Generalized Predictive Direct Power Control With Constant Switching Frequency for Multilevel Four-Leg Grid Connected Converter

This article proposes a novel generalized predictive direct power control (PDPC) with a constant switching frequency for a multilevel four-leg (4L) grid connected converter (GCC) diode clamped converter (DCC). A new predictive power model for 4L-GCC is developed in which the proposed PDPC can operate with a constant switching frequency without any modulation stage. During each switching period, four appropriate switching vectors are selected and applied using precalculated switching times. Moreover, these appropriate switching vectors are selected only from one sector, and a new proposed approach to calculate the switching times is proposed and generalized for any level of 4L-DCC. The proposed PDPC for the multilevel 4L-GCC can ensure better active and reactive powers control, lower grid current harmonics, better compensation of grid neutral current and reactive power, and accurate balancing of the dc capacitor voltages. The presented results demonstrate the effectiveness of the proposed control strategy.