Multiobjective Predictive Control for Three-Level NPC Grid Connected Converter
Abstract
In recent years with higher levels of wind power penetration to the grid, beside active power production, Wind Energy Conversion Systems (WECS) are controlled to provide ancillary services such as load balancing and grid power factor correction. Among several converter topology used to design the power converters connecting the Wind Turbine System (WTS) to the grid, the Neutral-Point-Clamped (NPC) topology is attracting the interest of researchers. However, the NPC converter suffers from the Neutral Point (NP) voltage unbalance and, as the case of all the PWM converters, generates the undesirable Common Mode Voltage (CMV). Therefore this paper proposes a predictive current control method for a threelevel NPC grid connected converter capable of simultaneously compensating the problems of : i) Load balancing and power factor correction, ii) NP voltage regulation and iii) CMV reduction. The simulation results show the good performance and the clear capacity of the proposed method to achieve simultaneously the three objectives.