A large number of renewable energy generation systems have been integrated into the electrical power systems through grid-connected inverters. To prevent shoot-through of inverter arms

the dead time needs to be applied

which introduces irrepressible dead-time low-order harmonics. In addition

due to the frequency coupling effect caused by control characteristics of the inverters

inherent harmonics can generate additional harmonic components. However

existing studies have neglected frequency coupling effects in dead-time harmonic modeling. Therefore

this paper first analyzes the mechanism of asymmetric frequency coupling effects and dead-time effects. Then the transmission process of dead-time harmonic voltages in the outer loop

inner loop

phase-locked loop

etc.

of grid-connected inverters are analyzed to establish a model of dead-time coupling harmonic sources for grid-connected inverters. By using both time-domain and hardware-in-the-loop simulation platforms

comparisons have been conducted with models established in other literature

which validate the proposed model. Finally

the effects of different control parameters and operating parameters on the model are considered

and the characteristics of the model under different conditions are analyzed.