absorbed by the converter and transferred to the ac system. The analysis of the
three-phase inverter is similar to that of the single-phase case.
The dc current must be in the direction shown because of the SCRs in the
bridge. For power to be absorbed by the bridge and transferred to the ac system,
the bridge output voltage must be negative. Equation (4-47) applies, so a delay
angle larger than 90 results in a negative bridge output voltage.