Tehran, Tehran, Iran
Ehsan Afshari - Department of Electrical and Computer Engineering, University of Tehran, Tehran, Iran
Babak Farhangi - Department of Electrical and Computer Engineering, University of Tehran, Tehran, Iran

H5 is among the popular topologies used in the single phase photovoltaic systems due to its low leakage current and high efficiency. As the power capacity of photovoltaic systems is increasingly growing, grid standards should consider reactive power control for distributed solar generation units. In single-phase photovoltaic systems, this capability contributes to power quality of the grid. In this paper, the capability of the H5 topology for operating in power factors other than unity is analyzed in detail. The two conventional modulation methods proposed in earlier works, are evaluated according to the capability of reactive power injection, the leakage current issue, and efficiency of the topology. Moreover, a novel modulation method is proposed enabling the reactive power injection with less switching. In addition, switches’ stresses are reduced owing to the proposed modulation method. The advantages of the proposed method are validated using accurate MATLAB/SIMULINK simulations.

EMI; H5; grid-connected inverters; leakage current; modulation methods; photovoltaics; reactive power generation; residential power system; single phase converter; smart grid; transformer-less inverters