Enhanced Triple Phase Shift Modulation Strategy for ANPC-DAB Converter to Extend Soft Switching Range

In this work, a five-level active-neutral-point clamped (ANPC) full-bridge based dual-active-bridge (DAB) converter is investigated as an extension to conventional DAB converter. The ANPC based DAB (ANPC-DAB) converter not only retains the benefits of the conventional DAB converter, but also can enable application at higher voltages using cost effective low voltage power devices. Given the limitation of soft switching range using the conventional single-phase shift (SPS) modulation, a triple phase shift (TPS) modulation method is developed to extend the soft switching range of ANPC-DAB to a wider range. The key contributions of this work fall into the mathematical modelling, control strategy development and loss distribution evaluation for the ANPC-DAB converter using the proposed TPS modulation. Extensive simulation studies are performed to validate the effectiveness of the proposed TPS modulation for ANPC-DAB converter.