With the continuous increase of grid-connected PV systems

the inter-harmonic problem due to the system is becoming more and more serious. Under the voltage background inter-harmonic

the inter-harmonic emission characteristics of grid-connected PV system becomes more complicated and is affected by the phase-locked loop（PLL）. For this purpose

the conversion relationship between the dynamic phasor in the dq coordinate and sequence component dynamic phasor is derived firstly

and the dynamic phasor of sequence components（DPSCs）model of the PLL is obtained. Then

on the basis of the model

the output of the PLL under the voltage background inter-harmonic and its influence on the modules in the control system are analyzed. After that

the inter-harmonic emission characteristics of grid-connected PV systemsare compared and analyzed in the case of ideal output of the PLL and of considering the dynamic condition of the PLL.Finally

a simulation model is set up

the simulation and theoretical analysis results are compared and the correctness of theoretical analysis is verified. Under voltage background inter-harmonic

the dynamics of the PLL will cause the coupling between the inter-harmonic components in the control variables

which in turn affects the amplitude of inter-harmonic currents emitted by grid-connected PV systems.