Generalised predictive control for a 12-bus network using a Neutral-Point Clamped voltage-source-converter UPFC

The paper presents the application of a UPFC to a case study of a 12-bus high power network. The UPFC shunt converter employs 8 3-level Neutral Point Clamped (NPC) voltage source converters (VSC) and 12 single-phase three-winding phase shifting transformers (PST), generating a 48-pulse output voltage. The 3-phase H-bridge series converter shares the same dc-link with the shunt one. The novel feature of this work lies in the use of a model-based generalised predictive current control law to the shunt converter for voltage and power flow control which has shown superior performance without additional filters compared to a P+I control scheme. In addition with the phase shift and switching angle control of each NPC-VSC output voltage, the topology offers improved harmonic performance and a zero-sequence blocking transformer is used for total triplen harmonics elimination.