A Multilevel Hybrid Dual-Active Bridge DC-DC Converter for Energy Storage System in Higher Voltage Applications

In high-voltage applications, conventional two-level dual-active-bridge (DAB) converter have to select high voltage switches to bear the input voltage, leading to high voltage stress and loss. In light of this, a multilevel hybrid dual-active bridge (MH-DAB) DC-DC converter for energy storage system is proposed, which is suitable for high voltage applications. The primary side of the proposed topology is a three-level four-switch half-bridge topology, which does not require any clamping diode or flying capacitor, and the secondary side is a two-level half-bridge. Furthermore, the control algorithm for MH-DAB is developed, where the pulse-width modulation (PWM) plus phase shift (PS) modulation scheme is applied to ensure a reliable power delivery, and meanwhile the two-cycle pulse-width modulation (TC-PWM) is proposed to balance DC-link capacitors voltage and the conduction loss. Finally, the effectiveness of the proposed MH-DAB converter is verified by simulation and experimental results.