The influence of the converter current and voltage
control loop bandwidth on the damping ratio of the dominant
eigenvalue pairs is depicted in Fig. 7. The voltage control
loop bandwidth is related to the converter current control
loop bandwidth f by a division factor b which varies from 10
to 15. Again, it can be observed that the damping ratio
decreases with increase of the current loop control
bandwidth, but the damping ratio will be further reduced
with a higher voltage control loop bandwidth.