Predictive Control with Fixed Switching Frequency for Three-Level Boost and NPC Converters Interfaced PMSG Wind Turbine

A power conversion system based on a diode rectifier, three-level (3L) boost converter and 3L neutral-point clamped (NPC) inverter is a cost effective and reliable solution in contrast to the back-to-back connected NPC converter for the medium-voltage permanent magnet synchronous generator-based wind turbines. This paper investigates a novel predictive control scheme to operate the 3L boost converter and an NPC inverter with fixed switching frequency, high-speed tracking, and accurate locking in steady state. A dual decoupled control loop consisting of deadbeat current control and modulated model predictive current control has been developed for the 3L boost converter and NPC inverter, respectively. The controller for three-level boost converter performs dual functions such as neutral-point voltage control and inductor current control. The controller of NPC inverter regulates the grid currents in stationary frame for the simultaneous control of active and reactive powers.