Dual-Side Selective Harmonic Elimination Technique for Voltage Source Converters Interfacing DC Microgrids and AC Networks

Voltage source converters (VSCs) are commonly employed to interface dc and ac networks in dc microgrid (dcMG) systems. However, when the dc-side current harmonics introduced by these VSCs interact with inherent dcMG system resonances, the dcMG system stability and power quality will deteriorate. To address this issue, this article proposes a cost-effective dual-side selective harmonic elimination pulse-width modulation (DSSHE-PWM) technique for two-level VSCs. The proposed DSSHE-PWM simultaneously eliminates harmonics introduced by the VSC in both the ac-side voltages and the dc-side current. To achieve this, first, the correlation between the VSC modulation and the dc-side current harmonics is investigated. Subsequently, the corresponding ac-side voltage harmonics that create the concerned dc-side current harmonics are identified. These voltage harmonics are then incorporated into an optimization problem to generate switching patterns for the VSC. The effectiveness of the proposed technique in improving the power quality and stabilizing the dcMG system is validated with both simulation and experimental results.