A Hybrid Model Predictive Control With Integrated Phase-Disposition and Phase-Shifted PWM for an Inner-Interleaved Hybrid Multilevel Converter

Abstract

This article puts forward a hybrid model predictive control (H-MPC) for an inner-interleaved hybrid multilevel converter (IHMC). The sign patterns of the original and shifted reference vectors in the original and virtual space vector diagrams (VSVDs) are used, respectively, to realize the phase-disposition pulsewidth modulation (PWM) and determine the low-frequency switching states. Then, the three adjacent vectors are selected in the second-layer VSVD and the optimal current tracking is safeguarded by the duty cycle optimization of the three adjacent vectors. Finally, through applying the phase-shifted PWM to the two interleaved legs, a constant and doubled equivalent switching frequency can be achieved, which further paves the way for dc-link and floating capacitor voltages balancing and circulating current mitigation with the use of the straightforward duty cycle adjustments. The proposed H-MPC enables the decoupling of the low- and high-frequency stages in the IHMC and also reduces both output current ripples and computational burden while achieving a constant switching frequency simultaneously. Comprehensive simulation and experimental studies on an all silicon carbide prototype verify the effectiveness of the proposed control strategy.