A voltage source converter (VSC) will generate low-order harmonics under unbalanced three-phase voltage causing harmonic pollution to power grids. With the wide application of VSCs in power systems

the harmonic pollution must be eliminated and given more attention by finding effective solutions. Based on dynamic phasors and symmetrical components

the sequence dynamic phasor is deduced and its characteristics are analyzed. The time domain VSC model containing a description of switching function is transformed into a dynamic phasor model. By setting the sequence dynamic phasors of AC current and DC voltage as the state variables

a harmonic analysis model in the state space based on the sequence dynamic phasors of VSC is developed. The model considers both the dynamic performance of power electronic devices and the interaction between AC and DC sides thus revealing the mechanism of how VSC generates harmonics. Based on the model

the harmonics generated by VSC can be calculated analytically. A harmonic elimination strategy with an unbalanced modulation to compensate the negative sequence voltage is proposed. Simulation results under various unbalanced conditions verify the correctness of the model and the effectiveness of the elimination strategy.