| Abstract |
The back-to-back converter has interesting properties. The controlled rectifier makes it
possible to simulate a purely resistive load. Further, the DC-link voltage regulation makes it
possible to reduce the DC-link capacitor to about 4 µF per kW nominal power. With this
capacitor size, however, the converter can not normally handle grid imbalance and voltage
distortion while simulating a resistive load. By using the load to regulate the DC-link voltage,
transferring power variations to the load, the reduced capacitor will not limit the capability to
handle distortion and imbalance. This strategy also enables the converter to continue
operation through power dropouts. By automatically using energy stored in the load inertia to
keep up the dc-link voltage, the converter can stay alive for several seconds, depending on the
load characteristic. |
