Space Vector-Based Common-Mode Currents Reduction Method for H8 Inverter Topology in Low-Voltage DC Microgrid

This paper proposes a space vector-based common-mode (CM) currents reduction method for H8 inverter topology in low-voltage dc microgrid system. There are several power quality issues in dc microgrid about harmonics and CM electromagnetic interference (EMI) due to power electronicsbased converters operating at fast switching frequency. Generally, these issues are mainly related to the variation components in CM voltage causing CM leakage currents. Although many studies and solutions for CM voltages and currents reduction have been performed, some CM voltage variations and CM currents are still generated in the realistic implementation. This paper considers theses realistic effects and proposes the symmetrical space vector modulation (SVM) based CM currents reduction method for H8 inverter. The proposed method selects the voltage states having the same CM voltage level and combines these states for voltage modulation considering dead-time effects of H8 inverter. The proposed method is suitable for dc microgrid application because the number of CM voltage variations is completely limited to six times during a period of the space vector and it almost removes CM currents. The validity of the improved method for H8 inverter topology is verified with simulation results.