Multi-Phase-Shifting Control and Soft-Switching Performance Optimization for a Four-Level ANPC Dual Active Bridge DC-DC Converter

The multilevel dual active bridge (ML-DAB) DC-DC converter has higher operating voltage level than conventional 2L-DAB while retaining advantages like bidirectional power flow, high efficiency. Capacitor voltage balancing (CVB) control and operating performance optimizing (OPO) control are main issues limiting the application of ML-DAB. To decouple the CVB and OPO control, a unified multi-phase-shifting (MPS) control model for ML-DAB is proposed, which significantly simplifies the control and implement of ML-DAB with any levels. The power characteristics of a 4-level active neutral-point clamped DAB (4L-ANPC-DAB) using MPS control model is analyzed. Based on the MPS control, the CVB control and OPO control are both analyzed in this paper, and the soft-switching performance optimization for 4L-ANPC-DAB is introduced. The hardware prototype of 4L-ANPC-DAB is built and experimental and simulation results are presented to verify the proposed MPS control and soft-switching performance optimization for ML-DAB.