Double frame control and power compensation for power converters connected to weak networks with disturbances

CERN is studying the implementation of high power active front ends, implying the operation of a voltage source inverters connected to a grid that can be considered as weak when compared to the converter nominal power. Proper synchronisation is a key point for current control stability. The handling of networks with asymmetric disturbances implies the accurate handling of the second harmonic component appearing under unbalanced networks by the proper decoupling of the positive and negative sequence of the network voltages and currents. The use of a double frame controller allow the full control of phase current symmetry or the compensation instantaneous active power oscillation.