For Direct Current (DC) bus voltage control, a method generates a q-axis reference current from a DC voltage error that includes a DC voltage input modified by a DC bus voltage in a closed outer loop. The method further generates a d-axis reference current from the DC voltage error, wherein the second-order harmonic in the d-axis reference current is delayed from that in q-axis reference current by 90 degrees. The method generates a q-axis current from the q-axis reference current. The method generates a d-axis current from the d-axis reference current. The second-order harmonic in d-axis current is offset from the second-order harmonic in q-axis current by 90 degrees. The method controls the DC bus voltage of a voltage control plant to mitigate a second-order harmonic in the DC bus voltage with the second-order harmonics in the q-axis current and the d-axis current.